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Sample records for accurate sonic boom

  1. Sonic boom

    NASA Astrophysics Data System (ADS)

    Maglieri, Domenic J.; Plotkin, Kenneth J.

    1991-08-01

    A status of the knowledge of sonic booms is provided, with emphasis on their generation, propagation and prediction. For completeness, however, material related to the potential for sonic boom alleviation and the response to sonic booms is also included. The material is presented in the following sections: (1) nature of sonic booms; (2) review and status of theory; (3) measurements and predictions; (4) sonic boom minimization; and (5) responses to sonic booms.

  2. Sonic boom research

    NASA Technical Reports Server (NTRS)

    Ting, L.

    1978-01-01

    It is demonstrated that a supersonic airplane configuration weighing over half a million pounds while creating a maximum sonic boom of less than 1 p.s.f. can be designed. New experimental techniques are developed in the wind tunnel and experiments for the sonic boom measurements were carried out. Theoretical analyses were performed for the effects of sonic boom on structures and pollution problems associated with supersonic flights were investigated. Numerical programs were generated for the sonic boom propagations from the near field of an airplane in supersonic flight at high altitude to the ground, taking into account the nonlinear effects and the asymmetric effects due to lift and the spacewise distributions of lift and volume.

  3. Sonic boom acceptability studies

    NASA Astrophysics Data System (ADS)

    Shepherd, Kevin P.; Sullivan, Brenda M.; Leatherwood, Jack D.; McCurdy, David A.

    1992-04-01

    The determination of the magnitude of sonic boom exposure which would be acceptable to the general population requires, as a starting point, a method to assess and compare individual sonic booms. There is no consensus within the scientific and regulatory communities regarding an appropriate sonic boom assessment metric. Loudness, being a fundamental and well-understood attribute of human hearing was chosen as a means of comparing sonic booms of differing shapes and amplitudes. The figure illustrates the basic steps which yield a calculated value of loudness. Based upon the aircraft configuration and its operating conditions, the sonic boom pressure signature which reaches the ground is calculated. This pressure-time history is transformed to the frequency domain and converted into a one-third octave band spectrum. The essence of the loudness method is to account for the frequency response and integration characteristics of the auditory system. The result of the calculation procedure is a numerical description (perceived level, dB) which represents the loudness of the sonic boom waveform.

  4. Sonic boom acceptability studies

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P.; Sullivan, Brenda M.; Leatherwood, Jack D.; Mccurdy, David A.

    1992-01-01

    The determination of the magnitude of sonic boom exposure which would be acceptable to the general population requires, as a starting point, a method to assess and compare individual sonic booms. There is no consensus within the scientific and regulatory communities regarding an appropriate sonic boom assessment metric. Loudness, being a fundamental and well-understood attribute of human hearing was chosen as a means of comparing sonic booms of differing shapes and amplitudes. The figure illustrates the basic steps which yield a calculated value of loudness. Based upon the aircraft configuration and its operating conditions, the sonic boom pressure signature which reaches the ground is calculated. This pressure-time history is transformed to the frequency domain and converted into a one-third octave band spectrum. The essence of the loudness method is to account for the frequency response and integration characteristics of the auditory system. The result of the calculation procedure is a numerical description (perceived level, dB) which represents the loudness of the sonic boom waveform.

  5. Sonic boom configuration minimization

    NASA Technical Reports Server (NTRS)

    Sohn, Robert A.

    1992-01-01

    The topics covered include the following: the sonic boom 'big picture'; current low boom technology; Mach number impact on gross weight; equal loudness equivalent areas; performance and sizing results; potential configuration modifications; equivalent area matching; and impact of nose bluntness on aerodynamic characteristics.

  6. HSCT design for reduced sonic boom

    NASA Technical Reports Server (NTRS)

    Haglund, George T.

    1992-01-01

    The topics covered include the following: low sonic boom design perspective; design approach for reduced sonic boom; target sonic boom waveforms; airplane design for reduced sonic boom loudness; design procedure for low sonic boom; wing design and nacelle lift effects; area distributions and F-functions due to volume; fuselage area distributions; low sonic boom design, configuration 3B; sonic boom characteristics; sizing, performance, and noise characteristics; a summary of phase 3 configurations; impact of sonic boom design constraints; and wing loading considerations.

  7. Research at NASA on Human Response to Sonic Booms

    NASA Technical Reports Server (NTRS)

    Sullivan, Brenda M.

    2008-01-01

    NASA used its sonic boom simulator to study human response to shaped sonic booms and concluded that a loudness metric, such as Perceived Level, predicts human reaction to outdoor booms more accurately than overpressure. To investigate the importance of indoor phenomena (rattle, reverberation) under controlled laboratory conditions, NASA is building an "indoor sonic boom simulator." The intention is to develop a psychoacoustic model that describes human response as a function of boom shape (spectrum), boom intensity, reverberation, and varying rattle characteristics.

  8. Sonic Boom Modeling Technical Challenge

    NASA Technical Reports Server (NTRS)

    Sullivan, Brenda M.

    2007-01-01

    This viewgraph presentation reviews the technical challenges in modeling sonic booms. The goal of this program is to develop knowledge, capabilities and technologies to enable overland supersonic flight. The specific objectives of the modeling are: (1) Develop and validate sonic boom propagation model through realistic atmospheres, including effects of turbulence (2) Develop methods enabling prediction of response of and acoustic transmission into structures impacted by sonic booms (3) Develop and validate psychoacoustic model of human response to sonic booms under both indoor and outdoor listening conditions, using simulators.

  9. Sonic Boom Prediction Exercise: Experimental Comparisons

    NASA Technical Reports Server (NTRS)

    Tu, Eugene; Cheung, Samson; Edwards, Thomas

    1999-01-01

    The success of a future High Speed Civil Transport (HSCT) depends on the ability to accurately assess and, possibly, modify the sonic boom signatures of potential designs. In 1992, the Sonic Boom Steering Committee initiated a prediction exercise to assess the current computational capabilities for the accurate and efficient prediction of sonic boom signatures and loudness levels. A progress report of this effort was given at the Sonic Boom Workshop held at NASA Ames Research Center in 1993 where predictions from CFD and Modified Linear Theory (MLT) methods were given. Comparisons between the methods were made at near-, mid- and far-field locations. However, at that time, experimental data from wind-tunnel tests were not available. The current paper presents a comparison of computational results with the now available experimental data. Further comparisons between the computational methods and analyses of the discrepancies in the results are presented.

  10. Loudness of shaped sonic booms

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P.; Sullivan, Brenda M.

    1990-01-01

    A loudness model is adopted to study the feasibility of designing and operating a supersonic transport to produce minimized sonic booms. The loudness contours in this technique extend to a lower frequency (1 Hz) and thus are appropriate for sonic booms that contain significant low frequency energy. Input to the loudness calculation procedure is the power spectral density of the pressure-time signature. Calculations of loudness, for both indoor and outdoor conditions, demonstrate that shaped sonic booms are potentially more acceptable than N-waves possessing the same peak overpressure.

  11. NASA Ames Sonic Boom Testing

    NASA Technical Reports Server (NTRS)

    Durston, Donald A.; Kmak, Francis J.

    2009-01-01

    Multiple sonic boom wind tunnel models were tested in the NASA Ames Research Center 9-by 7-Foot Supersonic Wind Tunnel to reestablish related test techniques in this facility. The goal of the testing was to acquire higher fidelity sonic boom signatures with instrumentation that is significantly more sensitive than that used during previous wind tunnel entries and to compare old and new data from established models. Another objective was to perform tunnel-to-tunnel comparisons of data from a Gulfstream sonic boom model tested at the NASA Langley Research Center 4-foot by 4-foot Unitary Plan Wind Tunnel.

  12. Seismic detection of sonic booms.

    PubMed

    Cates, Joseph E; Sturtevant, Bradford

    2002-01-01

    The pressure signals from a sonic boom will produce a small, but detectable, ground motion. The extensive seismic network in southern California, consisting of over 200 sites covering over 50000 square kilometers, is used to map primary and secondary sonic boom carpets. Data from the network is used to analyze three supersonic overflights in the western United States. The results are compared to ray-tracing computations using a realistic model of the stratified atmospheric at the time of the measurements. The results show sonic boom ground exposure under the real atmosphere is much larger than previously expected or predicted by ray tracing alone. Finally, seismic observations are used to draw some inferences on the origin of a set of "mystery booms" recorded in 1992-1993 in southern California. PMID:11837967

  13. Real Time Sonic Boom Display

    NASA Technical Reports Server (NTRS)

    Haering, Ed

    2014-01-01

    This presentation will provide general information about sonic boom mitigation technology to the public in order to supply information to potential partners and licensees. The technology is a combination of flight data, atmospheric data and terrain information implemented into a control room real time display for flight planning. This research is currently being performed and as such, any results and conclusions are ongoing.

  14. Georgia Tech sonic boom simulator

    NASA Technical Reports Server (NTRS)

    Ahuja, Krish K.

    1992-01-01

    To examine the building and human response to sonic boom in the range 3 Hz to 30 Hz, Georgia Institute of Technology is building a special acoustic driver system to simulate sonic boom. To support the NASA LaRC program on building and human response, this simulator's capability has been extended to an upper frequency of 4 KHz. A residential test house was made available by Georgia Tech for these tests. At the time of preparation of this document, most of the acoustic drivers and the associated electronics have been built and assembled. The system has, however, not been fully tested. The following pages provide an overview of the progress to date. The acoustic driver systems, and the principle of their operation together with the test house are described. Future plans are also summarized.

  15. On the aging of sonic booms

    NASA Technical Reports Server (NTRS)

    Plotkin, Kenneth J.

    1994-01-01

    This paper presents view-graphs and notes on sonic boom aging. Topic covered include sonic boom propagation, George's minimized F-function, final minimum shock boom, amplitude and age parameters, off-track aging, scaling flight test experiments, the potential for thin shocks, and results of a Boomfile flight test that showed significant waveform distortion.

  16. Unstructured grids for sonic-boom analysis

    NASA Technical Reports Server (NTRS)

    Fouladi, Kamran

    1993-01-01

    A fast and efficient unstructured grid scheme is evaluated for sonic-boom applications. The scheme is used to predict the near-field pressure signatures of a body of revolution at several body lengths below the configuration, and those results are compared with experimental data. The introduction of the 'sonic-boom grid topology' to this scheme make it well suited for sonic-boom applications, thus providing an alternative to conventional multiblock structured grid schemes.

  17. Realism Assessment of Sonic Boom Simulators

    NASA Technical Reports Server (NTRS)

    Sullivan, Brenda M.; Davies, Patrica; Hodgdon, Kthleen K.; Salamone, Joseph A., III; Pilon, Anthony

    2008-01-01

    Developments in small supersonic aircraft design are predicted to result in low-intensity sonic booms. Booms generated by current aircraft are similar to those that led to the ban on commercial supersonic fli ght over the US, so are unsuitable for parametric studies of psychoac oustic response to low-intensity booms. Therefore, simulators have be en used to study the impact of predicted low-intensity sonic booms. H owever, simulators have been criticized because, when simulating conv entional-level booms, the sounds were observed to be unrealistic by p eople experienced in listening to sonic booms. Thus, two studies were conducted to measure the perceived realism of three sonic boom simul ators. Experienced listeners rated the realism of conventional sonic boom signatures when played in these simulators. The effects on percei ved realism of factors such as duration of post-boom noise, exclusion of very low frequency components, inclusion of ground reflections, a nd type of simulator were examined. Duration of post-boom noise was f ound to have a strong effect on perceived realism, while type of simu lator had a weak effect. It was determined that post-boom noise had t o be at least 1.5 seconds long for the sound to be rated very realist ic. Loudness level did not affect realism for the range of sounds pla yed in the tests (80-93 dB ASEL).

  18. Status of sonic boom methodology and understanding

    NASA Technical Reports Server (NTRS)

    Darden, Christine M.; Powell, Clemans A.; Hayes, Wallace D.; George, Albert R.; Pierce, Allan D.

    1989-01-01

    In January 1988, approximately 60 representatives of industry, academia, government, and the military gathered at NASA-Langley for a 2 day workshop on the state-of-the-art of sonic boom physics, methodology, and understanding. The purpose of the workshop was to assess the sonic boom area, to determine areas where additional sonic boom research is needed, and to establish some strategies and priorities in this sonic boom research. Attendees included many internationally recognized sonic boom experts who had been very active in the Supersonic Transport (SST) and Supersonic Cruise Aircraft Research Programs of the 60's and 70's. Summaries of the assessed state-of-the-art and the research needs in theory, minimization, atmospheric effects during propagation, and human response are given.

  19. Supersonic aircraft optimization for minimizing drag and sonic boom

    NASA Astrophysics Data System (ADS)

    Chan, Martin Kia-Yin

    A design tool incorporating classical sonic boom theory, computational fluid dynamics and a multi-objective genetic algorithm was developed for low-boom supersonic aircraft optimization. Both sonic boom and drag were optimized simultaneously and a Pareto optimal set of designs ranging from minimum boom to minimum drag was obtained for each optimization. Since sonic boom was optimized directly, the method had broader applicability than the traditional inverse method. A high-order three-dimensional panel method was used for sonic boom prediction. The traditional linear source model was fast but did not account for wing-body aerodynamic interaction. Euler solutions were expensive for computing sonic booms because a large number of grid points were needed to accurately predict the pressure signature away from the aircraft. For the Mach number and configurations of interest, the panel code showed good agreement with Euler but at a fraction of the cost. A loudness metric was shown to have advantages over initial overpressure and peak overpressure for measuring shaped sonic booms. However, optimization results obtained using calculated loudness raised concerns about the robustness of the solution to atmospheric disturbance. Peak overpressure minimization also produced reasonable sonic boom signatures and appeared more robust to atmospheric uncertainties, but the resulting loudness was not as good. Better convergence was also observed with peak overpressure. Two supersonic business jets were optimized. One was a conventional configuration; the other was a natural laminar flow configuration. Optimization results obtained using loudness and peak overpressure were compared. A non-axisymmetric fuselage was optimized and found to reduce the inviscid drag by 9 to 30 percent at the same sonic boom loudness.

  20. Sonic boom interaction with turbulence

    NASA Technical Reports Server (NTRS)

    Rusak, Zvi; Giddings, Thomas E.

    1994-01-01

    A recently developed transonic small-disturbance model is used to analyze the interactions of random disturbances with a weak shock. The model equation has an extended form of the classic small-disturbance equation for unsteady transonic aerodynamics. It shows that diffraction effects, nonlinear steepening effects, focusing and caustic effects and random induced vorticity fluctuations interact simultaneously to determine the development of the shock wave in space and time and the pressure field behind it. A finite-difference algorithm to solve the mixed-type elliptic hyperbolic flows around the shock wave is presented. Numerical calculations of shock wave interactions with various deterministic vorticity and temperature disturbances result in complicate shock wave structures and describe peaked as well as rounded pressure signatures behind the shock front, as were recorded in experiments of sonic booms running through atmospheric turbulence.

  1. Real-Time, Interactive Sonic Boom Display

    NASA Technical Reports Server (NTRS)

    Haering, Jr., Edward A. (Inventor); Plotkin, Kenneth J. (Inventor)

    2012-01-01

    The present invention is an improved real-time, interactive sonic boom display for aircraft. By using physical properties obtained via various sensors and databases, the invention determines, in real-time, sonic boom impacts locations and intensities for aircraft traveling at supersonic speeds. The information is provided to a pilot via a display that lists a selectable set of maneuvers available to the pilot to mitigate sonic boom issues. Upon selection of a maneuver, the information as to the result of the maneuver is displayed and the pilot may proceed with making the maneuver, or provide new data to the system in order to calculate a different maneuver.

  2. HSCT designs for reduced sonic boom

    NASA Technical Reports Server (NTRS)

    Haglund, George T.

    1991-01-01

    The versatility of High Speed Civil Transports (HSCT) will be operationally limited by regulations that prohibit overland supersonic flight. This limitation gives impetus to the study of aerodynamic designs for reduced sonic boom. An HSCT design with an 'acceptable' sonic boom can allow routine overland supersonic cruise that would provide increased productivity and economic viability. During this four-year NASA-sponsored study, several configurations were designed for reduced sonic boom. An iterative technique was used in which the standard linear supersonic and Whitham sonic boom methods are extended. For the most severe sonic boom constraint of 72 dBA sonic boom loudness and 0.75 lb/sq ft shock strength at the ground, an economic benefit for operating at Mach 1.7 overland was not realized because of a decrease in the ratio of payload to takeoff gross weight. Additional design work is required to develop the best compromise between the low-boom requirements and optimum cruise performance.

  3. Multidisciplinary design optimization for sonic boom mitigation

    NASA Astrophysics Data System (ADS)

    Ozcer, Isik A.

    Automated, parallelized, time-efficient surface definition and grid generation and flow simulation methods are developed for sharp and accurate sonic boom signal computation in three dimensions in the near and mid-field of an aircraft using Euler/Full-Potential unstructured/structured computational fluid dynamics. The full-potential mid-field sonic boom prediction code is an accurate and efficient solver featuring automated grid generation, grid adaptation and shock fitting, and parallel processing. This program quickly marches the solution using a single nonlinear equation for large distances that cannot be covered with Euler solvers due to large memory and long computational time requirements. The solver takes into account variations in temperature and pressure with altitude. The far-field signal prediction is handled using the classical linear Thomas Waveform Parameter Method where the switching altitude from the nonlinear to linear prediction is determined by convergence of the ground signal pressure impulse value. This altitude is determined as r/L ≈ 10 from the source for a simple lifting wing, and r/L ≈ 40 for a real complex aircraft. Unstructured grid adaptation and shock fitting methodology developed for the near-field analysis employs an Hessian based anisotropic grid adaptation based on error equidistribution. A special field scalar is formulated to be used in the computation of the Hessian based error metric which enhances significantly the adaptation scheme for shocks. The entire cross-flow of a complex aircraft is resolved with high fidelity using only 500,000 grid nodes after only about 10 solution/adaptation cycles. Shock fitting is accomplished using Roe's Flux-Difference Splitting scheme which is an approximate Riemann type solver and by proper alignment of the cell faces with respect to shock surfaces. Simple to complex real aircraft geometries are handled with no user-interference required making the simulation methods suitable tools for

  4. Low Sonic Boom Design Activities at Boeing

    NASA Technical Reports Server (NTRS)

    Haglund, George T.

    1999-01-01

    Low sonic boom studies have continued during the last year with the goal of exploring the ability of practical airplane designs to achieve significantly reduced sonic boom-loudness with reasonable performance penalties. At the 1993 Sonic Boom Workshop, improvements to the low-boom design methods were described and early results of two low-boom configurations -935 and -936) were presented. Now that the low boom design methods are reasonably mature, recent design activities have broadened somewhat to explore refinements to the -935 and -936 designs. In this paper the results are reported of a detailed systems study and performance sizing of the -935 (Hybrid sonic boom waveform) and the -936 (Flat-top waveform). This analysis included a second design cycle for reduced cruise drag and balance considerations. Another design study was of a small-wing version of the -935. Finally, some preliminary results of the recent LARC UPWT test of the -935 configuration are given, along with a proposed alternative method for extrapolating wind tunnel pressure signatures to the ground. The various configurations studied is also summarized. The topics covered by this paper are as follows: Systems study results of the Baseline -939 and low boom configurations -935 and -936, Small wing derivative of the -935, Wind tunnel test results of the -935, Test-derived F-function and propagation to the ground, and Future considerations (boom-softened baseline, overwater issues, and operations).

  5. NASA Engineer Larry Cliatt: Softening Sonic Booms

    NASA Video Gallery

    A sudden sonic boom can startle persons unfamiliar with the phenomenon. As a result, supersonic flight over the United States is currently prohibited, except in several restricted testing areas. La...

  6. Sonic Boom: Six Decades of Research

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Bobbitt, Percy J.; Plotkin, Kenneth J.; Shepherd, Kevin P.; Coen, Peter G.; Richwine, David M.

    2014-01-01

    Sonic booms generated by aircraft traveling at supersonic speeds have been the subject of extensive aeronautics research for over 60 years. Hundreds of papers have been published that document the experimental and analytical research conducted during this time period. The purpose of this publication is to assess and summarize this work and establish the state-of-the-art for researchers just entering the field, or for those interested in a particular aspect of the subject. This publication consists of ten chapters that cover the experimental and analytical aspects of sonic boom generation, propagation and prediction with summary remarks provided at the end of each chapter. Aircraft maneuvers, sonic boom minimization, simulation techniques and devices as well as human, structural, and other responses to sonic booms are also discussed. The geometry and boom characteristics of various low-boom concepts, both large civil transports and smaller business-jet concepts, are included. The final chapter presents an assessment of civilian supersonic overland flight and highlights the need for continued research and a low-boom demonstrator vehicle. Summary remarks are provided at the end of each chapter. The studies referenced in this publication have been drawn from over 500 references.

  7. Experimental and Computational Sonic Boom Assessment of Lockheed-Martin N+2 Low Boom Models

    NASA Technical Reports Server (NTRS)

    Cliff, Susan E.; Durston, Donald A.; Elmiligui, Alaa A.; Walker, Eric L.; Carter, Melissa B.

    2015-01-01

    Flight at speeds greater than the speed of sound is not permitted over land, primarily because of the noise and structural damage caused by sonic boom pressure waves of supersonic aircraft. Mitigation of sonic boom is a key focus area of the High Speed Project under NASA's Fundamental Aeronautics Program. The project is focusing on technologies to enable future civilian aircraft to fly efficiently with reduced sonic boom, engine and aircraft noise, and emissions. A major objective of the project is to improve both computational and experimental capabilities for design of low-boom, high-efficiency aircraft. NASA and industry partners are developing improved wind tunnel testing techniques and new pressure instrumentation to measure the weak sonic boom pressure signatures of modern vehicle concepts. In parallel, computational methods are being developed to provide rapid design and analysis of supersonic aircraft with improved meshing techniques that provide efficient, robust, and accurate on- and off-body pressures at several body lengths from vehicles with very low sonic boom overpressures. The maturity of these critical parallel efforts is necessary before low-boom flight can be demonstrated and commercial supersonic flight can be realized.

  8. Disturbance of sleep by sonic booms.

    PubMed

    Griefahn, B; Jansen, G

    1975-05-01

    After a pilot study (2 subjects, 19 nights) we tested two different subjects during 57 nights, administering sonic booms (1 mb, 300 ms; sound level of sonic boom in the bedroom 80-85 dB (A) and recording EEG and peripheral blood volume. After 7 nights without noise, 30 nights with either 2 or 4 sonic booms (alternately) were applied. After 10 more nights without noise, four nights with 8 and 16 bangs followed alternately. The last 6 nights were used as a comparison phase. Results showed that distrubance was obvious during all periods of noise. No adaptation could be observed during any of the experiments. On the contrary, during the night with 4 bangs there was a tendency for compensation, e.g., in the last two thirds of nights with 4 bangs, the total time of deep sleep was comparable with the nights without any noise. PMID:1145178

  9. Scattering of sonic booms by anisotropic turbulence in the atmosphere

    PubMed

    Kelly; Raspet; Bass

    2000-06-01

    An earlier paper [J. Acoust. Soc. Am. 98, 3412-3417 (1995)] reported on the comparison of rise times and overpressures of sonic booms calculated with a scattering center model of turbulence to measurements of sonic boom propagation through a well-characterized turbulent layer under moderately turbulent conditions. This detailed simulation used spherically symmetric scatterers to calculate the percentage of occurrence histograms of received overpressures and rise times. In this paper the calculation is extended to include distorted ellipsoidal turbules as scatterers and more accurately incorporates the meteorological data into a determination of the number of scatterers per unit volume. The scattering center calculation overpredicts the shifts in rise times for weak turbulence, and still underpredicts the shift under more turbulent conditions. This indicates that a single-scatter center-based model cannot completely describe sonic boom propagation through atmospheric turbulence. PMID:10875351

  10. Status and capabilities of sonic boom simulators

    NASA Technical Reports Server (NTRS)

    Shepherd, K. P.; Powell, C. A.

    1986-01-01

    The current status and capabilities of sonic boom simulators which might be used in future studies of the effects of sonic boom on people, animals, or structures is summarized. The list of candidate simulators is based on a literature search which was confined to the United States and Canada. Some of the simulators are fully operational, others could be made operational with a modest investment, and still others would require a major investment. For the sake of the completeness, some simulators which were the subject of a previous review, but which no longer exist, are also included herein.

  11. NASA Studies Sonic Booms' Effect on Big Structures

    NASA Video Gallery

    NASA recently conducted flight experiments at Edwards Air Force Base in Southern California to examine the effect of low-amplitude sonic booms on large office buildings. As part of the Sonic Booms ...

  12. A model experiment to study sonic boom propagation through turbulence. Part III: validation of sonic boom propagation models.

    PubMed

    Lipkens, Bart

    2002-01-01

    In previous papers, we have shown that model experiments are successful in simulating the propagation of sonic booms through the atmospheric turbulent boundary layer. The results from the model experiment, pressure wave forms of spark-produced N waves and turbulence characteristics of the plane jet, are used to test various sonic boom models for propagation through turbulence. Both wave form distortion models and rise time prediction models are tested. Pierce's model [A. D. Pierce, "Statistical theory of atmospheric turbulence effects on sonic boom rise times," J. Acoust. Soc. Am. 49, 906-924 (1971)] based on the wave front folding mechanism at a caustic yields an accurate prediction for the rise time of the mean wave form after propagation through the turbulence. PMID:11837956

  13. A Compilation of Space Shuttle Sonic Boom Measurements - Supplemental STS Sonic Boom Files

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Henderson, Herbert R.; Massey, Steven J.; Stansbery, Eugene G.

    2011-01-01

    Supplemental STS Sonic Boom Files for NASA/CR-2011-217080. Data files included on CDROM formatted to ISO 9660 standards. Sonic boom measurements have been obtained on 26 flights of the Space Shuttle system beginning with the launch of STS-1 on April 12, 1981, to the reentry-descent of STS-41 into EAFB on Oct. 10, 1990. A total of 23 boom measurements were acquired within the focus region off the Florida coast during 3 STS launch-ascents and 113 boom measurements were acquired during 23 STS reentry-descent to landing into Florida and California. Sonic boom measurements were made under, and lateral to, the vehicle ground track and cover the Mach-altitude range of about 1.3 to 23 and 54,000 feet to 243,000 feet, respectively. Vehicle operational data, flight profiles and weather data were also gathered during the flights. This STS boom database is contained in 26 documents, some are formal and referenceable but most internal documents. Another 38 documents, also non-referenceable, contain predicted sonic boom footprints for reentry-descent flights on which no measurements were made. The purpose of this report is to provide an overview of the STS sonic boom database and summarize the main findings.

  14. 14 CFR 91.817 - Civil aircraft sonic boom.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Civil aircraft sonic boom. 91.817 Section....817 Civil aircraft sonic boom. (a) No person may operate a civil aircraft in the United States at a... sonic boom to reach the surface within the United States; and (2) The operator complies with the...

  15. 14 CFR 91.817 - Civil aircraft sonic boom.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Civil aircraft sonic boom. 91.817 Section....817 Civil aircraft sonic boom. (a) No person may operate a civil aircraft in the United States at a... sonic boom to reach the surface within the United States; and (2) The operator complies with the...

  16. 14 CFR 91.817 - Civil aircraft sonic boom.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Civil aircraft sonic boom. 91.817 Section....817 Civil aircraft sonic boom. (a) No person may operate a civil aircraft in the United States at a... sonic boom to reach the surface within the United States; and (2) The operator complies with the...

  17. 14 CFR 91.817 - Civil aircraft sonic boom.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Civil aircraft sonic boom. 91.817 Section....817 Civil aircraft sonic boom. (a) No person may operate a civil aircraft in the United States at a... sonic boom to reach the surface within the United States; and (2) The operator complies with the...

  18. Atmospheric effects on the risetime and waveshape of sonic booms

    NASA Technical Reports Server (NTRS)

    Raspet, Richard; Bass, Henry E.; Boulanger, Patrice

    1994-01-01

    Accurate prediction of human response to sonic booms from proposed HSCT aircraft depends on a knowledge of the waveshape and risetime of the boom at the ground. In previous work, we have developed a numerical technique to predict the combined effects of molecular absorption and finite wave distortion on the sonic boom as it propagates from the aircraft to the top of the turbulent boundary layer. We have more recently developed a scattering center based model to calculate the effects of turbulence on the sonic boom waveform as it propagates through this boundary layer. Calculations have been performed using single scales of turbulence and compared to measurements at Edwards AFB in the late 1960's. A model of the atmosphere involving two scales each for convective and mechanical turbulence has been developed and fit to meteorological data collected during JAPE 2. Scattering calculations employing this model underpredict the number of unperturbed waveforms. In order to develop a more realistic model of the atmosphere, the JAPE 2 meteorological data has been fit to a von Karman spectrum. Results of scattering using this multi-scale model will be presented. The combination of finite wave effects with turbulent scattering predictions includes the principal effects of the atmosphere on the sonic boom from the HSCT.

  19. A Quick Method for Evaluating the Merits of a Proposed Low Sonic Boom Concept

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    2003-01-01

    The characteristics of a proposed low-boom aircraft concept cannot be adequately assessed unless it is given an extensive, time-consuming, mission-performance, and sonic-boom analyses. So, it would be useful to have a method for performing a quick first-order sonic-boom and mission-range analysis. The evaluation method outlined in this report has the attributes of being both fast and reasonably accurate. It can also be used as a design tool to estimate the sonic-boom ground overpressures, mission range, and beginning-cruise weight of a new low-boom concept during the first stages of preliminary design.

  20. Subjective loudness response to simulated sonic booms

    NASA Technical Reports Server (NTRS)

    Leatherwood, Jack D.; Sullivan, Brenda M.

    1992-01-01

    A series of laboratory studies were conducted at LaRC to: (1) quantify the effects of sonic boom signature shaping on subjective loudness; (2) evaluate candidate loudness metrics; (3) quantify the effects of signature asymmetry on loudness; and (4) document sonic boom acceptability within the laboratory. A total of 212 test subjects evaluated a wide range of signatures using the NASA Langley Research Center's sonic boom simulator. Results indicated that signature shaping via front-shock minimization was particularly effective in reducing subjective loudness without requiring reductions in peak overpressure. Metric evaluations showed that A-weighted sound exposure level, Perceived Level (Stevens Mark 7), and Zwicker's Loudness level were effective descriptors of the loudness of symmetrical shaped signatures. The asymmetrical signatures were generally rated as being quieter than symmetrical signatures of equal calculated metric level. The magnitude of the loudness reductions were observed to increase as the degree of asymmetry increased and to be greatest when the rear half of the signature was loudest. This effect was not accounted for by the loudness metrics. Sonic boom acceptability criteria were determined within the laboratory. These agreed well with results previously obtained in more realistic situations.

  1. Variability of measured sonic boom signatures

    NASA Technical Reports Server (NTRS)

    Elmer, K. R.; Joshi, M. C.

    1994-01-01

    The topics discussed include the following: atmospheric turbulence; BOOMFILE Database description; BOOMFILE flight conditions; XB-70 Database descriptions; analysis progression; extended database; prediction method; overpressure variability dependence on flight conditions; loudness variability on flight conditions; sonic boom variability in repeat flights; and statistical distributions.

  2. Human Response to Simulated Low-Intensity Sonic Booms

    NASA Technical Reports Server (NTRS)

    Sullivan, Brenda M.

    2004-01-01

    NASA's High Speed Research (HSR ) program in the 1990s was intended to develop a technology base for a future High-Speed Civil Transport (HSCT). As part of this program, the NASA Langley Research Center sonic boom simulator (SBS) was built and used for a series of tests on subjective response to sonic booms. At the end of the HSR program, an HSCT was deemed impractical, but since then interest in supersonic flight has reawakened, this time focusing on a smaller aircraft suitable for a business jet. To respond to this interest, the Langley sonic boom simulator has been refurbished. The upgraded computer-controlled playback system is based on an SGI O2 computer, in place of the previous DEC MicroVAX. As the frequency response of the booth is not flat, an equalization filter is required. Because of the changes made during the renovation (new loudspeakers), the previous equalization filter no longer performed as well as before, so a new equalization filter has been designed. Booms to be presented in the booth are preprocessed using the filter. When the preprocessed signals are presented into the booth and measured with a microphone, the results are very similar to the intended shapes. Signals with short rise times and sharp "corners" are observed to have a small amount of "ringing" in the response. During the HSR program a considerable number of subjective tests were completed in the SBS. A summary of that research is given in Leatherwood et al. (Individual reports are available at http://techreports.larc.nasa.gov/ltrs/ltrs.html.) Topics of study included shaped sonic booms, asymmetrical booms, realistic (recorded) boom waveforms, indoor and outdoor booms shapes, among other factors. One conclusion of that research was that a loudness metric, like the Stevens Perceived Level (PL), predicted human reaction much more accurately than overpressure or unweighted sound pressure level. Structural vibration and rattle were not included in these studies.

  3. Measured N-wave sonic boom events and sensitivity in sonic boom metrics

    NASA Astrophysics Data System (ADS)

    Palmer, Joshua; Sparrow, Victor W.

    2015-10-01

    Various sonic boom noise metrics have been calculated for a number of sonic boom, N-wave signatures. The newly computed metrics dataset utilized high-quality recordings from the Superboom Caustic Analysis and Measurement Program (SCAMP) experiment conducted by NASA. With this signature dataset comprised of microphone measurements by long linear arrays, one can assess the waveform variability due to atmospheric turbulence influences across the arrays. Preferred boom events from these NASA datasets were then chosen after review of the flight conditions, flight objectives and actual waveforms generated in order to study only the non-focused, N-wave sonic boom signatures. The sonic boom noise metrics calculated for the preferred boom events include Stevens Mark VII Perceived Level (PLdB), un-weighted Sound Exposure Level (SELz) as well as Sound Exposure Level with A, B, C, D, and E weightings applied to the waveforms. The results show, for example, that the A-weighted sound exposure levels and Steven's Mark VII Perceived Levels had standard deviations in the range of 1.4 dB to 6.1 dB for the SCAMP measurements. Such sensitivity results should be helpful in assessing the applicability of sonic boom metrics for use in future en-route certification standards for civilian supersonic aircraft.

  4. Sonic-boom research: Selected bibliography with annotation

    NASA Technical Reports Server (NTRS)

    Hubbard, H. H.; Maglieri, D. J.; Stephens, D. G.

    1986-01-01

    Citations of selected documents are included which represent the state of the art of technology in each of the following subject areas: prediction, measurement, and minimization of steady-flight sonic booms; prediction and measurement of accelerating-flight sonic booms; sonic-boom propagation; the effects of sonic booms on people, communities, structures, animals, birds, and terrain; and sonic-boom simulator technology. Documents are listed in chronological order in each section of the paper, with key documents and associated annotation listed first. The sources are given along with acquisition numbers, when available, to expedite the acquisition of copies of the documents.

  5. High speed civil transport: Sonic boom softening and aerodynamic optimization

    NASA Astrophysics Data System (ADS)

    Cheung, Samson

    1994-07-01

    An improvement in sonic boom extrapolation techniques has been the desire of aerospace designers for years. This is because the linear acoustic theory developed in the 60's is incapable of predicting the nonlinear phenomenon of shock wave propagation. On the other hand, CFD techniques are too computationally expensive to employ on sonic boom problems. Therefore, this research focused on the development of a fast and accurate sonic boom extrapolation method that solves the Euler equations for axisymmetric flow. This new technique has brought the sonic boom extrapolation techniques up to the standards of the 90's. Parallel computing is a fast growing subject in the field of computer science because of its promising speed. A new optimizer (IIOWA) for the parallel computing environment has been developed and tested for aerodynamic drag minimization. This is a promising method for CFD optimization making use of the computational resources of workstations, which unlike supercomputers can spend most of their time idle. Finally, the OAW concept is attractive because of its overall theoretical performance. In order to fully understand the concept, a wind-tunnel model was built and is currently being tested at NASA Ames Research Center. The CFD calculations performed under this cooperative agreement helped to identify the problem of the flow separation, and also aided the design by optimizing the wing deflection for roll trim.

  6. High speed civil transport: Sonic boom softening and aerodynamic optimization

    NASA Technical Reports Server (NTRS)

    Cheung, Samson

    1994-01-01

    An improvement in sonic boom extrapolation techniques has been the desire of aerospace designers for years. This is because the linear acoustic theory developed in the 60's is incapable of predicting the nonlinear phenomenon of shock wave propagation. On the other hand, CFD techniques are too computationally expensive to employ on sonic boom problems. Therefore, this research focused on the development of a fast and accurate sonic boom extrapolation method that solves the Euler equations for axisymmetric flow. This new technique has brought the sonic boom extrapolation techniques up to the standards of the 90's. Parallel computing is a fast growing subject in the field of computer science because of its promising speed. A new optimizer (IIOWA) for the parallel computing environment has been developed and tested for aerodynamic drag minimization. This is a promising method for CFD optimization making use of the computational resources of workstations, which unlike supercomputers can spend most of their time idle. Finally, the OAW concept is attractive because of its overall theoretical performance. In order to fully understand the concept, a wind-tunnel model was built and is currently being tested at NASA Ames Research Center. The CFD calculations performed under this cooperative agreement helped to identify the problem of the flow separation, and also aided the design by optimizing the wing deflection for roll trim.

  7. Concorde sonic booms as an atmospheric probe.

    PubMed

    Balachandran, N K; Donn, W L; Rind, D H

    1977-07-01

    Infrasound generated by the sonic boom from the inbound Concorde supersonic transport is recorded at Palisades, New York (Lamont-Doherty Geological Observatory), as a series of impulses from distances varying from 165 to about 1000 kilometers. Refraction effects determined by temperature and wind conditions return the signal to the surface from both stratospheric (40 to 50 kilometers) and thermospheric (100 to 130 kilometers) levels. The frequency of the recorded signal is a function of the level of reflection; the frequency decreases from impulse stretching as the atmosphere becomes more rarified relative to the sound pressure. The horizontal trace velocity of the signal across the array of instruments is equal to the acoustic velocity at the reflection level. The sonic boom can thus be used to provide temperature-wind parameters at reflection levels estimated from the signal frequency. Daily observed signal variations have indicated significant variations in these parameters. PMID:17828888

  8. High-Quality Seismic Observations of Sonic Booms

    NASA Astrophysics Data System (ADS)

    Wurman, G.; Haering, E. A.; Price, M.

    2011-12-01

    The SonicBREWS project (Sonic Boom Resistant Earthquake Warning Systems) is a collaborative effort between Seismic Warning Systems, Inc. and NASA Dryden Flight Research Center. This project aims to evaluate the effects of sonic booms on Earthquake Warning Systems in order to prevent such systems from experiencing false alarms due to sonic booms. The airspace above the Antelope Valley, California includes the High Altitude Supersonic Corridor and the Black Mountain Supersonic Corridor. These corridors are among the few places in the US where supersonic flight is permitted, and sonic booms are commonplace in the Antelope Valley. One result of this project is a rich dataset of high-quality accelerometer records of sonic booms which can shed light on the interaction between these atmospheric phenomena and the solid earth. Nearly 100 sonic booms were recorded with low-noise triaxial MEMS accelerometers recording 1000 samples per second. The sonic booms had peak overpressures ranging up to approximately 10 psf and were recorded in three flight series in 2010 and 2011. Each boom was recorded with up to four accelerometers in various array configurations up to 100 meter baseline lengths, both in the built environment and the free field. All sonic booms were also recorded by nearby microphones. We present the results of the project in terms of the potential for sonic-boom-induced false alarms in Earthquake Warning Systems, and highlight some of the interesting features of the dataset.

  9. High-Quality Seismic Observations of Sonic Booms

    NASA Technical Reports Server (NTRS)

    Wurman, Gilead; Haering, Edward A., Jr.; Price, Michael J.

    2011-01-01

    The SonicBREWS project (Sonic Boom Resistant Earthquake Warning Systems) is a collaborative effort between Seismic Warning Systems, Inc. and NASA Dryden Flight Research Center. This project aims to evaluate the effects of sonic booms on Earthquake Warning Systems in order to prevent such systems from experiencing false alarms due to sonic booms. The airspace above the Antelope Valley, California includes the High Altitude Supersonic Corridor and the Black Mountain Supersonic Corridor. These corridors are among the few places in the US where supersonic flight is permitted, and sonic booms are commonplace in the Antelope Valley. One result of this project is a rich dataset of high-quality accelerometer records of sonic booms which can shed light on the interaction between these atmospheric phenomena and the solid earth. Nearly 100 sonic booms were recorded with low-noise triaxial MEMS accelerometers recording 1000 samples per second. The sonic booms had peak overpressures ranging up to approximately 10 psf and were recorded in three flight series in 2010 and 2011. Each boom was recorded with up to four accelerometers in various array configurations up to 100 meter baseline lengths, both in the built environment and the free field. All sonic booms were also recorded by nearby microphones. We present the results of the project in terms of the potential for sonic-boom-induced false alarms in Earthquake Warning Systems, and highlight some of the interesting features of the dataset.

  10. Experimental studies of loudness and annoyance response to sonic booms

    NASA Technical Reports Server (NTRS)

    Sullivan, Brenda M.; Leatherwood, Jack D.

    1994-01-01

    The purpose of this paper is to summarize the most recent sonic boom laboratory studies performed at NASA-LaRC using the Sonic Boom Simulator. The first used synthesized idealized outdoor boom shapes which were filtered to represent booms heard inside a house. The test explored the efficacy of various metrics in assessing both loudness and annoyance responses to these booms. The second test investigated the effects of adding single reflections to idealized boom signatures, and the third compared booms recorded from real aircraft with idealized boom signatures to determine if subjects rated the real booms differently. In these studies, as in previous studies performed at NASA-LaRC, there was a continuing effort to evaluate metrics for predicting the subjective effects of sonic booms.

  11. Flight test measurements and analysis of sonic boom phenomena near the shock wave extremity

    NASA Technical Reports Server (NTRS)

    Haglund, G. T.; Kane, E. J.

    1973-01-01

    The sonic boom flight test program conducted at Jackass Flats, Nevada, during the summer and fall of 1970 consisted of 121 sonic-boom-generating flights over the 1500 ft instrumented BREN tower. This test program was designed to provide information on several aspects of sonic boom, including caustics produced by longitudinal accelerations, caustics produced by steady flight near the threshold Mach number, sonic boom characteristics near lateral cutoff, and the vertical extent of shock waves attached to near-sonic airplanes. The measured test data, except for the near-sonic flight data, were analyzed in detail to determine sonic boom characteristics for these flight conditions and to determine the accuracy and the range of validity of linear sonic boom theory. The caustic phenomena observed during the threshold Mach number flights and during the transonic acceleration flights are documented and analyzed in detail. The theory of geometric acoustics is shown to be capable of predicting shock wave-ground intersections, and current methods for calculating sonic boom pressure signature away from caustics are shown to be reasonably accurate.

  12. NASA Researches the 'FaINT' Side of Sonic Booms

    NASA Video Gallery

    As the latest in a continuing progression of NASA supersonics research projects aimed at reducing or mitigating the effect of sonic booms, the Farfield Investigation of No Boom Threshold, or FaINT,...

  13. Sonic Boom Computations for a Mach 1.6 Cruise Low Boom Configuration and Comparisons with Wind Tunnel Data

    NASA Technical Reports Server (NTRS)

    Elmiligui, Alaa A.; Cliff, Susan E.; Wilcox, Floyd; Nemec, Marian; Bangert, Linda; Aftosmis, Michael J.; Parlette, Edward

    2011-01-01

    Accurate analysis of sonic boom pressure signatures using computational fluid dynamics techniques remains quite challenging. Although CFD shows accurate predictions of flow around complex configurations, generating grids that can resolve the sonic boom signature far away from the body is a challenge. The test case chosen for this study corresponds to an experimental wind-tunnel test that was conducted to measure the sonic boom pressure signature of a low boom configuration designed by Gulfstream Aerospace Corporation. Two widely used NASA codes, USM3D and AERO, are examined for their ability to accurately capture sonic boom signature. Numerical simulations are conducted for a free-stream Mach number of 1.6, angle of attack of 0.3 and Reynolds number of 3.85x10(exp 6) based on model reference length. Flow around the low boom configuration in free air and inside the Langley Unitary plan wind tunnel are computed. Results from the numerical simulations are compared with wind tunnel data. The effects of viscous and turbulence modeling along with tunnel walls on the computed sonic boom signature are presented and discussed.

  14. A total variation diminishing finite difference algorithm for sonic boom propagation models

    NASA Technical Reports Server (NTRS)

    Sparrow, Victor W.

    1993-01-01

    It is difficult to accurately model the rise phases of sonic boom waveforms with traditional finite difference algorithms because of finite difference phase dispersion. This paper introduces the concept of a total variation diminishing (TVD) finite difference method as a tool for accurately modeling the rise phases of sonic booms. A standard second order finite difference algorithm and its TVD modified counterpart are both applied to the one-way propagation of a square pulse. The TVD method clearly outperforms the non-TVD method, showing great potential as a new computational tool in the analysis of sonic boom propagation.

  15. High-Speed Research: Sonic Boom, volume 1

    NASA Technical Reports Server (NTRS)

    Darden, Christine M. (Compiler)

    1992-01-01

    A High-Speed Sonic Boom Workshop was held at LaRC of Feb. 25-27, 1992. The purpose was to make presentations on current research activities and accomplishments and to assess progress in the area of sonic boom since the program was initiated in FY-90. Twenty-nine papers were presented during the 2-1/2 day workshop. Attendees included representatives from academia, industry, and government who are actively involved in sonic-boom research. Volume 1 contains papers related to atmospheric effects on the sonic-boom signature during propagation and on acceptability studies.

  16. High-Speed Research: Sonic Boom, volume 2

    NASA Technical Reports Server (NTRS)

    Darden, Christine M. (Compiler)

    1992-01-01

    A High-Speed Sonic Boom Workshop was held at NASA Langley Research Center on February 25-27, 1992. The purpose of the workshop was to make presentations on current research activities and accomplishments and to assess progress in the area of sonic boom since the program was initiated in FY-90. Twenty-nine papers were presented during the 2-1/2 day workshop. Attendees included representatives from academia, industry, and government who are actively involved in sonic-boom research. Volume 2 contains papers related to low sonic-boom design and analysis using both linear theory and higher order computational fluid dynamics (CFD) methods.

  17. The Effect of Sonic Booms on Earthquake Warning Systems

    NASA Technical Reports Server (NTRS)

    Wurman, Gilead; Haering, Edward A, Jr.; Price, Michael J.

    2011-01-01

    Several aerospace companies are designing quiet supersonic business jets for service over the United States. These aircraft have the potential to increase the occurrence of mild sonic booms across the country. This leads to interest among earthquake warning (EQW) developers and the general seismological community in characterizing the effect of sonic booms on seismic sensors in the field, their potential impact on EQW systems, and means of discriminating their signatures from those of earthquakes. The SonicBREWS project (Sonic Boom Resistant Earthquake Warning Systems) is a collaborative effort between Seismic Warning Systems, Inc. (SWS) and NASA Dryden Flight Research Center. This project aims to evaluate the effects of sonic booms on EQW sensors. The study consists of exposing high-sample-rate (1000 sps) triaxial accelerometers to sonic booms with overpressures ranging from 10 to 600 Pa in the free field and the built environment. The accelerometers record the coupling of the sonic boom to the ground and surrounding structures, while microphones record the acoustic wave above ground near the sensor. Sonic booms are broadband signals with more high-frequency content than earthquakes. Even a 1000 sps accelerometer will produce a significantly aliased record. Thus the observed peak ground velocity is strongly dependent on the sampling rate, and increases as the sampling rate is reduced. At 1000 sps we observe ground velocities that exceed those of P-waves from ML 3 earthquakes at local distances, suggesting that sonic booms are not negligible for EQW applications. We present the results of several experiments conducted under SonicBREWS showing the effects of typical-case low amplitude sonic booms and worst-case high amplitude booms. We show the effects of various sensor placements and sensor array geometries. Finally, we suggest possible avenues for discriminating sonic booms from earthquakes for the purposes of EQW.

  18. Optimum configurations for bangless sonic booms.

    NASA Technical Reports Server (NTRS)

    Hayes, W. D.; Weiskope, F. B., Jr.

    1972-01-01

    A number of optimization problems are posed and solved for supersonic aircraft flight subject to the condition that a shock wave appears only incipiently in the sonic boom signal at a given point. The principal result is one giving the maximum effective gross weight of an aircraft of given effective length under given flight conditions. The calculus of variations with inequality constraints is used, with the novel features of a non-local isoperimetric relation and of only an upper bound on a control variable.

  19. Recent Progress on Sonic Boom Research at NASA

    NASA Technical Reports Server (NTRS)

    Loubeau, Alexandra

    2012-01-01

    Sonic boom research conducted at NASA through the Supersonics Project of the Fundamental Aeronautics Program is oriented toward understanding the potential impact of sonic boom noise on communities from new low-boom supersonic aircraft designs. Encompassing research in atmospheric propagation, structural response, and human response, NASA research contributes to knowledge in key areas needed to support development of a new noise-based standard for supersonic aircraft certification. Partnerships with several industry, government, and academic institutions have enabled the recent execution of several acoustic field studies on sonic booms. An overview of recent activities funded by NASA includes: focus boom model development and experimental validation, field experiments of structural transmission of sonic booms into large buildings, and low boom community response testing.

  20. CFD Analysis of Nozzle Jet Plume Effects on Sonic Boom Signature

    NASA Technical Reports Server (NTRS)

    Bui, Trong T.

    2009-01-01

    An axisymmetric full Navier-Stokes computational fluid dynamics study is conducted to examine nozzle exhaust jet plume effects on the sonic boom signature of a supersonic aircraft. A simplified axisymmetric nozzle geometry, representative of the nozzle on the NASA Dryden NF-15B Lift and Nozzle Change Effects on Tail Shock research airplane, is considered. The computational fluid dynamics code is validated using available wind-tunnel sonic boom experimental data. The effects of grid size, spatial order of accuracy, grid type, and flow viscosity on the accuracy of the predicted sonic boom pressure signature are quantified. Grid lines parallel to the Mach wave direction are found to give the best results. Second-order accurate upwind methods are required as a minimum for accurate sonic boom simulations. The highly underexpanded nozzle flow is found to provide significantly more reduction in the tail shock strength in the sonic boom N-wave pressure signature than perfectly expanded and overexpanded nozzle flows. A tail shock train in the sonic boom signature is observed for the highly underexpanded nozzle flow. Axisymmetric computational fluid dynamics simulations show the flow physics inside the F-15 nozzle to be nonisentropic and complex. Although the one-dimensional isentropic nozzle plume results look reasonable, they fail to capture the sonic boom shock train in the highly underexpanded nozzle flow.

  1. 14 CFR 91.817 - Civil aircraft sonic boom.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Civil aircraft sonic boom. 91.817 Section 91.817 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Operating Noise Limits § 91.817 Civil aircraft sonic boom. (a) No...

  2. Audiometric effects of simulated sonic booms in guinea pigs

    NASA Astrophysics Data System (ADS)

    Reinis, S.; Weiss, D. S.; Featherstone, J. W.; Tsaros, C.

    1987-03-01

    Changes of hearing thresholds have been studied in guinea pigs following exposure to 100 simulated sonic booms. Simulated sonic booms increased the hearing thresholds at frequencies above 30 kHz. The only early structural change observed was an appearance of a small blood clot in the scala tympani of the basal turn of the cochlea. Although these changes may be specific for small laboratory animals only, they indicate that caution is necessary in exposing people to repeated or intense sonic booms. Also, the data indicate that, following the exposure to the sonic booms, the high frequency hearing is influenced first. Therefore, audiometric testing following the sonic boom exposure should not be limited to the routine audiometric curve ending at 8 kHz.

  3. High-Speed Research: Sonic Boom, Volume 1

    NASA Technical Reports Server (NTRS)

    Edwards, Thomas A. (Editor)

    1994-01-01

    The second High-Speed Research Program Sonic Boom Workshop was held at NASA Ames Research Center May 12-14, 1993. The workshop was organized into three sessions dealing with atmospheric propagation, acceptability, and configuration design. Volume 1 includes papers on atmospheric propagation and acceptability studies. Significant progress is noted in these areas in the time since the previous workshop a year earlier. In particular, several papers demonstrate an improved capability to model the effect of atmospheric turbulence on sonic booms. This is a key issue in determining the stability and acceptability of shaped sonic booms. In the area of acceptability, the PLdB metric has withstood considerable scrutiny and is validated as a loudness metric for a wide variety of sonic boom shapes. The differential loudness of asymmetric sonic booms is better understood, too.

  4. Two HSCT Mach 1.7 low sonic boom designs

    NASA Technical Reports Server (NTRS)

    Haglund, George T.; Ogg, Steven S.

    1992-01-01

    The objective of this study was to provide low sonic boom concepts, geometry, and analysis to support wind tunnel model designs. Within guidelines provided by NASA, two High Speed Civil Transport (HSCT) configurations were defined with reduced sonic boom that have low drag, high payload, and good performance. To provide information for assessing the feasibility of reduced sonic boom operation, the two designs were analyzed in terms of their sonic boom characteristics, as well as aerodynamics, weight and balance, and performance characteristics. Low drag and high payload were achieved, but both of the blended arrow-wing configurations have deficiencies in high lift capability, fuel volume, wing loading, balance, and takeoff gross weight. Further refinement of the designs is needed to better determine the commercial viability of low boom operation. To help in assessing low boom design technology, the two configurations were defined as wind tunnel models with altered aft-bodies for the wind tunnel sting mounting system.

  5. Potential for Sonic Boom Reduction of the Boeing HSCT

    NASA Technical Reports Server (NTRS)

    Haglund, George T.

    1999-01-01

    The HSR sonic boom technology program includes a goal of reducing the objectionable aspects of sonic boom. Earlier HSCT sonic boom studies considered achieving significant sonic boom reduction by the use of arrow-wing planforms and detailed shaping of the airplane to produce shaped waveforms (non N-waves) at the ground. While these design efforts were largely successful, the added risk and cost of the airplanes were judged to be unacceptable. The objective of the current work is to explore smaller configuration refinements that could lead to reduced sonic boom impact, within design and operational constraints. A somewhat modest target of 10% reduction in sonic boom maximum overpressure was selected to minimize the effect on the configuration performance. This work was a joint NASA/Industry effort, utilizing the respective strengths of team members at Boeing, NASA Langley, and NASA Ames. The approach used was to first explore a wide range of modifications and airplane characteristics for their effects on sonic boom and drag, using classical Modified Linear Theory (MLT) methods. CFD methods were then used to verify promising, modifications and to analyze modifications for which the MLT methods were not appropriate. The tea m produced a list of configuration changes with their effects on sonic boom and, in some cases, an estimate of the drag penalty. The most promising modifications were applied to produce a boom-softened derivative of the baseline Boeing High Speed Civil Transport (HSCT) configuration. This boom-softened configuration was analyzed in detail for the reduce sonic boom impact and also for the effect of the configuration modifications on drag, weight, and overall performance relative to the baseline.

  6. Sonic boom (human response and atmospheric effects) outdoor-to-indoor response to minimized sonic booms

    NASA Technical Reports Server (NTRS)

    Brown, David; Sutherland, Louis C.

    1992-01-01

    The preferred descriptor to define the spectral content of sonic booms is the Sound Exposure Spectrum Level, LE(f). This descriptor represents the spectral content of the basic noise descriptors used for describing any single event--the Sound Exposure Level, LE. The latter is equal to ten times the logarithms, to the base ten, of the integral, over the duration of the event, of the square of the instantaneous acoustic pressure, divided by the square of the reference pressure, 20 micro-Pa. When applied to the evaluation of community response to sonic booms, it is customary to use the so-called C-Weighted Sound Exposure Level, LCE, for which the frequency content of the instantaneous acoustic pressure is modified by the C-Weighting curve.

  7. Subjective loudness of "minimized" sonic boom waveforms.

    PubMed

    Niedzwiecki, A; Ribner, H S

    1978-12-01

    For very long supersonic aircraft the "midfield" sonic boom signature may not have evolved fully into an N wave at ground level. Thus in current boom minimization techniques the shape of the aircraft may be tailored to optimize this midfield wave form for reduced subjective loudness. The present investigation tests a family of "flat-top" waveforms cited by Darden: all but one have a front shock height (deltapSH) less than the peak amplitude (deltapMAX). For equal subjective loudness, "flat top" vs N wave (peak overpressure deltapN), the peak amplitude of the "flat top" signature was found to be substantially higher than that of the N wave; thus for equal peak amplitude the "flat-top" signature was quieter. The results for equal loudness were well fitted by an emperical law deltapSH + 0.11deltapMAX = deltapN; the equivalence shows how the front shock amplitude (deltapSH) dominates the loudness. All this was found compatible with predictions by the method of Johnson and Robinson. PMID:739097

  8. Quiet Sonic Booms: A NASA and Industry Progress Report

    NASA Technical Reports Server (NTRS)

    Larson, David Nils; Martin, Roy; Haering, Edward A.

    2011-01-01

    The purpose of this Oral Presentation is to present a progress report on NASA and Industry efforts related to Quiet Sonic Boom Program activities. This presentation will review changes in aircraft shaping to produce quiet supersonic booms and associated supersonic flight test methods and results. In addition, new flight test profiles have been recently developed that have allowed for the generation of sonic booms of varying intensity. These new flight test profiles have allowed for ground testing of the response of various building structures to sonic booms and the associated public acceptability to various sonic boom intensities. The new flight test profiles and associated ground measurement test methods will be reviewed. Finally, this Oral Presentation will review the International Regulatory requirements that would be involved to change aviation regulation and allow for overland quiet supersonic flight.

  9. Supersonic civil airplane study and design: Performance and sonic boom

    NASA Technical Reports Server (NTRS)

    Cheung, Samson

    1995-01-01

    Since aircraft configuration plays an important role in aerodynamic performance and sonic boom shape, the configuration of the next generation supersonic civil transport has to be tailored to meet high aerodynamic performance and low sonic boom requirements. Computational fluid dynamics (CFD) can be used to design airplanes to meet these dual objectives. The work and results in this report are used to support NASA's High Speed Research Program (HSRP). CFD tools and techniques have been developed for general usages of sonic boom propagation study and aerodynamic design. Parallel to the research effort on sonic boom extrapolation, CFD flow solvers have been coupled with a numeric optimization tool to form a design package for aircraft configuration. This CFD optimization package has been applied to configuration design on a low-boom concept and an oblique all-wing concept. A nonlinear unconstrained optimizer for Parallel Virtual Machine has been developed for aerodynamic design and study.

  10. A loudness calculation procedure applied to shaped sonic booms

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P.; Sullivan, Brenda M.

    1991-01-01

    Described here is a procedure that can be used to calculate the loudness of sonic booms. The procedure is applied to a wide range of sonic booms, both classical N-waves and a variety of other shapes of booms. The loudness of N-waves is controlled by overpressure and the associated rise time. The loudness of shaped booms is highly dependent on the characteristics of the initial shock. A comparison of the calculated loudness values indicates that shaped booms may have significantly reduced loudness relative to N-waves having the same peak overpressure. This result implies that a supersonic transport designed to yield minimized sonic booms may be substantially more acceptable than an unconstrained design.

  11. SCAMP: Rapid Focused Sonic Boom Waypoint Flight Planning Methods, Execution, and Results

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.; Cliatt, Larry J., II; Delaney, Michael M., Jr.; Plotkin, Kenneth J.; Maglieri, Domenic J.; Brown, Jacob C.

    2012-01-01

    Successful execution of the flight phase of the Superboom Caustic Analysis and Measurement Project (SCAMP) required accurate placement of focused sonic booms on an array of prepositioned ground sensors. While the array was spread over a 10,000-ft-long area, this is a relatively small region when considering the speed of a supersonic aircraft and sonic boom ray path variability due to shifting atmospheric conditions and aircraft trajectories. Another requirement of the project was to determine the proper position for a microphone-equipped motorized glider to intercept the sonic boom caustic, adding critical timing to the constraints. Variability in several inputs to these calculations caused some shifts of the focus away from the optimal location. Reports of the sonic booms heard by persons positioned amongst the array were used to shift the focus closer to the optimal location for subsequent passes. This paper describes the methods and computations used to place the focused sonic boom on the SCAMP array and gives recommendations for their accurate placement by future quiet supersonic aircraft. For the SCAMP flights, 67% of the foci were placed on the ground array with measured positions within a few thousand feet of computed positions. Among those foci with large caustic elevation angles, 96% of foci were placed on the array, and measured positions were within a few hundred feet of computed positions. The motorized glider captured sonic booms on 59% of the passes when the instrumentation was operating properly.

  12. Numerical Predictions of Sonic Boom Signatures for a Straight Line Segmented Leading Edge Model

    NASA Technical Reports Server (NTRS)

    Elmiligui, Alaa A.; Wilcox, Floyd J.; Cliff, Susan; Thomas, Scott

    2012-01-01

    A sonic boom wind tunnel test was conducted on a straight-line segmented leading edge (SLSLE) model in the NASA Langley 4- by 4- Foot Unitary Plan Wind Tunnel (UPWT). The purpose of the test was to determine whether accurate sonic boom measurements could be obtained while continuously moving the SLSLE model past a conical pressure probe. Sonic boom signatures were also obtained using the conventional move-pause data acquisition method for comparison. The continuous data acquisition approach allows for accurate signatures approximately 15 times faster than a move-pause technique. These successful results provide an incentive for future testing with greatly increased efficiency using the continuous model translation technique with the single probe to measure sonic boom signatures. Two widely used NASA codes, USM3D (Navier-Stokes) and CART3D-AERO (Euler, adjoint-based adaptive mesh), were used to compute off-body sonic boom pressure signatures of the SLSLE model at several different altitudes below the model at Mach 2.0. The computed pressure signatures compared well with wind tunnel data. The effect of the different altitude for signature extraction was evaluated by extrapolating the near field signatures to the ground and comparing pressure signatures and sonic boom loudness levels.

  13. CFD Analysis of Nozzle Jet Plume Effects on Sonic Boom Signature

    NASA Technical Reports Server (NTRS)

    Bui, Trong T.

    2009-01-01

    A computational fluid dynamics study is conducted to examine nozzle exhaust jet plume effects on the Sonic boom signature of a supersonic aircraft. A simplified axisymmetric nozzle geometry, representative of the nozzle on the NASA Dryden NF-15B Lift and Nozzle Change Effects on Tail Shock research airplane, is considered. The computational fluid dynamics code is validated using available wind-tunnel sonic boom experimental data. The effects of grid size, spatial order of accuracy. grid type, and flow viscosity on the accuracy of the predicted sonic boom pressure signature are quantified. Grid lines parallel to the Mach wave direction are found to give the best results. Second-order accurate upwind methods are required as a minimum for accurate sonic boom simulations. The highly underexpanded nozzle flow is found to provide significantly more reduction in the tail shock strength in the sonic boom N-wave pressure signature than perfectly expanded and overexpanded nozzle flows. A tail shock train in the sonic boom signature is observed for the highly underexpanded nozzle flow. Axisymmetric computational fluid dynamics simulations show the flow physics inside the F-15 nozzle to be nonisentropic and complex.

  14. Sonic Boom Minimization Efforts on Boeing HSCT Baseline

    NASA Technical Reports Server (NTRS)

    Cheung, Samson H.; Fouladi, Kamran; Haglund, George; Tu, Eugene

    1999-01-01

    A team was formed to tackle the sonic boom softening issues of the current Boeing HSCT design. The team consisted of personnel from NASA Ames, NASA Langley, and Boeing company. The work described in this paper was done when the first author was at NASA Ames Research Center. This paper presents the sonic boom softening work on two Boeing High Speed Civil Transport (HSCT) baseline configurations, Reference-H and Boeing-1122. This presentation can be divided into two parts: parametric studies and sonic boom minimization by CFD optimization routines.

  15. State of the art of sonic boom modeling.

    PubMed

    Plotkin, Kenneth J

    2002-01-01

    Based on fundamental theory developed through the 1950s and 1960s, sonic boom modeling has evolved into practical tools. Over the past decade, there have been requirements for design tools for an advanced supersonic transport, and for tools for environmental assessment of various military and aerospace activities. This has resulted in a number of advances in the understanding of the physics of sonic booms, including shock wave rise times, propagation through turbulence, and blending sonic boom theory with modern computational fluid dynamics (CFD) aerodynamic design methods. This article reviews the early fundamental theory, recent advances in theory, and the application of these advances to practical models. PMID:11837958

  16. Field measurements of sonic boom penetration into the ocean

    PubMed

    Sohn; Vernon; Hildebrand; Webb

    2000-06-01

    Six sonic booms, generated by F-4 aircraft under steady flight at a range of altitudes (610-6100 m) and Mach numbers (1.07-1.26), were measured just above the air/sea interface, and at five depths in the water column. The measurements were made with a vertical hydrophone array suspended from a small spar buoy at the sea surface, and telemetered to a nearby research vessel. The sonic boom pressure amplitude decays exponentially with depth, and the signal fades into the ambient noise field by 30-50 m, depending on the strength of the boom at the sea surface. Low-frequency components of the boom waveform penetrate significantly deeper than high frequencies. Frequencies greater than 20 Hz are difficult to observe at depths greater than about 10 m. Underwater sonic boom pressure measurements exhibit excellent agreement with predictions from analytical theory, despite the assumption of a flat air/sea interface. Significant scattering of the sonic boom signal by the rough ocean surface is not detected. Real ocean conditions appear to exert a negligible effect on the penetration of sonic booms into the ocean unless steady vehicle speeds exceed Mach 3, when the boom incidence angle is sufficient to cause scattering on realistic open ocean surfaces. PMID:10875353

  17. Field Measurements of Sonic Boom Penetration Into the Ocean

    NASA Technical Reports Server (NTRS)

    Sohn, R. A.; Vernon, F.; Hildebrand, J. A.; Webb, S. C.; Shepherd, Kevin (Technical Monitor)

    2000-01-01

    Six sonic booms, generated by F-4 aircraft under steady fight at a range of altitudes (610-6100 m) and Mach numbers (1.07-1.26), were measured just above the air/sea interface, and at five depths in the water column. The measurements were made with a vertical hydrophone array suspended from a small spar buoy at the sea surface, and telemetered to a nearby research vessel. The sonic boom pressure amplitude decays exponentially with depth, and the signal fades into the ambient noise field by 30-50 in, depending on the strength of the boom at the sea surface. Low-frequency components of the boom waveform penetrate significantly deeper than high frequencies. Frequencies greater than 20 Hz are difficult to observe at depths greater than about 10 m. Underwater sonic boom pressure measurements exhibit excellent agreement with predictions from analytical theory, despite the assumption of a flat air/sea interface. Significant scattering of the sonic boom signal by the rough ocean surface is not detected. Real ocean conditions appear to exert a negligible effect on the penetration of sonic booms into the ocean unless steady vehicle speeds exceed Mach 3, when the boom incidence angle is sufficient to cause scattering on realistic open ocean surfaces.

  18. Recent laboratory studies of loudness and annoyance to sonic booms

    NASA Technical Reports Server (NTRS)

    Leatherwood, Jack D.; Sullivan, Brenda M.

    1993-01-01

    NASA Langley Research Center is supporting NASA High-Speed Research Program efforts to develop an updated technology base for future high-speed civil transport aircraft. Part of this effort involves (a) quantification of loudness and annoyance benefits due to sonic boom shaping and (b) determination of boom exposures acceptable to the public. Langley is conducting a series of laboratory studies to investigate in detail the subjective reactions to a wide range of shaped sonic boom signatures and to examine several metrics as estimators of sonic boom subjective effects. Results from several of these studies, as well as results obtained by other investigators, demonstrated that substantial reductions in the loudness of sonic booms can be achieved by careful shaping of the boom signatures. Recent Langley studies extended this work to include: (a) quantification of subjective effects due to booms heard indoors, (b) determination of subjective reactions due to ground-reflected booms, and (c) determination of subjective reactions to simulator reproductions of booms recently at White Sands Missile Range.

  19. A summary of XB-70 sonic boom signature data

    NASA Astrophysics Data System (ADS)

    Maglieri, Domenic J.; Sothcott, Victor E.; Keefer, Thomas N., Jr.

    1992-04-01

    A compilation is provided of measured sonic boom signature data derived from 39 supersonic flights (43 passes) of the XB-70 airplane over the Mach number range of 1.11 to 2.92 and an altitude range of 30500 to 70300 ft. These tables represent a convenient hard copy version of available electronic files which include over 300 digitized sonic boom signatures with their corresponding spectra. Also included in the electronic files is information regarding ground track position, aircraft operating conditions, and surface and upper air weather observations for each of the 43 supersonic passes. In addition to the sonic boom signature data, a description is also provided of the XB-70 data base that was placed on electronic files along with a description of the method used to scan and digitize the analog/oscillograph sonic boom signature time histories. Such information is intended to enhance the value and utilization of the electronic files.

  20. A summary of XB-70 sonic boom signature data

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Sothcott, Victor E.; Keefer, Thomas N., Jr.

    1992-01-01

    A compilation is provided of measured sonic boom signature data derived from 39 supersonic flights (43 passes) of the XB-70 airplane over the Mach number range of 1.11 to 2.92 and an altitude range of 30500 to 70300 ft. These tables represent a convenient hard copy version of available electronic files which include over 300 digitized sonic boom signatures with their corresponding spectra. Also included in the electronic files is information regarding ground track position, aircraft operating conditions, and surface and upper air weather observations for each of the 43 supersonic passes. In addition to the sonic boom signature data, a description is also provided of the XB-70 data base that was placed on electronic files along with a description of the method used to scan and digitize the analog/oscillograph sonic boom signature time histories. Such information is intended to enhance the value and utilization of the electronic files.

  1. Sonic boom prediction and minimization using computational fluid dynamics

    NASA Technical Reports Server (NTRS)

    Edwards, Thomas A.; Hicks, Raymond; Cheung, Samson; Cliff-Hovey, Susan; Madson, Mike; Mendoza, Joel

    1992-01-01

    This paper describes the NASA ARC program in sonic boom prediction methodologies. This activity supports NASA's High Speed Research Program (HSRP). An overview of the program, recent results, conclusions, and current effort will be given. This effort complements research in sonic boom acceptability and validation being conducted at LaRC and ARC. The goals of the sonic boom element are as follows: to establish a predictive capability for sonic booms generated by High-Speed Civil Transport (HSCT) concepts; to establish guidelines of acceptability for supersonic overland flight; and to validate these findings with wind tunnel and flight tests. The cumulative result of these efforts will be an assessment of economic viability for supersonic transportation. This determination will ultimately be made by the aerospace industry.

  2. Subjective Response to Simulated Sonic Booms in Homes

    NASA Technical Reports Server (NTRS)

    McCurdy, David A.; Brown, Sherilyn A.

    1996-01-01

    One of the environmental issues affecting the development of a second-generation supersonic commercial transport is the impact of sonic booms on people. Aircraft designers are attempting to design the transport to produce sonic boom signatures that will have minimum impact on the public. Current supersonic commercial aircraft produce an 'N-wave' sonic boom pressure signature that is considered unacceptable by the public. This has resulted in first-generation supersonic transports being banned from flying supersonic over land in the United States, a severe economic constraint. By tailoring aircraft volume and lift distributions, designers hope to produce sonic boom signatures having specific shapes other than 'N-wave' that may be more acceptable to the public. As part of the effort to develop a second-generation supersonic commercial transport, Langley Research Center is conducting research to study people's subjective response to sonic booms. As part of that research, a system was developed for performing studies of the subjective response of people to the occurrence of simulated sonic booms in their homes. The In-Home Noise Generation/Response System (IHONORS) provides a degree of situational realism not available in the laboratory and a degree of control over the noise exposure not found in community surveys. The computer-controlled audio system generates the simulated sonic booms, measures the noise levels, and records the subjects' ratings and can be placed and operated in individual homes for extended periods of time. The system was used to conduct an in-home study of subjective response to simulated sonic booms. The primary objective of the study was to determine the effect on annoyance of the number of sonic boom occurrences in a realistic environment. The effects on annoyance of several other parameters were also examined. Initially, data analyses were based on all the data collected. However, further analyser found that test subjects adapted to the sonic

  3. Initial Results from the Variable Intensity Sonic Boom Database

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.; Cliatt, Larry J., II; Gabrielson, Thomas; Sparrow, Victor W.; Locey, Lance L.; Bunce, Thomas J.

    2008-01-01

    43 sonic booms generated (a few were evanescent waves) a) Overpressures of 0.08 to 2.20 lbf/sq ft; b) Rise-times of about 0.7 to 50 ms. Objectives: a) Structural response of a house of modern construction; b) Sonic boom propagation code validation. Approach: a) Measure shockwave directionality; b) Determine effect of height above ground on acoustic level; c) Generate atmospheric turbulence filter functions.

  4. Assessment of Near-Field Sonic Boom Simulation Tools

    NASA Technical Reports Server (NTRS)

    Casper, J. H.; Cliff, S. E.; Thomas, S. D.; Park, M. A.; McMullen, M. S.; Melton, J. E.; Durston, D. A.

    2008-01-01

    A recent study for the Supersonics Project, within the National Aeronautics and Space Administration, has been conducted to assess current in-house capabilities for the prediction of near-field sonic boom. Such capabilities are required to simulate the highly nonlinear flow near an aircraft, wherein a sonic-boom signature is generated. There are many available computational fluid dynamics codes that could be used to provide the near-field flow for a sonic boom calculation. However, such codes have typically been developed for applications involving aerodynamic configuration, for which an efficiently generated computational mesh is usually not optimum for a sonic boom prediction. Preliminary guidelines are suggested to characterize a state-of-the-art sonic boom prediction methodology. The available simulation tools that are best suited to incorporate into that methodology are identified; preliminary test cases are presented in support of the selection. During this phase of process definition and tool selection, parallel research was conducted in an attempt to establish criteria that link the properties of a computational mesh to the accuracy of a sonic boom prediction. Such properties include sufficient grid density near shocks and within the zone of influence, which are achieved by adaptation and mesh refinement strategies. Prediction accuracy is validated by comparison with wind tunnel data.

  5. Sonic-boom minimization with nose-bluntness relaxation

    NASA Technical Reports Server (NTRS)

    Darden, C. M.

    1979-01-01

    A procedure which provides sonic-boom-minimizing equivalent area distributions for supersonic cruise conditions is described. This work extends previous analyses to permit relaxation of the extreme bluntness required by conventional low-boom shapes and includes propagation in a real atmosphere. The procedure provides area distributions which minimize either shock strength or overpressure.

  6. Subjective response to simulated sonic booms with ground reflections

    NASA Technical Reports Server (NTRS)

    Sullivan, B. M.; Leatherwood, J. D.

    1993-01-01

    The Sonic Boom Simulator at NASA LaRC was used for the following: (1) quantify subjective loudness of simulated composite sonic booms, each of which was comprised of a simulated direct (non-reflected) boom combined with a simulated reflection of the direct boom; and (2) evaluate several metrics as estimators of loudness for these composite booms. The direct booms consisted of selected N-wave and minimized signatures having front-shock rise times of 3, 6, and 9 milliseconds and durations of 300 milliseconds. Delay times of the reflected booms ranged from 0 to 12 milliseconds. Subjective loudness results indicated that composite booms formed using reflections with non-zero delay times were generally rated as being less loud than composite booms containing non-delayed reflections. The largest reductions in loudness occurred when delay times were equal to the front shock rise times of the direct booms and were, in some cases, equivalent to reductions in Perceived Level of 6 to 7 dB. Results also showed Perceived Level to be an effective metric for assessing subjective loudness effects for the composite signatures. This was confirmed by statistical analysis, which showed that, for equal Perceived Level, no significant differences existed between the subjective loudness responses to composite booms containing reflections with zero delay and those containing reflections with non-zero delays.

  7. Overview of NASA human response to sonic boom program

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P.

    1992-01-01

    For some routes the ability to fly at supersonic speeds over land as well as over water would greatly enhance the time benefit to the passenger. It would also increase the productivity and economic viability of the aircraft. There are no reliable guidelines which can be used to determine a sonic boom exposure which would be acceptable for overland supersonic flight. In addition to the peak pressure of the sonic boom, the detailed shape of the signature will also influence the perception, and therefore the community response, to sonic boom exposures. Initially, the program aims to develop the capability to predict human response to individual sonic booms. This will enable a quantitative assessment of the benefit of 'low boom' aircraft configurations and will also serve to guide the design of the aircraft and its operating conditions. This capability will form the foundation of studies to determine the relationship between sonic boom exposure and community response. Only then will it be possible to assess the feasibility of acceptable overland supersonic flight.

  8. A New Simulator for Assessing Subjective Effects of Sonic Booms

    NASA Technical Reports Server (NTRS)

    Leatherwood, Jack D.; Shepherd, Kevin P.; Sullivan, Brenda M.

    1991-01-01

    A man rated and computer driven sonic boom simulator which has been constructed and placed in operational use at NASA-Langley is described. The simulator is used to study human subjective reactions to sonic booms and has the capability of producing a wide range of signatures under controlled conditions. Results are presented to illustrate the capability of the simulator to generate user specified N-wave and shaped booms having rise times as low as 0.5 milliseconds and peak overpressures up to 191 Pa (4 psf). The validity of the simulator as a lab research tool for studying human subjective response to sonic booms was demonstrated by successful completion of a preliminary test designed to compare loudness of N-wave sonic booms with results obtained by other investigators. Excellent agreement of the preliminary test data with existing data was observed. This provided confidence in the experimental methodology and established the simulator as a viable tool for performing detailed evaluations of sonic boom loudness and acceptability within the lab. environment.

  9. A Compilation of Space Shuttle Sonic Boom Measurements

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Henderson, Herbert R.; Massey, Steven J.; Stansbery, Eugene G.

    2011-01-01

    Sonic boom measurements have been obtained on 26 flights of the Space Shuttle system beginning with the launch of STS-1 on April 12, 1981, to the reentry-descent of STS-41 into EAFB on Oct. 10, 1990. A total of 23 boom measurements were acquired within the focus region off the Florida coast during 3 STS launch-ascents and 113 boom measurements were acquired during 23 STS reentry-descent to landing into Florida and California. Sonic boom measurements were made under, and lateral to, the vehicle ground track and cover the Mach-altitude range of about 1.3 to 23 and 54,000 feet to 243,000 feet, respectively. Vehicle operational data, flight profiles and weather data were also gathered during the flights. This STS boom database is contained in 26 documents, some are formal and referenceable but most internal documents. Another 38 documents, also non-referenceable, contain predicted sonic boom footprints for reentry-descent flights on which no measurements were made. The purpose of this report is to provide an overview of the STS sonic boom database and summarize the main findings.

  10. Design of Rail Instrumentation for Wind Tunnel Sonic Boom Measurements and Computational-Experimental Comparisons

    NASA Technical Reports Server (NTRS)

    Cliff, Susan E.; Elmiligui, A.; Aftosmis, M.; Morgenstern, J.; Durston, D.; Thomas, S.

    2012-01-01

    An innovative pressure rail concept for wind tunnel sonic boom testing of modern aircraft configurations with very low overpressures was designed with an adjoint-based solution-adapted Cartesian grid method. The computational method requires accurate free-air calculations of a test article as well as solutions modeling the influence of rail and tunnel walls. Specialized grids for accurate Euler and Navier-Stokes sonic boom computations were used on several test articles including complete aircraft models with flow-through nacelles. The computed pressure signatures are compared with recent results from the NASA 9- x 7-foot Supersonic Wind Tunnel using the advanced rail design.

  11. Analysis of Nozzle Jet Plume Effects on Sonic Boom Signature

    NASA Technical Reports Server (NTRS)

    Bui, Trong

    2010-01-01

    An axisymmetric full Navier-Stokes computational fluid dynamics (CFD) study was conducted to examine nozzle exhaust jet plume effects on the sonic boom signature of a supersonic aircraft. A simplified axisymmetric nozzle geometry, representative of the nozzle on the NASA Dryden NF-15B Lift and Nozzle Change Effects on Tail Shock (LaNCETS) research airplane, was considered. The highly underexpanded nozzle flow is found to provide significantly more reduction in the tail shock strength in the sonic boom N-wave pressure signature than perfectly expanded and overexpanded nozzle flows. A tail shock train in the sonic boom signature, similar to what was observed in the LaNCETS flight data, is observed for the highly underexpanded nozzle flow. The CFD results provide a detailed description of the nozzle flow physics involved in the LaNCETS nozzle at different nozzle expansion conditions and help in interpreting LaNCETS flight data as well as in the eventual CFD analysis of a full LaNCETS aircraft. The current study also provided important information on proper modeling of the LaNCETS aircraft nozzle. The primary objective of the current CFD research effort was to support the LaNCETS flight research data analysis effort by studying the detailed nozzle exhaust jet plume s imperfect expansion effects on the sonic boom signature of a supersonic aircraft. Figure 1 illustrates the primary flow physics present in the interaction between the exhaust jet plume shock and the sonic boom coming off of an axisymmetric body in supersonic flight. The steeper tail shock from highly expanded jet plume reduces the dip of the sonic boom N-wave signature. A structured finite-volume compressible full Navier-Stokes CFD code was used in the current study. This approach is not limited by the simplifying assumptions inherent in previous sonic boom analysis efforts. Also, this study was the first known jet plume sonic boom CFD study in which the full viscous nozzle flow field was modeled, without

  12. Integration of Off-Track Sonic Boom Analysis in Conceptual Design of Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Ordaz, Irian; Li, Wu

    2011-01-01

    A highly desired capability for the conceptual design of aircraft is the ability to rapidly and accurately evaluate new concepts to avoid adverse trade decisions that may hinder the development process in the later stages of design. Evaluating the robustness of new low-boom concepts is important for the conceptual design of supersonic aircraft. Here, robustness means that the aircraft configuration has a low-boom ground signature at both under- and off-track locations. An integrated process for off-track boom analysis is developed to facilitate the design of robust low-boom supersonic aircraft. The integrated off-track analysis can also be used to study the sonic boom impact and to plan future flight trajectories where flight conditions and ground elevation might have a significant effect on ground signatures. The key enabler for off-track sonic boom analysis is accurate computational fluid dynamics (CFD) solutions for off-body pressure distributions. To ensure the numerical accuracy of the off-body pressure distributions, a mesh study is performed with Cart3D to determine the mesh requirements for off- body CFD analysis and comparisons are made between the Cart3D and USM3D results. The variations in ground signatures that result from changes in the initial location of the near-field waveform are also examined. Finally, a complete under- and off-track sonic boom analysis is presented for two distinct supersonic concepts to demonstrate the capability of the integrated analysis process.

  13. Atmospheric effects on sonic boom: A program review

    NASA Astrophysics Data System (ADS)

    McAninch, Gerry L.

    1992-04-01

    The program goals were determined after consideration of the weaknesses in our understanding of atmospheric effects on sonic boom waveforms left in the wake of the cancellation of the U.S. SST in the 70's and the advancements in acoustics and atmospheric science since that time. For example, a considerable body of knowledge on molecular absorption has built up in the acoustics community over the last 15 years and this has not been incorporated into the sonic boom theory. Further, it was felt that the understanding of atmospheric turbulence had also advanced considerably during that time period. Therefore, key elements of the current program are the development of an improved atmospheric absorption model and an improved atmospheric turbulence model. The advances made in computer power over the last 15 years were also considered, and will be utilized to remove restrictions on the analytical model for turbulence effects on sonic boom waveforms. Although the majority of disturbing sonic booms will not occur at focuses or caustics, it was felt that this was an area that required further understanding, thus it will be looked into. Finally, in order to insure that the current effort, which is basically analytical in nature, retains a firm grasp on reality, a data base of sonic boom waveforms and associated weather data is being compiled, and a set of scale model experiments is being planned to guide the overall efforts.

  14. Atmospheric effects on sonic boom: A program review

    NASA Technical Reports Server (NTRS)

    Mcaninch, Gerry L.

    1992-01-01

    The program goals were determined after consideration of the weaknesses in our understanding of atmospheric effects on sonic boom waveforms left in the wake of the cancellation of the U.S. SST in the 70's and the advancements in acoustics and atmospheric science since that time. For example, a considerable body of knowledge on molecular absorption has built up in the acoustics community over the last 15 years and this has not been incorporated into the sonic boom theory. Further, it was felt that the understanding of atmospheric turbulence had also advanced considerably during that time period. Therefore, key elements of the current program are the development of an improved atmospheric absorption model and an improved atmospheric turbulence model. The advances made in computer power over the last 15 years were also considered, and will be utilized to remove restrictions on the analytical model for turbulence effects on sonic boom waveforms. Although the majority of disturbing sonic booms will not occur at focuses or caustics, it was felt that this was an area that required further understanding, thus it will be looked into. Finally, in order to insure that the current effort, which is basically analytical in nature, retains a firm grasp on reality, a data base of sonic boom waveforms and associated weather data is being compiled, and a set of scale model experiments is being planned to guide the overall efforts.

  15. CFD prediction of the near-field sonic boom environment for two low boom HSCT configurations. [High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Siclari, M. J.; Darden, C. M.

    1991-01-01

    Current efforts to reduce the sonic boom of a future High Speed Civil Transport (HSCT) by careful shaping have led to the need for more accurate predictions of the near-field flow conditions of the configuration. A fully three-dimensional Euler finite volume code is used to predict sonic boom pressure signatures for two low boom concepts - one designed to cruise at Mach 2 and the other at Mach 3. Calculations were carried out using a grid topology that has been modified to reduce the inaccuracies caused by grid spreading often suffered with CFD methods when calculations several body lengths downstream become necessary. Comparisons of CFD results and experimental wind tunnel signatures are shown. Ground signatures are predicted by extrapolating the pressures predicted by the Euler code with an extrapolation method based on the Whitham theory.

  16. Shuttle sonic boom - Technology and predictions. [environmental impact

    NASA Technical Reports Server (NTRS)

    Holloway, P. F.; Wilhold, G. A.; Jones, J. H.; Garcia, F., Jr.; Hicks, R. M.

    1973-01-01

    Because the shuttle differs significantly in both geometric and operational characteristics from conventional supersonic aircraft, estimation of sonic boom characteristics required a new technology base. The prediction procedures thus developed are reviewed. Flight measurements obtained for both the ascent and entry phases of the Apollo 15 and 16 and for the ascent phase only of the Apollo 17 missions are presented which verify the techniques established for application to shuttle. Results of extensive analysis of the sonic boom overpressure characteristics completed to date are presented which indicate that this factor of the shuttle's environmental impact is predictable, localized, of short duration and acceptable. Efforts are continuing to define the shuttle sonic boom characteristics to a fine level of detail based on the final system design.

  17. The sonic boom of an oblique flying wing

    NASA Technical Reports Server (NTRS)

    Kroo, Ilan; Van Der Velden, Alex

    1990-01-01

    An analysis of sonic boom characteristics of an oblique flying wing is presented. The wing, represented by a slewed lift and area-distribution as well as a panel geometry, promises a reduction of sonic boom signature. For every azimuth angle these distributions are represented by an equivalent body. The near-field pressure signature is determined by using the Whitham F-function with a correction to account for nonlinear wave propagation. The geometric asymmetry leads to an asymmetrical sonic boom beneath the flight track with bow shocks between 1.0 and 1.5 PSF. Due to favorable volume-lift interference the aft shock has only half the amplitude of the bow shock. A fast numerical method is described to calculate the perceived loudness.

  18. Review and status of sonic boom penetration into the ocean.

    PubMed

    Sparrow, Victor W

    2002-01-01

    Since the 1970 Sonic Boom Symposium, held at the ASA's 80th meeting in Houston, TX, substantial progress has been made in understanding the penetration of sonic booms into the ocean. The state of the art at that time was documented by J. C. Cook, T. Goforth, and R. K. Cook [J. Acoust. Soc. Am. 51, 729-741 (1972)]. Since then, additional experiments have been performed which corroborate Cook's and Sawyers' theory for sonic boom penetration into a flat ocean surface. In addition, computational simulations have validated that theory and extended the work to include arbitrarily shaped waveforms penetrating flat ocean surfaces. Further numerical studies have investigated realistic ocean surfaces including large-scale ocean swell. Research has also been performed on the effects of ocean inhomogeneities due to bubble plumes. This paper provides a brief overview of these developments. PMID:11837959

  19. Sonic-boom-induced building structure responses including damage.

    NASA Technical Reports Server (NTRS)

    Clarkson, B. L.; Mayes, W. H.

    1972-01-01

    Concepts of sonic-boom pressure loading of building structures and the associated responses are reviewed, and results of pertinent theoretical and experimental research programs are summarized. The significance of sonic-boom load time histories, including waveshape effects, are illustrated with the aid of simple structural elements such as beams and plates. Also included are discussions of the significance of such other phenomena as three-dimensional loading effects, air cavity coupling, multimodal responses, and structural nonlinearities. Measured deflection, acceleration, and strain data from laboratory models and full-scale building tests are summarized, and these data are compared, where possible, with predicted values. Damage complaint and claim experience due both to controlled and uncontrolled supersonic flights over communities are summarized with particular reference to residential, commercial, and historic buildings. Sonic-boom-induced building responses are compared with those from other impulsive loadings due to natural and cultural events and from laboratory simulation tests.

  20. A practical low-boom overpressure signature based on minimum sonic boom theory

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.; Haglund, George T.

    1992-01-01

    A brief resume of sonic boom minimization methods is given to provide a background for a new, empirical modification of the Seebass and George minimum-nose-shock sonic boom F-function and signature. The new 'hybrid' F-function has all the inherent flexibility of application found with the Darden-modified Seebass and George F-function. In addition, it has enhanced this flexibility and applicability with neglegible increase in nose and/or tail shock strength. A description of this 'hybrid' F-function and signature is provided, and the benefits of using them to design high-performance, low-boom aircraft are discussed.

  1. Specialized CFD Grid Generation Methods for Near-Field Sonic Boom Prediction

    NASA Technical Reports Server (NTRS)

    Park, Michael A.; Campbell, Richard L.; Elmiligui, Alaa; Cliff, Susan E.; Nayani, Sudheer N.

    2014-01-01

    Ongoing interest in analysis and design of low sonic boom supersonic transports re- quires accurate and ecient Computational Fluid Dynamics (CFD) tools. Specialized grid generation techniques are employed to predict near- eld acoustic signatures of these con- gurations. A fundamental examination of grid properties is performed including grid alignment with ow characteristics and element type. The issues a ecting the robustness of cylindrical surface extrusion are illustrated. This study will compare three methods in the extrusion family of grid generation methods that produce grids aligned with the freestream Mach angle. These methods are applied to con gurations from the First AIAA Sonic Boom Prediction Workshop.

  2. Initial Results from the Variable Intensity Sonic Boom Propagation Database

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.; Cliatt, Larry J., II; Bunce, Thomas J.; Gabrielson, Thomas B.; Sparrow, Victor W.; Locey, Lance L.

    2008-01-01

    An extensive sonic boom propagation database with low- to normal-intensity booms (overpressures of 0.08 lbf/sq ft to 2.20 lbf/sq ft) was collected for propagation code validation, and initial results and flight research techniques are presented. Several arrays of microphones were used, including a 10 m tall tower to measure shock wave directionality and the effect of height above ground on acoustic level. A sailplane was employed to measure sonic booms above and within the atmospheric turbulent boundary layer, and the sailplane was positioned to intercept the shock waves between the supersonic airplane and the ground sensors. Sailplane and ground-level sonic boom recordings were used to generate atmospheric turbulence filter functions showing excellent agreement with ground measurements. The sonic boom prediction software PCBoom4 was employed as a preflight planning tool using preflight weather data. The measured data of shock wave directionality, arrival time, and overpressure gave excellent agreement with the PCBoom4-calculated results using the measured aircraft and atmospheric data as inputs. C-weighted acoustic levels generally decreased with increasing height above the ground. A-weighted and perceived levels usually were at a minimum for a height where the elevated microphone pressure rise time history was the straightest, which is a result of incident and ground-reflected shock waves interacting.

  3. Experimental Sonic Boom Measurements on a Mach 1.6 Cruise Low-Boom Configuration

    NASA Technical Reports Server (NTRS)

    Wilcox, Floyd J., Jr.; Elmiligui, Alaa, A.; Wayman, Thomas R.; Waithe, Kenrick A.; Howe, Donald C.; Bangert, Linda S.

    2012-01-01

    A wind tunnel test has been conducted by Gulfstream Aerospace Corporation (GAC) to measure the sonic boom pressure signature of a low boom Mach 1.6 cruise business jet in the Langley Unitary Plan Wind Tunnel at Mach numbers 1.60 and 1.80. Through a cooperative agreement between GAC and the National Aeronautics and Space Administration (NASA), GAC provided NASA access to some of the experimental data and NASA is publishing these data for the sonic boom research community. On-track and off-track near field sonic boom pressure signatures were acquired at three separation distances (0.5, 1.2, and 1.7 reference body lengths) and three angles of attack (-0.26deg, 0.26deg, and 0.68deg). The model was blade mounted to minimize the sting effects on the sonic boom signatures. Although no extensive data analysis is provided, selected data are plotted to illustrate salient features of the data. All of the experimental sonic boom pressure data are tabulated. Schlieren images of the configuration are also included.

  4. Prediction of Airplane Sonic-Boom Pressure Fields

    NASA Technical Reports Server (NTRS)

    Carlson, Harry W.; McLean, F. Edward; Middleton, Wilbur D.

    1965-01-01

    This paper presents a discussion of the sensitivity of supersonic-transport design and operation to sonic-boom considerations and shows the necessity for a study of these problems early in the development program. Methods of predicting pressure signatures are outlined and examples of the correlation of these estimates with wind-tunnel and flight measurements are shown. Estimates of sonic-boom characteristics for a representative supersonic transport show that in the critical transonic acceleration portion of the flight, overpressures somewhat lower than estimated by the use of far-field assumptions may be expected. Promising design possibilities for the achievement of further overpressure reductions are explored.

  5. A methodology for designing aircraft to low sonic boom constraints

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.; Needleman, Kathy E.

    1991-01-01

    A method for designing conceptual supersonic cruise aircraft to meet low sonic boom requirements is outlined and described. The aircraft design is guided through a systematic evolution from initial three view drawing to a final numerical model description, while the designer using the method controls the integration of low sonic boom, high supersonic aerodynamic efficiency, adequate low speed handling, and reasonable structure and materials technologies. Some experience in preliminary aircraft design and in the use of various analytical and numerical codes is required for integrating the volume and lift requirements throughout the design process.

  6. Influence of vehicle configuration and flight profile on X-30 sonic booms

    NASA Astrophysics Data System (ADS)

    Maglieri, Domenic J.; Sothcott, Victor E.; Hicks, John

    1990-10-01

    The role of vehicle configuration and the flight profile on sonic booms produced by the experimental NASP X-30 is investigated. Sonic boom signatures, overpressure levels, and footprints for X-30 are presented and compared with sonic boom measurements for F-104, SR-71, Concorde, XB-70, and STS Orbiter. Results show that the sonic boom signatures for X-30 fall within those of previous high-speed planes.

  7. Origins and Overview of the Shaped Sonic Boom Demonstration Program

    NASA Technical Reports Server (NTRS)

    Pawlowski, Joseph W.; Graham, David H.; Boccadoro, Charles H.; Coen, Peter G.; Maglieri, Domenic J.

    2005-01-01

    The goal of the DARPA Shaped Sonic Boom Demonstration (SSBD) Program was to demonstrate for the first time in flight that sonic booms can be substantially reduced by incorporating specialized aircraft shaping techniques. Although mitigation of the sonic boom via specialized shaping techniques was theorized decades ago, until now, this theory had never been tested with a flight vehicle subjected to actual flight conditions in a real atmosphere. The demonstrative success, which occurred on 27 August 2003 with repeat flights in the supersonic corridor at Edwards Air Force Base, is a critical milestone in the development of next generation supersonic aircraft that could one day fly unrestricted over land and help usher in a new era of time-critical air transport. Pressure measurements obtained on the ground and in the air confirmed that the specific modifications made to a Northrop Grumman F-5E aircraft not only changed the shape of the shock wave signature emanating from the aircraft, but also produced a flat-top signature whose shape persisted, as predicted, as the pressure waves propagated through the atmosphere to the ground. This accomplishment represents a major advance towards reducing the startling and potentially damaging noise of a sonic boom. This paper describes the evolution of the SSBD program, including the rationale for test article selection, and provides an overview of the history making accomplishments achieved during the SSBD effort, as well as, the follow-on NASA Shaped Sonic Boom Experiment (SSBE) Program, whose goal was to further evaluate the characteristics and robustness of shaped boom signatures.

  8. Some Effects of Wing Planform on Sonic Boom

    NASA Technical Reports Server (NTRS)

    Hunton, L. W.; Hicks, R. M.; Mendoza, J. P.

    1973-01-01

    A wind-tunnel investigation was conducted to determine the effect of wing planform on sonic boom at Mach numbers of 1.7, 2.0, and 2.7. The results of the investigation show that the wing leading-edge sweep is one of the primary planform variables affecting the overpressure characteristics.

  9. Environmental Pollution: Noise Pollution - Sonic Boom. Volume I.

    ERIC Educational Resources Information Center

    Defense Documentation Center, Alexandria, VA.

    The unclassified, annotated bibliography is Volume I of a two-volume set on Noise Pollution - Sonic Boom in a series of scheduled bibliographies on Environmental Pollution. Volume II is Confidential. Corporate author-monitoring agency, subject, title, contract, and report number indexes are included. (Author/JR)

  10. Sonic Boom Assessment for the Crew Exploration Vehicle

    NASA Technical Reports Server (NTRS)

    Herron, Marissa

    2007-01-01

    The Constellation Environmental Impact Statement (Cx EIS) requires that an assessment be performed on the environmental impact of sonic booms during the reentry of the Crew Exploration Vehicle (CEV). This included an analysis of current planned vehicle trajectories for the Crew Module (CM) and the Service Module (SM) debris and the determination of the potential impact to the overflown environment.

  11. Sonic boom loudness study and airplane configuration development

    NASA Technical Reports Server (NTRS)

    Brown, Jessica G.; Haglund, George T.

    1988-01-01

    Sonic boom wave form parameters as related to loudness were investigated analytically. The parameters studied include rise time, duration, maximum overpressure and initial overpressure. The design criteria of a 72 dBA for corridors and 65 dBA for unconstrained flight were chosen based on a review of human response testing. The 72 dBA criterion suggests that 1.0 psf shock waves may be acceptable. On that basis, acceptable low sonic boom wave forms were explored with respect to cruise conditions, aerodynamic lifting length requirements and configuration design at M 1.5 and M 2.4. An M 2.4 baseline arrow wing configuration was studied as a possible vehicle for M 1.5 cruise overland. Modifications made to approach the low boom wave form included a slightly longer forebody, staggered nacelles, a lifting arrow wing horizontal tail, and carefully tailored lift and volume elements. The same wave form criteria applied for M 2.4 cruise results in a low boom configuration that has significant weight, length and balance penalties. Further detailed design work is required to reach the target wave form and resultant loudness level for overland cruise at M 1.5. These results so far suggest that a properly designed M 2.4 overwater configuration may be capable of M 1.5 overland operation with sonic boom noise characteristcs that meet the criterion.

  12. USAF single-event sonic boom prediction model: PCBoom3

    NASA Technical Reports Server (NTRS)

    Plotkin, Kenneth J.; Downing, Micah; Page, Juliet A.

    1994-01-01

    The Air Force has developed PCBoom3, a general-purpose, single-event sonic boom prediction model. The model operates on an IBM PC or compatible, under DOS or Windows. It is accessed via an integrated environment which controls building of input cases, running boom calculations, displaying contours and signatures, and managing all associated data. The primary boom calculation is via a variation of FOBOOM, the focus-boom extension of Thomas's program. Aircraft input is either via a user-provided F-function, or simple N-wave F-functions tabulated for about 20 current aircraft. A fast boom calculation, based on Plotkin's SBORT algorithms, is included for simple N-wave F-functions in a windless atmosphere and flight altitudes up to 60,000 feet. After a run is complete, the user can access an index identifying significant events (focal zones, beginning of footprint, etc.), then plot boom amplitude contours and signatures or spectra at any point in the footprint. The primary uses of this program are expected to be operational planning and boom incident investigation. However, because of the commonality between FOBOOM and the MDBOOM program currently being used for low boom configuration design, this program is of interest to the HSCT community, especially as supersonic route planning activity increases. The Air Force recently conducted a flight test program to evaluate the focal zone capabilities of PCBoom3. Initial results of that program validate the prediction of focal zone geometry, amplitudes, and waveforms.

  13. Sonic boom prediction for the Langley Mach 2 low-boom configuration

    NASA Technical Reports Server (NTRS)

    Madson, Michael D.

    1992-01-01

    Sonic boom pressure signatures and aerodynamic force data for the Langley Mach 2 low sonic boom configuration were computed using the TranAir full-potential code. A solution-adaptive Cartesian grid scheme is utilized to compute off-body flow field data. Computations were performed with and without nacelles at several angles of attack. Force and moment data were computed to measure nacelle effects on the aerodynamic characteristics and sonic boom footprints of the model. Pressure signatures were computed both on and off ground-track. Near-field pressure signature computations on ground-track were in good agreement with experimental data. Computed off ground-track signatures showed that maximum pressure peaks were located off ground-track and were significantly higher than the signatures on ground-track. Bow shocks from the nacelle inlets increased lift and drag, and also increased the magnitude of the maximum pressure both on and off ground-track.

  14. Numerical model of sonic boom in 3D kinematic turbulence

    NASA Astrophysics Data System (ADS)

    Coulouvrat, François; Luquet, David; Marchiano, Régis

    2015-10-01

    Sonic boom is one of the key issues to be considered in the development of future supersonic or hypersonic civil aircraft concepts. The classical sonic boom, typical for Concorde with an N-wave shape and a ground amplitude of the order of 100 Pa, prevents overland flight. Future concepts target carefully shaped sonic booms with low amplitude weak shocks. However, sonic boom when perceived at the ground level is influenced not only by the aircraft characteristics, but also by atmospheric propagation. In particular, the effect of atmospheric turbulence on sonic boom propagation near the ground is not well characterized. Flight tests performed as early as the 1960s demonstrated that classical sonic booms are sensitive to atmospheric turbulence. However, this sensitivity remains only partially understood. This is related to the fact that i) turbulence is a random process that requires a statistical approach, ii) standard methods used to predict sonic booms, mainly geometrical acoustics based on ray tracing, are inadequate within the turbulent planetary boundary layer. Moreover, the ray theory fails to predict the acoustical field in many areas of interest, such as caustics or shadow zones. These zones are of major interest for sonic boom acceptability (highest levels, lateral extent of zone of impact). These limitations outline the need for a numerical approach that is sufficiently efficient to perform a large number of realizations for a statistical approach, but that goes beyond the limitations of ray theory. With this in view, a 3D one-way numerical method solving a nonlinear scalar wave equation established for heterogeneous, moving and absorbing atmosphere, is used to assess the effects of a 3D kinematic turbulence on sonic boom in various configurations. First, a plane N-wave is propagated in the free field through random realizations of kinematic fluctuations. Then the case of a more realistic Atmospheric Boundary Layer (ABL) is investigated, with a mean

  15. Design and Computational/Experimental Analysis of Low Sonic Boom Configurations

    NASA Technical Reports Server (NTRS)

    Cliff, Susan E.; Baker, Timothy J.; Hicks, Raymond M.

    1999-01-01

    Recent studies have shown that inviscid CFD codes combined with a planar extrapolation method give accurate sonic boom pressure signatures at distances greater than one body length from supersonic configurations if either adapted grids swept at the approximate Mach angle or very dense non-adapted grids are used. The validation of CFD for computing sonic boom pressure signatures provided the confidence needed to undertake the design of new supersonic transport configurations with low sonic boom characteristics. An aircraft synthesis code in combination with CFD and an extrapolation method were used to close the design. The principal configuration of this study is designated LBWT (Low Boom Wing Tail) and has a highly swept cranked arrow wing with conventional tails, and was designed to accommodate either 3 or 4 engines. The complete configuration including nacelles and boundary layer diverters was evaluated using the AIRPLANE code. This computer program solves the Euler equations on an unstructured tetrahedral mesh. Computations and wind tunnel data for the LBWT and two other low boom configurations designed at NASA Ames Research Center are presented. The two additional configurations are included to provide a basis for comparing the performance and sonic boom level of the LBWT with contemporary low boom designs and to give a broader experiment/CFD correlation study. The computational pressure signatures for the three configurations are contrasted with on-ground-track near-field experimental data from the NASA Ames 9x7 Foot Supersonic Wind Tunnel. Computed pressure signatures for the LBWT are also compared with experiment at approximately 15 degrees off ground track.

  16. Sonic boom predictions using a modified Euler code

    NASA Astrophysics Data System (ADS)

    Siclari, Michael J.

    1992-04-01

    The environmental impact of a next generation fleet of high-speed civil transports (HSCT) is of great concern in the evaluation of the commercial development of such a transport. One of the potential environmental impacts of a high speed civilian transport is the sonic boom generated by the aircraft and its effects on the population, wildlife, and structures in the vicinity of its flight path. If an HSCT aircraft is restricted from flying overland routes due to excessive booms, the commercial feasibility of such a venture may be questionable. NASA has taken the lead in evaluating and resolving the issues surrounding the development of a high speed civilian transport through its High-Speed Research Program (HSRP). The present paper discusses the usage of a Computational Fluid Dynamics (CFD) nonlinear code in predicting the pressure signature and ultimately the sonic boom generated by a high speed civilian transport. NASA had designed, built, and wind tunnel tested two low boom configurations for flight at Mach 2 and Mach 3. Experimental data was taken at several distances from these models up to a body length from the axis of the aircraft. The near field experimental data serves as a test bed for computational fluid dynamic codes in evaluating their accuracy and reliability for predicting the behavior of future HSCT designs. Sonic boom prediction methodology exists which is based on modified linear theory. These methods can be used reliably if near field signatures are available at distances from the aircraft where nonlinear and three dimensional effects have diminished in importance. Up to the present time, the only reliable method to obtain this data was via the wind tunnel with costly model construction and testing. It is the intent of the present paper to apply a modified three dimensional Euler code to predict the near field signatures of the two low boom configurations recently tested by NASA.

  17. Sonic boom predictions using a modified Euler code

    NASA Technical Reports Server (NTRS)

    Siclari, Michael J.

    1992-01-01

    The environmental impact of a next generation fleet of high-speed civil transports (HSCT) is of great concern in the evaluation of the commercial development of such a transport. One of the potential environmental impacts of a high speed civilian transport is the sonic boom generated by the aircraft and its effects on the population, wildlife, and structures in the vicinity of its flight path. If an HSCT aircraft is restricted from flying overland routes due to excessive booms, the commercial feasibility of such a venture may be questionable. NASA has taken the lead in evaluating and resolving the issues surrounding the development of a high speed civilian transport through its High-Speed Research Program (HSRP). The present paper discusses the usage of a Computational Fluid Dynamics (CFD) nonlinear code in predicting the pressure signature and ultimately the sonic boom generated by a high speed civilian transport. NASA had designed, built, and wind tunnel tested two low boom configurations for flight at Mach 2 and Mach 3. Experimental data was taken at several distances from these models up to a body length from the axis of the aircraft. The near field experimental data serves as a test bed for computational fluid dynamic codes in evaluating their accuracy and reliability for predicting the behavior of future HSCT designs. Sonic boom prediction methodology exists which is based on modified linear theory. These methods can be used reliably if near field signatures are available at distances from the aircraft where nonlinear and three dimensional effects have diminished in importance. Up to the present time, the only reliable method to obtain this data was via the wind tunnel with costly model construction and testing. It is the intent of the present paper to apply a modified three dimensional Euler code to predict the near field signatures of the two low boom configurations recently tested by NASA.

  18. Sonic boom measurements from accelerating supersonic tracked sleds

    NASA Technical Reports Server (NTRS)

    Reed, J. W.

    1974-01-01

    Supersonic sled tests on the Sandia 1524-m (5000-ft) track generate sonic booms of sufficient intensity to allow some airblast measurements at distance scales not obtained from wind tunnel or flight tests. During acceleration, an emitted curved boom wave propagates to a caustic, or focus. Detailed measurements around these caustics may help to clarify the overpressure magnification which can occur from real aircraft operations. Six fixed pressure gages have been operated to document the general noise field, and a mobile array of twelve gages.

  19. LAVA Simulations for the AIAA Sonic Boom Prediction Workshop

    NASA Technical Reports Server (NTRS)

    Housman, Jeffrey A.; Sozer, Emre; Moini-Yekta , Shayan; Kiris, Cetin C.

    2014-01-01

    Computational simulations using the Launch Ascent and Vehicle Aerodynamics (LAVA) framework are presented for the First AIAA Sonic Boom Prediction Workshop test cases. The framework is utilized with both structured overset and unstructured meshing approaches. The three workshop test cases include an axisymmetric body, a Delta Wing-Body model, and a complete low-boom supersonic transport concept. Solution sensitivity to mesh type and sizing, and several numerical convective flux discretization choices are presented and discussed. Favorable comparison between the computational simulations and experimental data of nearand mid-field pressure signatures were obtained.

  20. Numerical Simulation for sonic boom propagation through an Inhomogeneous atmosphere with winds

    NASA Astrophysics Data System (ADS)

    Yamamoto, Masafumi; Hashimoto, Atsushi; Takahashi, Takashi; Kamakura, Tomoo; Sakai, Takeharu

    2012-09-01

    Noise annoyance due to sonic boom is one of the serious problems for development of next-generation supersonic transport. To decrease this sonic boom noise, the design and analysis techniques are developed at Japan Aerospace eXploration Agency (JAXA). To predict the sonic boom on the ground accurately, we have developed a numerical code (Xnoise) using the augmented Burgers equation combined with the ray tracing. In this method, effects of nonlinearity, geometrical spreading, inhomogeneity of atmosphere, thermoviscous attenuation, molecular vibration relaxation and winds are taken into account. This method gives an estimation of the rise times of ground signatures without resorting to the weak shock theory and area balancing techniques. The nonlinear term is evaluated by the finite difference scheme in this method. In ray-path calculation, an explicit updating methodology is adopted. The augmented Burgers equation is numerically solved by using the operator split method entirely in the time domain. As for the effects of nonlinearity, geometrical spreading, and atmospheric inhomogeneity, the result obtained with the augmented Burgers equation agrees well with that obtained with the waveform parameter method (Thomas' method). For the effects of absorption and dispersion, the calculation based on the augmented Burgers equation is verified by comparing with a detailed one-dimensional CFD analysis. Moreover, we show calculations which account the effect of winds on the propagation of a sonic boom. The validation of model is a future work.

  1. Sonic-boom ground-pressure measurements from Apollo 15

    NASA Technical Reports Server (NTRS)

    Hilton, D. A.; Henderson, H. R.; Mckinney, R.

    1972-01-01

    Sonic boom pressure signatures recorded during the launch and reentry phases of the Apollo 15 mission are presented. The measurements were obtained along the vehicle ground track at 87 km and 970 km downrange from the launch site during ascent; and at 500 km, 55.6 km, and 12.9 km from the splashdown point during reentry. Tracings of the measured signatures are included along with values of the overpressure, impulse, time duration, and rise times. Also included are brief descriptions of the launch and recovery test areas in which the measurements were obtained, the sonic boom instrumentation deployment, flight profiles and operating conditions for the launch vehicle and spacecraft, surface weather information at the measuring sites, and high altitude weather information for the general measurement areas.

  2. Instrumentation for measuring aircraft noise and sonic boom

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J. (Inventor)

    1976-01-01

    Improved instrumentation suitable for measuring aircraft noise and sonic booms is described. An electric current proportional to the sound pressure level at a condenser microphone is produced and transmitted over a cable and amplified by a zero drive amplifier. The converter consists of a local oscillator, a dual-gate field-effect transistor mixer, and a voltage regulator/impedance translator. The improvements include automatic tuning compensation against changes in static microphone capacitance and means for providing a remote electrical calibration capability.

  3. Implications for high speed research: The relationship between sonic boom signature distortion and atmospheric turbulence

    NASA Technical Reports Server (NTRS)

    Sparrow, Victor W.; Gionfriddo, Thomas A.

    1994-01-01

    In this study there were two primary tasks. The first was to develop an algorithm for quantifying the distortion in a sonic boom. Such an algorithm should be somewhat automatic, with minimal human intervention. Once the algorithm was developed, it was used to test the hypothesis that the cause of a sonic boom distortion was due to atmospheric turbulence. This hypothesis testing was the second task. Using readily available sonic boom data, we statistically tested whether there was a correlation between the sonic boom distortion and the distance a boom traveled through atmospheric turbulence.

  4. Relaxation and turbulence effects on sonic boom signatures

    NASA Technical Reports Server (NTRS)

    Pierce, Allan D.; Sparrow, Victor W.

    1992-01-01

    The rudimentary theory of sonic booms predicts that the pressure signatures received at the ground begin with an abrupt shock, such that the overpressure is nearly abrupt. This discontinuity actually has some structure, and a finite time is required for the waveform to reach its peak value. This portion of the waveform is here termed the rise phase, and it is with this portion that this presentation is primarily concerned. Any time characterizing the duration of the rise phase is loosely called the 'rise time.' Various definitions are used in the literature for this rise time. In the present discussion the rise time can be taken as the time for the waveform to rise from 10 percent of its peak value to 90 percent of its peak value. The available data on sonic booms that appears in the open literature suggests that typical values of shock over-pressure lie in the range of 30 Pa to 200 Pa, typical values of shock duration lie in the range of 150 ms to 250 ms, and typical values of the rise time lie in the range of 1 ms to 5 ms. The understanding of the rise phase of sonic booms is important because the perceived loudness of a shock depends primarily on the structure of the rise phase. A longer rise time typically implies a less loud shock. A primary question is just what physical mechanisms are most important for the determination of the detailed structure of the rise phase.

  5. Influence of chair vibrations on indoor sonic boom annoyance

    NASA Astrophysics Data System (ADS)

    Rathsam, Jonathan; Klos, Jacob; Loubeau, Alexandra

    2015-10-01

    One goal of NASA's Commercial Supersonic Technology Project is to identify candidate noise metrics suitable for regulating quiet sonic boom aircraft. A suitable metric must consider the short duration and pronounced low frequency content of sonic booms. For indoor listeners, rattle and creaking sounds and floor and chair vibrations may also be important. The current study examined the effect of such vibrations on the annoyance of test subjects seated indoors. The study involved two chairs exposed to nearly identical acoustic levels: one placed directly on the floor, and the other isolated from floor vibrations by pneumatic elastomeric mounts. All subjects experienced both chairs, sitting in one chair for the first half of the experiment and the other chair for the remaining half. Each half of the experiment consisted of 80 impulsive noises played at the exterior of the sonic boom simulator. When all annoyance ratings were analyzed together there appeared to be no difference in mean annoyance with isolation condition. When the apparent effect of transfer bias was removed, a subtle but measurable effect of vibration on annoyance was identified.

  6. Influence of Chair Vibrations on Indoor Sonic Boom Annoyance

    NASA Technical Reports Server (NTRS)

    Rathsam, Jonathan; Klos, Jacob; Loubeau, Alexandra

    2015-01-01

    One goal of NASA’s Commercial Supersonic Technology Project is to identify candidate noise metrics suitable for regulating quiet sonic boom aircraft. A suitable metric must consider the short duration and pronounced low frequency content of sonic booms. For indoor listeners, rattle and creaking sounds and floor and chair vibrations may also be important. The current study examined the effect of such vibrations on the annoyance of test subjects seated indoors. The study involved two chairs exposed to nearly identical acoustic levels: one placed directly on the floor, and the other isolated from floor vibrations by pneumatic elastomeric mounts. All subjects experienced both chairs, sitting in one chair for the first half of the experiment and the other chair for the remaining half. Each half of the experiment consisted of 80 impulsive noises played at the exterior of the sonic boom simulator. When all annoyance ratings were analyzed together there appeared to be no difference in mean annoyance with isolation condition. When the apparent effect of transfer bias was removed, a subtle but measurable effect of vibration on annoyance was identified.

  7. Effect of sonic boom asymmetry on subjective loudness

    NASA Technical Reports Server (NTRS)

    Leatherwood, Jack D.; Sullivan, Brenda M.

    1992-01-01

    The NASA Langley Research Center's sonic boom apparatus was used in an experimental study to quantify subjective loudness response to a wide range of asymmetrical N-wave sonic boom signatures. Results were used to assess the relative performance of several metrics as loudness estimators for asymmetrical signatures and to quantify in detail the effects on subjective loudness of varying both the degree and direction of signature loudness asymmetry. Findings of the study indicated that Perceived Level (Steven's Mark 7) and A-weighted sound exposure level were the best metrics for quantifying asymmetrical boom loudness. Asymmetrical signatures were generally rated as being less loud than symmetrical signatures of equivalent Perceived Level. The magnitude of the loudness reductions increased as the degree of boom asymmetry increased, and depended upon the direction of asymmetry. These loudness reductions were not accounted for by any of the metrics. Corrections were determined for use in adjusting calculated Perceived Level values to account for these reductions. It was also demonstrated that the subjects generally incorporated the loudness components of the complete signatures when making their subjective judgments.

  8. Evaluation of an Indoor Sonic Boom Subjective Test Facility at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Loubeau, Alexandra; Rathsam, Jonathan; Klos, Jacob

    2011-01-01

    A sonic boom simulator at NASA Langley Research Center has been constructed for research on human response to low-amplitude sonic booms heard indoors. Research in this facility will ultimately lead to development of a psychoacoustic model for single indoor booms. The first subjective test was designed to explore indoor human response to variations in sonic boom rise time and amplitude. Another goal was to identify loudness level variability across listener locations within the facility. Finally, the test also served to evaluate the facility as a laboratory research tool for studying indoor human response to sonic booms. Subjects listened to test sounds and were asked to rate their annoyance relative to a reference boom. Measurements of test signals were conducted for objective analysis and correlation with subjective responses. Results confirm the functionality of the facility and effectiveness of the test methods and indicate that loudness level does not fully describe indoor annoyance to the selected sonic boom signals.

  9. Lateral spread of sonic boom measurements from US Air Force boomfile flight tests

    NASA Technical Reports Server (NTRS)

    Downing, J. Micah

    1992-01-01

    A series of sonic boom flight tests were conducted by the US Air Force at Edwards AFB in 1987 with current supersonic DOD aircraft. These tests involved 43 flights by various aircraft at different Mach number and altitude combinations. The measured peak overpressures to predicted values as a function of lateral distance are compared. Some of the flights are combined into five groups because of the varying profiles and the limited number of sonic booms obtained during this study. The peak overpressures and the lateral distances are normalized with respect to the Carlson method predicted centerline overpressures and lateral cutoff distances, respectively, to facilitate comparisons between sonic boom data from similar flight profiles. It is demonstrated that the data agrees with sonic boom theory and previous studies and adds to the existing sonic boom database by including sonic boom signatures, tracking, and weather data in a digital format.

  10. Comparisons of Methods for Predicting Community Annoyance Due to Sonic Booms

    NASA Technical Reports Server (NTRS)

    Hubbard, Harvey H.; Shepherd, Kevin P.

    1996-01-01

    Two approaches to the prediction of community response to sonic boom exposure are examined and compared. The first approach is based on the wealth of data concerning community response to common transportation noises coupled with results of a sonic boom/aircraft noise comparison study. The second approach is based on limited field studies of community response to sonic booms. Substantial differences between indoor and outdoor listening conditions are observed. Reasonable agreement is observed between predicted community responses and available measured responses.

  11. Unstructured Grids for Sonic Boom Analysis and Design

    NASA Technical Reports Server (NTRS)

    Campbell, Richard L.; Nayani, Sudheer N.

    2015-01-01

    An evaluation of two methods for improving the process for generating unstructured CFD grids for sonic boom analysis and design has been conducted. The process involves two steps: the generation of an inner core grid using a conventional unstructured grid generator such as VGRID, followed by the extrusion of a sheared and stretched collar grid through the outer boundary of the core grid. The first method evaluated, known as COB, automatically creates a cylindrical outer boundary definition for use in VGRID that makes the extrusion process more robust. The second method, BG, generates the collar grid by extrusion in a very efficient manner. Parametric studies have been carried out and new options evaluated for each of these codes with the goal of establishing guidelines for best practices for maintaining boom signature accuracy with as small a grid as possible. In addition, a preliminary investigation examining the use of the CDISC design method for reducing sonic boom utilizing these grids was conducted, with initial results confirming the feasibility of a new remote design approach.

  12. Sonic boom measurement test plan for Space Shuttle STS-5 launch

    NASA Technical Reports Server (NTRS)

    Henderson, H. R.

    1982-01-01

    Sonic booms measurements are obtained at key locations within the focus region and the lateral attenuation rate during ascent is determined in order to assess the validity of existing capability to predict the extent of focus boom area, the number of booms within the various zones (focus and nonfocus regions), the overpressures, and focus factors. The sonic boom focus region, consists of a region on the ground (in the form of an inverted 'horseshoe' pattern) in which higher than nominal overpressures can occur.

  13. Summary of recent NASA studies of human response to sonic booms.

    PubMed

    Leatherwood, Jack D; Sullivan, Brenda M; Shepherd, Kevin P; McCurdy, David A; Brown, Sherilyn A

    2002-01-01

    NASA Langley Research Center has conducted three groups of studies on human response to sonic booms: laboratory, "inhome," and field. The laboratory studies were designed to: (1) quantify loudness and annoyance response to a wide range of shaped sonic boom signatures and (2) assess several noise descriptors as estimators of sonic boom subjective effects. The studies were conducted using a sonic boom simulator capable of generating and playing, with high fidelity, both user-prescribed and recorded boom waveforms to test subjects. Results showed that sonic boom waveform shaping provided substantial reductions in loudness and annoyance and that perceived level was the best estimator of subjective effects. Booms having asymmetrical waveforms were found to be less loud than symmetrical waveforms of equivalent perceived level. Subjective responses to simulated ground-reflected waveforms were fully accounted for by perceived level. The inhome study presented participants with simulated sonic booms played within their normal home environment. The results showed that the equal energy theory of annoyance applied to a variety of multiple sonic boom exposures. The field studies concluded that sonic boom annoyance is greater than that in a conventional aircraft noise environment with the same continuous equivalent noise exposure. PMID:11837964

  14. Sonic Booms on Big Structures (SonicBOBS) Phase I Database; NASA Dryden Sensors

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.; Arnac, Sarah Renee

    2010-01-01

    This DVD contains 13 channels of microphone and up to 22 channels of pressure transducer data collected in September, 2009 around several buildings located at Edwards Air Force Base. These data were recorded by NASA Dryden. Not included are data taken by NASA Langley and Gulfstream. Each day's data is in a separate folder and each pass is in a file beginning with "SonicBOBS_" (for microphone data) or "SonicBOBSBB_" (for BADS and BASS data) followed by the month, day, year as two digits each, followed by the hour, minute, sec after midnight GMT. The filename time given is for the END time of the raw recording file. In the case of the microphone data, this time may be several minutes after the sonic boom, and is according to the PC's uncalibrated clock. The Matlab data files have the actual time as provided by a GPS-based IRIG-B signal recorded concurrently with the data. Microphone data is given for 5 seconds prior to 20 seconds after the sonic boom. BADS and BASS data is given for the full recording, 6 seconds for the BADS and 10 seconds for the BASS. As an example of the naming convention, file "SonicBOBS_091209154618.mat" is from September 12, 2009 at 15:46:18 GMT. Note that data taken on September 12, 2009 prior to 01:00:00 GMT was of the Space Shuttle Discovery (a sonic boom of opportunity), which was on September 11, 2009 in local Pacific Daylight Time.

  15. Research on Subjective Response to Simulated Sonic Booms at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Sullivan, Brenda M.

    2005-01-01

    Over the past 15 years, NASA Langley Research Center has conducted many tests investigating subjective response to simulated sonic booms. Most tests have used the Sonic Boom Booth, an airtight concrete booth fitted with loudspeakers that play synthesized sonic booms pre-processed to compensate for the response of the booth/loudspeaker system. Tests using the Booth have included investigations of shaped booms, booms with simulated ground reflections, recorded booms, outdoor and indoor booms, booms with differing loudness for bow and tail shocks, and comparisons of aircraft flyover recordings with sonic booms. Another study used loudspeakers placed inside people s houses, so that they could experience the booms while in their own homes. This study investigated the reactions of people to different numbers of booms heard within a 24-hour period. The most recent Booth test used predicted boom shapes from candidate low-boom aircraft. At present, a test to compare the Booth with boom simulators constructed by Gulfstream Aerospace Corporation and Lockheed Martin Aeronautics Company is underway. The Lockheed simulator is an airtight booth similar to the Langley booth; the Gulfstream booth uses a traveling wave method to create the booms. Comparison of "realism" as well as loudness and other descriptors is to be studied.

  16. Sonic Boom Mitigation Through Aircraft Design and Adjoint Methodology

    NASA Technical Reports Server (NTRS)

    Rallabhandi, Siriam K.; Diskin, Boris; Nielsen, Eric J.

    2012-01-01

    This paper presents a novel approach to design of the supersonic aircraft outer mold line (OML) by optimizing the A-weighted loudness of sonic boom signature predicted on the ground. The optimization process uses the sensitivity information obtained by coupling the discrete adjoint formulations for the augmented Burgers Equation and Computational Fluid Dynamics (CFD) equations. This coupled formulation links the loudness of the ground boom signature to the aircraft geometry thus allowing efficient shape optimization for the purpose of minimizing the impact of loudness. The accuracy of the adjoint-based sensitivities is verified against sensitivities obtained using an independent complex-variable approach. The adjoint based optimization methodology is applied to a configuration previously optimized using alternative state of the art optimization methods and produces additional loudness reduction. The results of the optimizations are reported and discussed.

  17. Research of the sonic-boom problem. [wind tunnel tests to measure sonic boom strength and to develop formulas for numerical analysis of flow conditions

    NASA Technical Reports Server (NTRS)

    Drougge, G.

    1973-01-01

    Wind tunnel tests were conducted to determine the characteristics of sonic booms. A theoretical examination of nonlinear effects in near and far flow fields, as well as sonic boom shock strength, is reported. A study of the Mach lines and bicharacteristics in three dimensional flow was pursued. The direction derivatives if the bicharacteristics were calculated in a general three dimensional flow field. A second order theory for supersonic flow past slender bodies was developed. Formulas relating flow deflections to the Whitham F-function were derived, which permitted determination of the sonic boom strength from wind tunnel measurements fairly close to the body.

  18. Variability of measured sonic boom signatures. Volume 2: Data report

    NASA Technical Reports Server (NTRS)

    Elmer, K. R.; Joshi, M. C.

    1994-01-01

    Sonic boom signatures from two databases, the BOOMFILE and the XB-70, were analyzed in terms of C-weighted sound exposure level (CSEL), A-weighted sound exposure level (ASEL), and Stevens Mark VII perceived level (PLdB), as well as the more traditional peak positive overpressure and rise time. The variability of these parameters due to propagation through atmosphere was analyzed for different aircraft Mach number and altitude groups. The low Mach number/low altitude group had significantly greater variation in rise time, overpressure, and loudness level than the high Mach number/high altitude group. The loudness of measured booms were found to have a variation of up to 25 dB relative to the loudness of boom predicted for a non-turbulent atmosphere. This is due primarily to the steeper ray paths of the high Mach number/high altitude group and the corresponding shorter distances traveled by these rays through the lower atmosphere resulting in reduced refraction effects. The general trend of decreased overpressure and loudness level with increasing lateral distance was also seen. Sonic boom signatures from early morning flights had less variation in rise time and overpressure than afternoon flights because of reduced turbulence. Measures of asymmetry (difference between compression and expansion portion of the signature) showed that the variability in Delta loudness level was greater than the variability in Delta overpressure due to the large influence of turbulence on rise time. Lastly, analysis of data within 50 percent of lateral cutoff showed that the mean value for overpressure and loudness level was independent of time of day but that the frequency with which it occurred was greater in the morning. This is a clear indicator of increased turbulence in the afternoon.

  19. Variability of measured sonic boom signatures. Volume 1: Technical report

    NASA Technical Reports Server (NTRS)

    Elmer, K. R.; Joshi, M. C.

    1994-01-01

    Sonic boom signatures from two databases, the BOOMFILE and the XB-70, were analyzed in terms of C-weighted sound exposure level (CSEL), A-weighted sound exposure level (ASEL), and Stevens Mark VII perceived level (PLdB), as well as the more traditional peak positive overpressure and rise time. The variability of these parameters due to propagation through atmosphere was analyzed for different aircraft Mach number and altitude groups. The low Mach number/low altitude group had significantly greater variation in rise time, overpressure, and loudness level than the high Mach number/high altitude group. The loudness of measured booms were found to have a variation of up to 25 dB relative to the loudness of boom predicted for a non-turbulent atmosphere. This is due primarily to the steeper ray paths of the high Mach number/high altitude group and the corresponding shorter distances traveled by these rays through the lower atmosphere resulting in reduced refraction effects. The general trend of decreased overpressure and loudness level with increasing lateral distance was also seen. Sonic boom signatures from early morning flights had less variation in rise time and overpressure than afternoon flights because of reduced turbulence. Measures of asymmetry (difference between compression and expansion portion of the signature) showed that the variability in Delta loudness level was greater than the variability in Delta overpressure due to the large influence of turbulence on rise time. Lastly, analysis of data within 50 percent of lateral cutoff showed that the mean value for overpressure and loudness level was independent of time of day but that the frequency with which it occurred was greater in the morning. This is a clear indicator of increased turbulence in the afternoon.

  20. The development of a sonic boom simulator with detonable gases

    NASA Technical Reports Server (NTRS)

    Strugielski, R. T.; Fugelso, L. E.; Holmes, L. B.; Byrne, W. J.

    1971-01-01

    A sonic boom pressure profile was simulated in the far-field by detonation of a methane-oxygen mixture contained in a slender, shaped Mylar envelope. Ideal N-waves were synthesized with peak overpressures from two to five psf and durations of 30 to 75 milliseconds. The detonation of the gas mixture was initiated by a single Primacord strand running the length of balloon. The N-wave producing balloon was synthesized as a composite structure, utilizing experimental pressure profiles obtained from the detonations of slender, axisymmetric balloons with elementary, non-cylindrical shapes.

  1. CFD Simulations Of Sonic Booms In Near And Mid Fields

    NASA Technical Reports Server (NTRS)

    Cheung, Samson H.; Edwards, Thomas A.; Lawrence, Scott L.

    1992-01-01

    Report discusses computational fluid dynamics (CFD) to simulate generation and propagation of sonic booms in near- and mid-field regions of supersonic flows about simplified bodies representative of advanced airplanes. Parabolized Navier-Stokes equations integrated by implicit, approximate-factorization, finite-volume algorithm in which crossflow inviscid fluxes evaluated by Roe's flux-difference-splitting scheme. Near-field solutions obtained by applying algorithm to flows immediately surrounding bodies. Solutions transferred to computer codes based on Whitham"s F-function theory for extrapolation to far-field.

  2. Nacelle and forebody considerations in design for reduced sonic boom

    NASA Technical Reports Server (NTRS)

    Haglund, George T.

    1992-01-01

    Several aspects of designing for reduced sonic boom were investigated to assess the adequacy of the conventional modified linear theory. For a simple test case of a nacelle with a small forecowl angle (2 degrees) mounted below a flat plate, the linear theory compared favorably for a case with simulated nacelle lift and for a computational fluid dynamics (CFD) analysis. In a second study, several methods of analyzing the area distribution due to volume were examined. And finally, in a preliminary study, the effect of forebody shape on the rise time of the bow shock was investigated, indicating a significant increase (several msec) can be obtained by proper forebody shaping.

  3. The 1995 NASA High-Speed Research Program Sonic Boom Workshop. Volume 1

    NASA Technical Reports Server (NTRS)

    Baize, Daniel G. (Editor)

    1996-01-01

    The High-Speed Research Program and NASA Langley Research Center sponsored the NASA High-Speed Research Program Sonic Boom Workshop on September 12-13, 1995. The workshop was designed to bring together NASAs scientists and engineers and their counterparts in industry, other Government agencies, and academia working together in the sonic boom element of NASAs High-Speed Research Program. Specific objectives of this workshop were to (1) report the progress and status of research in sonic boom propagation, acceptability, and design; (2) promote and disseminate this technology within the appropriate technical communities; (3) help promote synergy among the scientists working in the Program; and (4) identify technology pacing the development of viable reduced-boom High-Speed Civil Transport concepts. The Workshop included these sessions: Session 1 - Sonic Boom Propagation (Theoretical); Session 2 - Sonic Boom Propagation (Experimental); and Session 3 - Acceptability Studies - Human and Animal.

  4. Waveforms and Sonic Boom Perception and Response (WSPR): Low-Boom Community Response Program Pilot Test Design, Execution, and Analysis

    NASA Technical Reports Server (NTRS)

    Page, Juliet A.; Hodgdon, Kathleen K.; Krecker, Peg; Cowart, Robbie; Hobbs, Chris; Wilmer, Clif; Koening, Carrie; Holmes, Theresa; Gaugler, Trent; Shumway, Durland L.; Rosenberger, James L.; Philips, Daisy

    2014-01-01

    The Waveforms and Sonic boom Perception and Response (WSPR) Program was designed to test and demonstrate the applicability and effectiveness of techniques to gather data relating human subjective response to multiple low-amplitude sonic booms. It was in essence a practice session for future wider scale testing on naive communities, using a purpose built low-boom demonstrator aircraft. The low-boom community response pilot experiment was conducted in California in November 2011. The WSPR team acquired sufficient data to assess and evaluate the effectiveness of the various physical and psychological data gathering techniques and analysis methods.

  5. Focused and Steady-State Characteristics of Shaped Sonic Boom Signatures: Prediction and Analysis

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Bobbitt, Percy J.; Massey, Steven J.; Plotkin, Kenneth J.; Kandil, Osama A.; Zheng, Xudong

    2011-01-01

    The objective of this study is to examine the effect of flight, at off-design conditions, on the propagated sonic boom pressure signatures of a small "low-boom" supersonic aircraft. The amplification, or focusing, of the low magnitude "shaped" signatures produced by maneuvers such as the accelerations from transonic to supersonic speeds, climbs, turns, pull-up and pushovers is the concern. To analyze these effects, new and/or improved theoretical tools have been developed, in addition to the use of existing methodology. Several shaped signatures are considered in the application of these tools to the study of selected maneuvers and off-design conditions. The results of these applications are reported in this paper as well as the details of the new analytical tools. Finally, the magnitude of the focused boom problem for "low boom" supersonic aircraft designs has been more accurately quantified and potential "mitigations" suggested. In general, "shaped boom" signatures, designed for cruise flight, such as asymmetric and symmetric flat-top and initial-shock ramp waveforms retain their basic shape during transition flight. Complex and asymmetric and symmetric initial shock ramp waveforms provide lower magnitude focus boom levels than N-waves or asymmetric and symmetric flat-top signatures.

  6. Experimental and Computational Sonic Boom Assessment of Boeing N+2 Low Boom Models

    NASA Technical Reports Server (NTRS)

    Durston, Donald A.; Elmiligui, Alaa; Cliff, Susan E.; Winski, Courtney S.; Carter, Melissa B.; Walker, Eric L.

    2015-01-01

    Near-field pressure signatures were measured and computational predictions made for several sonic boom models representing Boeing's Quiet Experimental Validation Concept (QEVC) supersonic transport, as well as three axisymmetric calibration models. Boeing developed the QEVC under a NASA Research Announcement (NRA) contract for Experimental Systems Validations for N+2 Supersonic Commercial Transport Aircraft, which was led by the NASA High Speed Project under the Fundamental Aeronautics Program. The concept was designed to address environmental and performance goals given in the NRA, specifically for low sonic boom loudness levels and high cruise efficiency, for an aircraft anticipated to enter service in the 2020 timeframe. Wind tunnel tests were conducted on the aircraft and calibration models during Phases I and II of the NRA contract from 2011 to 2013 in the NASA Ames 9- by 7-Foot and NASA Glenn 8- by 6-Foot Supersonic Wind Tunnels. Sonic boom pressure signatures were acquired primarily at Mach 1.6 and 1.8, and force and moment data were acquired from Mach 0.8 to 1.8. The sonic boom test data were obtained using a 2-in. flat-top pressure rail and a 14-in. round-top tapered "reflection factor 1" (RF1) pressure rail. Both rails capture an entire pressure signature in one data point, and successive signatures at varying positions along or above the rail were used to improve data quality through spatial averaging. The sonic boom data obtained by the rails were validated with high-fidelity numerical simulations of off-body pressures using the CFD codes USM3D, Cart3D, and OVERFLOW. The test results from the RF1 rail showed good agreement between the computational and experimental data when a variety of testing techniques including spatial averaging of a series of pressure signatures were employed, however, reflections off the 2-in. flat-top rail caused distortions in the signatures that did not agree with the CFD predictions. The 9 x 7 and 8 x 6 wind tunnels generally

  7. Effects of sonic booms on breeding gray seals and harbor seals on Sable Island, Canada.

    PubMed

    Perry, Elizabeth A; Boness, Daryl J; Insley, Stephen J

    2002-01-01

    The Concorde produces audible sonic booms as it passes 15 km north of Sable Island, Nova Scotia, where gray and harbor seals occur year round. The purpose of this research was to assess how sonic booms affect these seals. The intensity of the booms was measured and three types of data (beach counts, frequency of behavior, and heart rate) were collected before and after booms during the breeding seasons of the two species. In addition to the data taken during breeding, beach counts were made before and after booms during the gray seal moult. The greatest range in overpressure within a single boom was 2.70 psf during gray seal breeding and 2.07 psf during harbor seal breeding. No significant differences were found in the behavior or beach counts of gray seals following sonic booms, regardless of the season. Beach counts and most behaviors of harbor seals also did not differ significantly following booms, however, harbor seals became more vigilant. The heart rates of four gray seal mothers and three pups showed no clear change as a result of booms, but six male harbor seals showed a nonsignificant tendency toward elevated heart rates during the 15-s interval of the boom. These results suggest sonic booms produced by the Concorde, in level flight at altitude and producing on average a sonic boom of 0.9 psf, do not substantially affect the breeding behavior of gray or harbor seals. PMID:11837965

  8. Effects of sonic booms on breeding gray seals and harbor seals on Sable Island, Canada

    NASA Astrophysics Data System (ADS)

    Perry, Elizabeth A.; Boness, Daryl J.; Insley, Stephen J.

    2002-01-01

    The Concorde produces audible sonic booms as it passes 15 km north of Sable Island, Nova Scotia, where gray and harbor seals occur year round. The purpose of this research was to assess how sonic booms affect these seals. The intensity of the booms was measured and three types of data (beach counts, frequency of behavior, and heart rate) were collected before and after booms during the breeding seasons of the two species. In addition to the data taken during breeding, beach counts were made before and after booms during the gray seal moult. The greatest range in overpressure within a single boom was 2.70 psf during gray seal breeding and 2.07 psf during harbor seal breeding. No significant differences were found in the behavior or beach counts of gray seals following sonic booms, regardless of the season. Beach counts and most behaviors of harbor seals also did not differ significantly following booms, however, harbor seals became more vigilant. The heart rates of four gray seal mothers and three pups showed no clear change as a result of booms, but six male harbor seals showed a nonsignificant tendency toward elevated heart rates during the 15-s interval of the boom. These results suggest sonic booms produced by the Concorde, in level flight at altitude and producing on average a sonic boom of 0.9 psf, do not substantially affect the breeding behavior of gray or harbor seals.

  9. Wind Tunnel Model Design for Sonic Boom Studies of Nozzle Jet with Shock Interactions

    NASA Technical Reports Server (NTRS)

    Cliff, Susan E.; Denison, Marie; Sozer, Emre; Moini-Yekta, Shayan

    2016-01-01

    NASA and Industry are performing vehicle studies of configurations with low sonic boom pressure signatures. The computational analyses of modern configuration designs have matured to the point where there is confidence in the prediction of the pressure signature from the front of the vehicle, but uncertainty in the aft signatures with often greater boundary layer effects and nozzle jet pressures. Wind tunnel testing at significantly lower Reynolds numbers than in flight and without inlet and nozzle jet pressures make it difficult to accurately assess the computational solutions of flight vehicles. A wind tunnel test in the NASA Ames 9- by 7-Foot Supersonic Wind Tunnel from Mach 1.6 to 2.0 will be used to assess the effects of shocks from components passing through nozzle jet plumes on the sonic boom pressure signature and provide datasets for comparison with CFD codes. A large number of high-fidelity numerical simulations of wind tunnel test models with a variety of shock generators that simulate horizontal tails and aft decks have been studied to provide suitable models for sonic boom pressure measurements using a minimally intrusive pressure rail in the wind tunnel. The computational results are presented and the evolution of candidate wind tunnel models is summarized and discussed in this paper.

  10. Underwater measurements and modeling of a sonic boom.

    PubMed

    Desharnais, Francine; Chapman, David M F

    2002-01-01

    During a sea trial on the Scotian Shelf, acoustic signals from a sonic boom were recorded on 11 hydrophones of a vertical array. The array spanned the lower 50 m of the water column above a sand bank at 76 m water depth. The source of the sonic boom was deduced to be a Concorde supersonic airliner traveling at about Mach 2. The waterborne waveform was observed to decay as an evanescent wave below the sea surface, as expected. The calm weather (sea state 1) resulted in low ambient noise and low self-noise at the hydrophones, and good signal-to-noise ratio on the upper hydrophones; however, the decreased signal amplitude is more difficult to detect towards the lower part of the water column. The period of the observed waveform is of the order 0.23 s, corresponding to a peak frequency of about 3 Hz. The shape of the measured waveform differs noticeably from the theoretical N-shape waveform predicted with Sawyers' theory [J. Acoust. Soc. Am. 44, 523-524 (1968)]. A simple shallow-ocean geoacoustic model suggests that this effect may be caused in part by seismo-acoustic interaction of the infrasonic waves with the elastic sediments that form the seabed. PMID:11858149

  11. Sonic Boom Propagation Codes Validated by Flight Test

    NASA Technical Reports Server (NTRS)

    Poling, Hugh W.

    1996-01-01

    The sonic boom propagation codes reviewed in this study, SHOCKN and ZEPHYRUS, implement current theory on air absorption using different computational concepts. Review of the codes with a realistic atmosphere model confirm the agreement of propagation results reported by others for idealized propagation conditions. ZEPHYRUS offers greater flexibility in propagation conditions and is thus preferred for practical aircraft analysis. The ZEPHYRUS code was used to propagate sonic boom waveforms measured approximately 1000 feet away from an SR-71 aircraft flying at Mach 1.25 to 5000 feet away. These extrapolated signatures were compared to measurements at 5000 feet. Pressure values of the significant shocks (bow, canopy, inlet and tail) in the waveforms are consistent between extrapolation and measurement. Of particular interest is that four (independent) measurements taken under the aircraft centerline converge to the same extrapolated result despite differences in measurement conditions. Agreement between extrapolated and measured signature duration is prevented by measured duration of the 5000 foot signatures either much longer or shorter than would be expected. The duration anomalies may be due to signature probing not sufficiently parallel to the aircraft flight direction.

  12. Progressive wave equations and algorithms for sonic boom propagation

    NASA Astrophysics Data System (ADS)

    Pierce, Allan D.

    Raspet, Bass, and others have carried out a number of studies of sonic boom propagation using algorithms that can be traced back to a 1973 doctoral thesis written by Pestorius at the University of Texas. The algorithm was originally set forth without a formal derivation from a governing set of partial differential equations. Perusal of Pestorius's report and of subsequent reports from the Texas nonlinear accoustics group suggests that such a derivation has not yet appeared in the archival literature. The author and his colleagues, on the other hand, have been working with an explicit set of approximate partial differential equations analogous to Burgers' equation. The present paper traces through the pertinent statements in the Pestorius reports and shows that the derived algorithm, at least in the limit of sufficiently short steps, is equivalent to the numerical solution of a similar (and nearly equivalent) explicit set of partial differential equations. The tying-together of the two approaches is important because it is possible that some of the basic ideas embodied in the Pestorius algorithm may be incorporated in other contexts where more nearly general models of sonic boom propagation through realistic atmospheres are to be solved numerically.

  13. Sonic boom measurement test plan for Space Shuttle STS-2 reentry

    NASA Technical Reports Server (NTRS)

    Henderson, H. R.

    1981-01-01

    Procedures and system specifications associated with the space shuttle STS-2 sonic boom measurement program are described. Specifically included are details such as mobile data acquisition station locations, measurement systems calibration levels, predicted sonic boom overpressure levels, overpressure level assignment for each data acquisition station, data recording times on and off, universal coordinate time, and measurement system descriptions.

  14. Simple atmospheric perturbation models for sonic-boom-signature distortion studies

    NASA Technical Reports Server (NTRS)

    Ehernberger, L. J.; Wurtele, Morton G.; Sharman, Robert D.

    1994-01-01

    Sonic-boom propagation from flight level to ground is influenced by wind and speed-of-sound variations resulting from temperature changes in both the mean atmospheric structure and small-scale perturbations. Meteorological behavior generally produces complex combinations of atmospheric perturbations in the form of turbulence, wind shears, up- and down-drafts and various wave behaviors. Differences between the speed of sound at the ground and at flight level will influence the threshold flight Mach number for which the sonic boom first reaches the ground as well as the width of the resulting sonic-boom carpet. Mean atmospheric temperature and wind structure as a function of altitude vary with location and time of year. These average properties of the atmosphere are well-documented and have been used in many sonic-boom propagation assessments. In contrast, smaller scale atmospheric perturbations are also known to modulate the shape and amplitude of sonic-boom signatures reaching the ground, but specific perturbation models have not been established for evaluating their effects on sonic-boom propagation. The purpose of this paper is to present simple examples of atmospheric vertical temperature gradients, wind shears, and wave motions that can guide preliminary assessments of nonturbulent atmospheric perturbation effects on sonic-boom propagation to the ground. The use of simple discrete atmospheric perturbation structures can facilitate the interpretation of the resulting sonic-boom propagation anomalies as well as intercomparisons among varied flight conditions and propagation models.

  15. Reactions of Residents to Long-Term Sonic Boom Noise Environments

    NASA Technical Reports Server (NTRS)

    Fields, James M.

    1997-01-01

    A combined social survey and noise measurement program has been completed in 14 communities in two regions of the western United States that have been regularly exposed to sonic booms for many years. A total of 1,573 interviews were completed. Three aspects of the sonic booms are most disturbing: being startled, noticing rattles or vibrations, and being concerned about the possibility of damage from the booms. Sonic boom annoyance is greater than that in a conventional aircraft environment with the same continuous equivalent noise exposure. The reactions in the two study regions differ in severity.

  16. A Study in a New Test Facility on Indoor Annoyance Caused by Sonic Booms

    NASA Technical Reports Server (NTRS)

    Rathsam, Jonathan; Loubeau, Alexandra; Klos, Jacob

    2012-01-01

    A sonic-boom simulator at NASA Langley Research Center has been constructed to research the indoor human response to low-amplitude sonic booms. The research goal is the development of a psychoacoustic model for individual sonic booms to be validated by future community studies. The study in this report assessed the suitability of existing noise metrics for predicting indoor human annoyance. The test signals included a wide range of synthesized and recorded sonic-boom waveforms. Results indicated that no noise metric predicts indoor annoyance to sonic-boom sounds better than Perceived Level, PL. During the study it became apparent that structural vibrations induced by the test signals were contributing to annoyance, so the relationship between sound and vibration at levels of equivalent annoyance has been quantified.

  17. Application of magnitude estimation scaling to the assessment of subjective loudness response to simulated sonic booms

    NASA Technical Reports Server (NTRS)

    Mcdaniel, S.; Leatherwood, J. D.; Sullivan, B. M.

    1992-01-01

    A laboratory study was conducted for the following reasons: (1) to investigate the application of magnitude estimation scaling for evaluating the subjective loudness of sonic booms; and (2) to compare the relative merits of magnitude estimation and numerical category scaling for sonic boom loudness evaluation. The study was conducted in the NASA LeRC's sonic boom simulator and used a total of 80 test subjects (48 for magnitude estimation and 32 for numerical category scaling). Results demonstrated that magnitude estimation was a practical and effective method for quantifying subjective loudness of sonic booms. When using magnitude estimation, the subjects made valid and consistent ratio judgments of sonic boom loudness irrespective of the frequency of presentation of the standard stimulus. Presentation of the standard as every fourth stimulus was preferred by the subjects and is recommended as the standard presentation frequency to be used in future tests.

  18. A study of loudness as a metric for sonic boom acceptability

    NASA Technical Reports Server (NTRS)

    Needleman, Kathy E.; Darden, Christine M.; Mack, Robert J.

    1991-01-01

    A parametric study of loudness levels with respect to weight, altitude, and Mach number for sonic boom signatures generated by two Mach 2.0 conceptual configurations is presented and compared with a similar study for nose shock overpressure. This paper discusses the relative importance of the two sonic boom metrics and the implications of the trends shown. Of the two configurations considered in this study, one was designed for optimum aerodynamic performance and the second was designed to produce a constrained overpressure sonic boom signature at cruise flight conditions. Results indicate that reductions in both loudness and overpressure level are possible when the configuration is shaped to produce a low boom signature. Results also prove that the loudness metric is a more reliable measure of the disturbance due to sonic booms than nose shock overpressure, because the overpressure does not include the sometimes significant effects of embedded shocks which are often present in mid-field low boom signatures.

  19. Display Provides Pilots with Real-Time Sonic-Boom Information

    NASA Technical Reports Server (NTRS)

    Haering, Ed; Plotkin, Ken

    2013-01-01

    Supersonic aircraft generate shock waves that move outward and extend to the ground. As a cone of pressurized air spreads across the landscape along the flight path, it creates a continuous sonic boom along the flight track. Several factors can influence sonic booms: weight, size, and shape of the aircraft; its altitude and flight path; and weather and atmospheric conditions. This technology allows pilots to control the impact of sonic booms. A software system displays the location and intensity of shock waves caused by supersonic aircraft. This technology can be integrated into cockpits or flight control rooms to help pilots minimize sonic boom impact in populated areas. The system processes vehicle and flight parameters as well as data regarding current atmospheric conditions. The display provides real-time information regarding sonic boom location and intensity, enabling pilots to make the necessary flight adjustments to control the timing and location of sonic booms. This technology can be used on current-generation supersonic aircraft, which generate loud sonic booms, as well as future- generation, low-boom aircraft, anticipated to be quiet enough for populated areas.

  20. Loudness and annoyance response to simulated outdoor and indoor sonic booms

    NASA Technical Reports Server (NTRS)

    Leatherwood, Jack D.; Sullivan, Brenda M.

    1993-01-01

    The sonic boom simulator of the Langley Research Center was used to quantify subjective loudness and annoyance response to simulated indoor and outdoor sonic boom signatures. The indoor signatures were derived from the outdoor signatures by application of house filters that approximated the noise reduction characteristics of a residential structure. Two indoor listening situations were simulated: one with the windows open and the other with the windows closed. Results were used to assess loudness and annoyance as sonic boom criterion measures and to evaluate several metrics as estimators of loudness and annoyance. The findings indicated that loudness and annoyance were equivalent criterion measures for outdoor booms but not for indoor booms. Annoyance scores for indoor booms were significantly higher than indoor loudness scores. Thus, annoyance was recommended as the criterion measure of choice for general use in assessing sonic boom subjective effects. Perceived level was determined to be the best estimator of annoyance for both indoor and outdoor booms, and of loudness for outdoor booms. It was recommended as the metric of choice for predicting sonic boom subjective effects.

  1. Review of sonic-boom generation theory and prediction methods.

    NASA Technical Reports Server (NTRS)

    Carlson, H. W.; Maglieri, D. J.

    1972-01-01

    The prediction techniques reviedi he present paper permit the calculation of sonic booms produced by rather complex conventional supersonic aircraft designs performing level nonaccelerated flight in a quiet atmosphere. Basic concepts of supersonic flow analysis, for representation of an airplane as a linear distribution of disturbances and for determination of the resultant pressure field complete with shocks, are outlined. Numerical techniques for implementation of the theory are discussed briefly, and examples of the correlation of theory with experimental data from wind tunnel and flight tests are presented. Special attention is given to presentation of a simplified method for rapid 'first-cut' estimation of farfield bow-shock overpressure. Finally, some problems encountered in attempts at applying the prediction techniques for the nearfield at high supersonic Mach numbers are recognized, and the need for further refinement of present techniques or the development of new systems is discussed.

  2. Active control of shocks and sonic boom ground signal

    NASA Astrophysics Data System (ADS)

    Yagiz, Bedri

    The manipulation of a flow field to obtain a desired change is a much heightened subject. Active flow control has been the subject of the major research areas in fluid mechanics for the past two decades. It offers new solutions for mitigation of shock strength, sonic boom alleviation, drag minimization, reducing blade-vortex interaction noise in helicopters, stall control and the performance maximization of existing designs to meet the increasing requirements of the aircraft industries. Despite the wide variety of the potential applications of active flow control, the majority of studies have been performed at subsonic speeds. The active flow control cases were investigated in transonic speed in this study. Although the active flow control provides significant improvements, the sensibility of aerodynamic performance to design parameters makes it a nontrivial and expensive problem, so the designer has to optimize a number of different parameters. For the purpose of gaining understanding of the active flow control concepts, an automated optimization cycle process was generated. Also, the optimization cycle reduces cost and turnaround time. The mass flow coefficient, location, width and angle were chosen as design parameters to maximize the aerodynamic performance of an aircraft. As the main contribution of this study, a detailed parametric study and optimization process were presented. The second step is to appraise the practicability of weakening the shock wave and thereby reducing the wave drag in transonic flight regime using flow control devices such as two dimensional contour bump, individual jet actuator, and also the hybrid control which includes both control devices together, thereby gaining the desired improvements in aerodynamic performance of the air-vehicle. After this study, to improve the aerodynamic performance, the flow control and shape parameters are optimized separately, combined, and in a serial combination. The remarkable part of all these

  3. Instrumentation for measurement of aircraft noise and sonic boom

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J. (Inventor)

    1975-01-01

    A jet aircraft noise and sonic boom measuring device which converts sound pressure into electric current is described. An electric current proportional to the sound pressure level at a condenser microphone is produced and transmitted over a cable, amplified by a zero drive amplifier and recorded on magnetic tape. The converter is comprised of a local oscillator, a dual-gate field-effect transistor (FET) mixer and a voltage regulator/impedance translator. A carrier voltage that is applied to one of the gates of the FET mixer is generated by the local oscillator. The microphone signal is mixed with the carrier to produce an electrical current at the frequency of vibration of the microphone diaphragm by the FET mixer. The voltage of the local oscillator and mixer stages is regulated, the carrier at the output is eliminated, and a low output impedance at the cable terminals is provided by the voltage regulator/impedance translator.

  4. Ballistic range investigation of sonic-boom overpressures in water.

    NASA Technical Reports Server (NTRS)

    Malcolm, G. N.; Intrieri, P. F.

    1972-01-01

    An investigation of sonic-boom overpressures in water has been conducted by gun-launching small cone-cylinder models over water. Flights were conducted at Mach numbers of 2.7 and 5.7, in air, corresponding to Mach numbers of 0.6 and 1.3, respectively, in water. Shadowgraph pictures and underwater pressure measurements indicate that for horizontal flights at Mach numbers below Mach 4.4 in air (i.e., subsonic relative to the speed of sound in water) the resulting underwater disturbance is an acoustic wave whose peak pressure attenuates rapidly with water depth. In contrast, at supersonic Mach numbers, relative to water, the incident shock wave at the surface is transmitted into the water as a propagating shock wave and the peak pressure associated with it does not attenuate with water depth.

  5. Sound, infrasound, and sonic boom absorption by atmospheric clouds.

    PubMed

    Baudoin, Michaël; Coulouvrat, François; Thomas, Jean-Louis

    2011-09-01

    This study quantifies the influence of atmospheric clouds on propagation of sound and infrasound, based on an existing model [Gubaidulin and Nigmatulin, Int. J. Multiphase Flow 26, 207-228 (2000)]. Clouds are considered as a dilute and polydisperse suspension of liquid water droplets within a mixture of dry air and water vapor, both considered as perfect gases. The model is limited to low and medium altitude clouds, with a small ice content. Four physical mechanisms are taken into account: viscoinertial effects, heat transfer, water phase changes (evaporation and condensation), and vapor diffusion. Physical properties of atmospheric clouds (altitude, thickness, water content and droplet size distribution) are collected, along with values of the thermodynamical coefficients. Different types of clouds have been selected. Quantitative evaluation shows that, for low audible and infrasound frequencies, absorption within clouds is several orders of magnitude larger than classical absorption. The importance of phase changes and vapor diffusion is outlined. Finally, numerical simulations for nonlinear propagation of sonic booms indicate that, for thick clouds, attenuation can lead to a very large decay of the boom at the ground level. PMID:21895057

  6. Subjective response of people to simulated sonic booms in their homes

    NASA Astrophysics Data System (ADS)

    McCurdy, David A.; Brown, Sherilyn A.; Hilliard, R. David

    2004-09-01

    In order to determine the effect of the number of sonic boom occurrences on annoyance, a computer-based system was developed for studying the subjective response of people to the occurrence of simulated sonic booms in their homes. The system provided a degree of control over the noise exposure not found in community surveys and a degree of situational realism not available in the laboratory. A system was deployed for eight weeks in each of 33 homes. Each day from 4 to 63 sonic booms were played as the test subject went about his or her normal activities. At the end of the day, the test subjects rated their annoyance to the sonic booms heard during the day. The sonic booms consisted of different combinations of waveforms, levels, and occurrence rates. The experiment confirmed that the increase in annoyance resulting from multiple occurrences can be modeled by the addition of the term ``10 * log(number of occurrences)'' to the sonic boom level. Of several noise metrics considered, perceived level was the best annoyance predictor. Comparisons of the subjective responses to the different sonic boom waveforms found no differences that were not accounted for by the noise metrics.

  7. Laboratory Headphone Studies of Human Response to Low-Amplitude Sonic Booms and Rattle Heard Indoors

    NASA Technical Reports Server (NTRS)

    Loubeau, Alexandra; Sullivan, Brenda M.; Klos, Jacob; Rathsam, Jonathan; Gavin, Joseph R.

    2013-01-01

    Human response to sonic booms heard indoors is affected by the generation of contact-induced rattle noise. The annoyance caused by sonic boom-induced rattle noise was studied in a series of psychoacoustics tests. Stimuli were divided into three categories and presented in three different studies: isolated rattles at the same calculated Perceived Level (PL), sonic booms combined with rattles with the mixed sound at a single PL, and sonic booms combined with rattles with the mixed sound at three different PL. Subjects listened to sounds over headphones and were asked to report their annoyance. Annoyance to different rattles was shown to vary significantly according to rattle object size. In addition, the combination of low-amplitude sonic booms and rattles can be more annoying than the sonic boom alone. Correlations and regression analyses for the combined sonic boom and rattle sounds identified the Moore and Glasberg Stationary Loudness (MGSL) metric as a primary predictor of annoyance for the tested sounds. Multiple linear regression models were developed to describe annoyance to the tested sounds, and simplifications for applicability to a wider range of sounds are presented.

  8. Subjective response of people to simulated sonic booms in their homes.

    PubMed

    McCurdy, David A; Brown, Sherilyn A; Hilliard, R David

    2004-09-01

    In order to determine the effect of the number of sonic boom occurrences on annoyance, a computer-based system was developed for studying the subjective response of people to the occurrence of simulated sonic booms in their homes. The system provided a degree of control over the noise exposure not found in community surveys and a degree of situational realism not available in the laboratory. A system was deployed for eight weeks in each of 33 homes. Each day from 4 to 63 sonic booms were played as the test subject went about his or her normal activities. At the end of the day, the test subjects rated their annoyance to the sonic booms heard during the day. The sonic booms consisted of different combinations of waveforms, levels, and occurrence rates. The experiment confirmed that the increase in annoyance resulting from multiple occurrences can be modeled by the addition of the term "10 * log(number of occurrences)" to the sonic boom level. Of several noise metrics considered, perceived level was the best annoyance predictor. Comparisons of the subjective responses to the different sonic boom waveforms found no differences that were not accounted for by the noise metrics. PMID:15478423

  9. Subjective response of people to simulated sonic booms in their homes

    NASA Technical Reports Server (NTRS)

    McCurdy, David A.; Brown, Sherilyn A.; Hilliard, R. David

    2004-01-01

    In order to determine the effect of the number of sonic boom occurrences on annoyance, a computer-based system was developed for studying the subjective response of people to the occurrence of simulated sonic booms in their homes. The system provided a degree of control over the noise exposure not found in community surveys and a degree of situational realism not available in the laboratory. A system was deployed for eight weeks in each of 33 homes. Each day from 4 to 63 sonic booms were played as the test subject went about his or her normal activities. At the end of the day, the test subjects rated their annoyance to the sonic booms heard during the day. The sonic booms consisted of different combinations of waveforms, levels, and occurrence rates. The experiment confirmed that the increase in annoyance resulting from multiple occurrences can be modeled by the addition of the term "10 * log(number of occurrences)" to the sonic boom level. Of several noise metrics considered, perceived level was the best annoyance predictor. Comparisons of the subjective responses to the different sonic boom waveforms found no differences that were not accounted for by the noise metrics.

  10. Subjective response to sonic booms having different shapes, rise times, and durations

    NASA Technical Reports Server (NTRS)

    Mccurdy, David A.

    1994-01-01

    Two laboratory experiments were conducted to quantify the subjective response of people to simulated outdoor sonic booms having different pressure signatures. The specific objectives of the experiments were to compare subjective response to sonic booms when described in terms of 'loudness' and 'annoyance'; to determine the ability of various noise metrics to predict subjective response to sonic booms; to determine the effects on subjective response of rise time, duration, and level; and to compare the subjective response to 'N-wave' sonic boom signatures with the subjective response to 'minimized' sonic boom signatures. The experiments were conducted in a computer-controlled, man-rated sonic boom simulator capable of reproducing user-specified pressure signatures for a wide range of sonic boom parameters. One hundred and fifty sonic booms representing different combinations of two wave shapes, four rise times, seven durations, and three peak overpressures were presented to 36 test subjects in each experiment. The test subjects in the first experiment made judgments of 'loudness' while the test subjects in the second experiment judged 'annoyance.' Subjective response to sonic booms was the same whether expressed in terms of loudness or in terms of annoyance. Analyses of several different noise metrics indicated that A-weighted sound exposure level and Perceived Level were the best predictors of subjective response. Further analyses indicated that, of these two noise metrics, only Perceived Level completely accounted for the effects of wave shape, rise time, and peak overpressure. Neither metric fully accounted for the effect of duration. However, the magnitude of the duration effect was small over the very wide range of durations considered.

  11. An in-home study of subjective response to simulated sonic booms

    NASA Technical Reports Server (NTRS)

    Mccurdy, David A.; Brown, Sherilyn A.; Hilliard, R. David

    1994-01-01

    The proposed development of a second-generation supersonic commercial transport has resulted in increased research efforts to provide an environmentally acceptable aircraft. One of the environmental issues is the impact of sonic booms on people. Aircraft designers are attempting to design the transport to produce sonic boom signatures that will have minimum impact on the public. Current supersonic commercial aircraft produce an 'N-wave' sonic boom pressure signature that is considered unacceptable by the public. This has resulted in first-generation supersonic transports being banned from flying supersonically over land in the United States, a severe economic constraint. By tailoring aircraft volume and lift distributions, designers hope to produce sonic boom signatures having specific shapes other than 'N-wave' that may be more acceptable to the public and could possibly permit overland supersonic flight. As part of the effort to develop a second-generation supersonic commercial transport, Langley Research Center is conducting research to study people's subjective response to sonic booms. As part of that research, a system was developed for performing studies of the subjective response of people to the occurrence of simulated sonic booms in their homes. The In-Home Noise Generation/Response System (IHONORS) provides a degree of situational realism not available in the laboratory and a degree of control over the noise exposure not found in community surveys. The computer-controlled audio system generates the simulated sonic booms, measures the noise levels, and records the subjects' rating and can be placed and operated in individuals' homes for extended periods of time. The system was used to conduct an in-home study of subjective response to simulated sonic booms. The primary objective of the study was to determine the effect on annoyance of the number of sonic boom occurrences in a realistic environment.

  12. Sonic boom measurement test plan for Space Shuttle STS-1 reentry

    NASA Technical Reports Server (NTRS)

    Henderson, H. R.

    1981-01-01

    Formal documentation for measurement procedures and system specifications, and general information are relating to the Space Shuttle STS-1 Sonic Boom Measurement Program are supplied. This test plan is designed to provide information, guidance, and assignment of responsibilities for the acquisition of sonic boom and atmospheric measurements, timing correlation, communications and other necessary supporting tasks. Specifically included are details such as mobile data acquisition station locations, measurement systems calibration levels, predicted sonic boom overpressure levels, overpressure level assignment for each data acquisition station, data recording times on and off, universal coordinated time, and measurement system descriptions.

  13. Sonic boom measurement test plan for Space Shuttle STS-4 reentry

    NASA Technical Reports Server (NTRS)

    Henderson, H. R.

    1982-01-01

    Formal documentation for measurement procedures and system specifications, and general information relating to the Space Shuttle STS-4 Sonic Boom Measurement Program are supplied. This test plan is designed to provide information, guidance, and assignment of responsibilities for the acquisition of sonic boom and atmospheric measurements, timing correlation, communications and other necessary supporting tasks. Specifically included are details such as mobile data acquisition station locations, measurement systems calibration levels, predicted sonic boom overpressure levels, overpressure level assignment for each data acquisition station, data recording times on and off, universal coordinated time, and measurement system descriptions.

  14. Laboratory study of sonic booms and their scaling laws. [ballistic range simulation

    NASA Technical Reports Server (NTRS)

    Toong, T. Y.

    1974-01-01

    This program undertook to seek a basic understanding of non-linear effects associated with caustics, through laboratory simulation experiments of sonic booms in a ballistic range and a coordinated theoretical study of scaling laws. Two cases of superbooms or enhanced sonic booms at caustics have been studied. The first case, referred to as acceleration superbooms, is related to the enhanced sonic booms generated during the acceleration maneuvers of supersonic aircrafts. The second case, referred to as refraction superbooms, involves the superbooms that are generated as a result of atmospheric refraction. Important theoretical and experimental results are briefly reported.

  15. Evaluation of outdoor-to-indoor response to minimized sonic booms

    NASA Technical Reports Server (NTRS)

    Brown, David; Sutherland, Louis C.

    1992-01-01

    Various studies were conducted by NASA and others on the practical limitations of sonic boom signature shaping/minimization for the High-Speed Civil Transport (HSCT) and on the effects of these shaped boom signatures on perceived loudness. This current effort is a further part of this research with emphasis on examining shaped boom signatures which are representative of the most recent investigations of practical limitations on sonic boom minimization, and on examining and comparing the expected response to these signatures when experienced indoors and outdoors.

  16. Predicting transmission of shaped sonic booms into a residential house structure.

    PubMed

    Sizov, Natalia V; Plotkin, Kenneth J; Hobbs, Christopher M

    2010-06-01

    Human perception of sonic booms is a major impediment to commercial supersonic flight. Shaping, which reduces the audible shock waves of a boom, can make outdoor perception of booms acceptable. Perception of sonic booms experienced indoors is of concern, and it is not yet established whether shaped booms offer benefit to indoor listeners. A better understanding of the transmission of shaped booms into building structures is needed. In the authors' earlier work the vibration response of house elements subjected to different sonic boom wave shapes was evaluated using a single degree of freedom model. This paper expands that approach with a modal analysis model. The acceleration of building elements and the resulting sound pressure inside a room are computed in the time and frequency domains. Analytical results are compared with experimental data measured by NASA during sonic boom tests conducted at Edwards Air Force Base in 2007. The effects of wave signature parameters on transmission are studied to evaluate the advantages of various kinds of minimized boom shapes. PMID:20550235

  17. Flight Demonstration Of Low Overpressure N-Wave Sonic Booms And Evanescent Waves

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.; Smolka, James W.; Murray, James E.; Plotkin, Kenneth J.

    2005-01-01

    The recent flight demonstration of shaped sonic booms shows the potential for quiet overland supersonic flight, which could revolutionize air transport. To successfully design quiet supersonic aircraft, the upper limit of an acceptable noise level must be determined through quantitative recording and subjective human response measurements. Past efforts have concentrated on the use of sonic boom simulators to assess human response, but simulators often cannot reproduce a realistic sonic boom sound. Until now, molecular relaxation effects on low overpressure rise time had never been compared with flight data. Supersonic flight slower than the cutoff Mach number, which generates evanescent waves, also prevents loud sonic booms from impacting the ground. The loudness of these evanescent waves can be computed, but flight measurement validation is needed. A novel flight demonstration technique that generates low overpressure N-waves using conventional military aircraft is outlined, in addition to initial quantitative flight data. As part of this demonstration, evanescent waves also will be recorded.

  18. Flight Demonstration Of Low Overpressure N-Wave Sonic Booms And Evanescent Waves

    NASA Astrophysics Data System (ADS)

    Haering, Edward A.; Smolka, James W.; Murray, James E.; Plotkin, Kenneth J.

    2006-05-01

    The recent flight demonstration of shaped sonic booms shows the potential for quiet overland supersonic flight, which could revolutionize air transport. To successfully design quiet supersonic aircraft, the upper limit of an acceptable noise level must be determined through quantitative recording and subjective human response measurements. Past efforts have concentrated on the use of sonic boom simulators to assess human response, but simulators often cannot reproduce a realistic sonic boom sound. Until now, molecular relaxation effects on low overpressure rise time had never been compared with flight data. Supersonic flight slower than the cutoff Mach number, which generates evanescent waves, also prevents loud sonic booms from impacting the ground. The loudness of these evanescent waves can be computed, but flight measurement validation is needed. A novel flight demonstration technique that generates low overpressure N-waves using conventional military aircraft is outlined, in addition to initial quantitative flight data. As part of this demonstration, evanescent waves also will be recorded.

  19. Study to determine seismic response of sonic boom-coupled Rayleigh waves

    NASA Astrophysics Data System (ADS)

    Legg, Mark R.; Haber, Jerold M.

    1990-05-01

    A literature search was performed regarding the seismic effects of sonic booms with emphasis on the coupled Rayleigh wave resonance phenomenon. The literature search covered 3 primary sources of information: (1) Air Force Environmental Impact Assessment Documents, (2) litigation and claims, and (3) open scientific literature. The literature regarding sonic boom structural damage was reviewed under Task Order 0010. The investigations of seismic waves induced by sonic booms found the amplitudes of the ground motion insufficient to damage structures. Few instances were reported, however, where the actual resonant conditions of the sonic boom-coupled Rayleigh wave were observed. The ground motion amplification accompanying the resonance documented in these cases did not reach damaging levels. Nevertheless, it is theoretically possible that conditions exist which could result in damaging levels of ground shaking. In order to define under what specific conditions, if any, such resonance could occur, an additional literature review was conducted.

  20. Langley's Computational Efforts in Sonic-Boom Softening of the Boeing HSCT

    NASA Technical Reports Server (NTRS)

    Fouladi, Kamran

    1999-01-01

    NASA Langley's computational efforts in the sonic-boom softening of the Boeing high-speed civil transport are discussed in this paper. In these efforts, an optimization process using a higher order Euler method for analysis was employed to reduce the sonic boom of a baseline configuration through fuselage camber and wing dihedral modifications. Fuselage modifications did not provide any improvements, but the dihedral modifications were shown to be an important tool for the softening process. The study also included aerodynamic and sonic-boom analyses of the baseline and some of the proposed "softened" configurations. Comparisons of two Euler methodologies and two propagation programs for sonic-boom predictions are also discussed in the present paper.

  1. Development of Multiobjective Optimization Techniques for Sonic Boom Minimization

    NASA Technical Reports Server (NTRS)

    Chattopadhyay, Aditi; Rajadas, John Narayan; Pagaldipti, Naryanan S.

    1996-01-01

    improve the aerodynamic, the sonic boom and the structural characteristics of the aircraft. The flow solution is obtained using a comprehensive parabolized Navier Stokes solver. Sonic boom analysis is performed using an extrapolation procedure. The aircraft wing load carrying member is modeled as either an isotropic or a composite box beam. The isotropic box beam is analyzed using thin wall theory. The composite box beam is analyzed using a finite element procedure. The developed optimization procedures yield significant improvements in all the performance criteria and provide interesting design trade-offs. The semi-analytical sensitivity analysis techniques offer significant computational savings and allow the use of comprehensive analysis procedures within design optimization studies.

  2. Reactions to sonic booms: a report of two studies and a general evaluation of startle effects.

    PubMed

    Thackray, R I; Touchstone, R M; Bailey, J P

    1975-04-01

    Two separate studies are reported. The first attempted to determine a sonic boom level below which startle would not occurr. Subjects were exposed indoors to six simulated sonic booms having outside overpressures of 50, 30, and 16 N/m-2 (inside levels of 74, 71, and 65 dBA). Approximately 20% of the subjects gave small arm-hand responses to the two higher exposure levels, while none responded to the lowest level. In the second study, subjects were exposed indoors to a series of 12 simulated booms in order to assess habituation effects. Outside overpressures were 130 and 50 N/m-2 (indoor levels of 81 and 72 dBA). Significant, but not complete, habituation occurred to booms of both levels. Autonomic and eyeblink responses, as well as ratings of annoyance, were obtained in both studies. The final section summarizes the expected behavioral, autonomic, and subjective effects of exposure to various levels of sonic booms. PMID:1147871

  3. Output-Adaptive Tetrahedral Cut-Cell Validation for Sonic Boom Prediction

    NASA Technical Reports Server (NTRS)

    Park, Michael A.; Darmofal, David L.

    2008-01-01

    A cut-cell approach to Computational Fluid Dynamics (CFD) that utilizes the median dual of a tetrahedral background grid is described. The discrete adjoint is also calculated, which permits adaptation based on improving the calculation of a specified output (off-body pressure signature) in supersonic inviscid flow. These predicted signatures are compared to wind tunnel measurements on and off the configuration centerline 10 body lengths below the model to validate the method for sonic boom prediction. Accurate mid-field sonic boom pressure signatures are calculated with the Euler equations without the use of hybrid grid or signature propagation methods. Highly-refined, shock-aligned anisotropic grids were produced by this method from coarse isotropic grids created without prior knowledge of shock locations. A heuristic reconstruction limiter provided stable flow and adjoint solution schemes while producing similar signatures to Barth-Jespersen and Venkatakrishnan limiters. The use of cut-cells with an output-based adaptive scheme completely automated this accurate prediction capability after a triangular mesh is generated for the cut surface. This automation drastically reduces the manual intervention required by existing methods.

  4. Global variation of sonic boom overpressure due to seasonal changes in atmosphere

    NASA Astrophysics Data System (ADS)

    Yamashita, Hiroshi; Obayashi, Shigeru

    2012-09-01

    Global variation of sonic boom overpressures with the realistic atmospheric gradients was discussed. The atmospheric gradients were estimated by upper-air observational radiosonde data and a simple N-wave was extrapolated through all seasonal atmospheric gradients without winds around the world. Results demonstrated that sonic boom overpressure varies widely with season and geographic position compared to that of the standard atmospheric condition. The results also showed the tendencies of the global variation in overpressure.

  5. Residents' reactions to long-term sonic boom exposure: Preliminary results

    NASA Technical Reports Server (NTRS)

    Fields, James M.; Moulton, Carey; Baumgartner, Robert M.; Thomas, Jeff

    1994-01-01

    This presentation is about residents' reactions to sonic booms in a long-term sonic boom exposure environment. Although two phases of the data collection have been completed, the analysis of the data has only begun. The results are thus preliminary. The list of four authors reflects the complex multi-disciplinary character of any field study such as this one. Carey Moulton is responsible for Wyle Laboratories' acoustical data collection effort. Robert Baumgartner and Jeff Thomas of HBRS, a social science research firm, are responsible for social survey field work and data processing. The study is supported by the NASA Langley Research Center. The study has several objectives. The preliminary data addresses two of the primary objectives. The first objective is to describe the reactions to sonic booms of people who are living where sonic booms are a routine, recurring feature of the acoustical environment. The second objective is to compare these residents' reactions to the reactions of residents who hear conventional aircraft noise around airports. Here is an overview of the presentation. This study will first be placed in the context of previous community survey research on sonic booms. Next the noise measurement program will be briefly described and part of a social survey interview will be presented. Finally data will be presented on the residents' reactions and these reactions will be compared with reactions to conventional aircraft. Twelve community studies of residents' reactions to sonic booms were conducted in the United States and Europe in the 1960's and early 1970's. None of the 12 studies combined three essential ingredients that are found in the present study. Residents' long-term responses are related to a measured noise environment. Sonic booms are a permanent feature of the residential environment. The respondents' do not live on a military base. The present study is important because it provides the first dose/response relationship for sonic booms

  6. Sonic boom measurement test plan for Space Shuttle STS-3 reentry

    NASA Technical Reports Server (NTRS)

    Henderson, H. R.

    1982-01-01

    The lateral area from the reentry ground track affected by sonic boom overpressure levels is determined. Four data acquisition stations are deployed laterally to the STS-3 reentry flight track. These stations provide six intermediate band FM channels of sonic boom data, universal time synchronization, and voice annotation. All measurements are correlated with the vehicle reentry flight track information along with atmospheric and vehicle operation conditions.

  7. An analysis of the response of Sooty Tern eggs to sonic boom overpressures

    NASA Astrophysics Data System (ADS)

    Ting, Carina; Garrelick, Joel; Bowles, Ann

    2002-01-01

    It has been proposed that sonic booms caused a mass hatching failure of Sooty Terns in the Dry Tortugas in Florida by cracking the eggshells. This paper investigates this possibility analytically, complementing previous empirical studies. The sonic boom is represented as a plane-wave excitation with an N-wave time signature. Two models for the egg are employed. The first model, intended to provide insight, consists of a spherical shell, with the embryo represented as a rigid, concentric sphere and the albumen as an acoustic fluid filling the intervening volume. The substrate is modeled as a doubling of the incident pressure. The second, numerical model includes the egg-shape geometry and air sac. More importantly, the substrate is modeled as a rigid boundary of infinite extent with acoustic diffraction included. The peak shell stress, embryo acceleration, and reactive force are predicted as a function of the peak sonic boom overpressure and compared with damage criteria from the literature. The predicted peak sonic boom overpressure necessary for egg damage is much higher than documented sonic boom overpressures, even for extraordinary operational conditions. Therefore, as with previous empirical studies, it is concluded that it is unlikely that sonic boom overpressures damage avian eggs.

  8. Preliminary airborne measurements for the SR-71 sonic boom propagation experiment

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.; Ehernberger, L. J.; Whitmore, Stephen A.

    1995-01-01

    SR-71 sonic boom signatures were measured to validate sonic boom propagation prediction codes. An SR-71 aircraft generated sonic booms from Mach 1.25 to Mach 1.6, at altitudes of 31,000 to 48,000 ft, and at various gross weights. An F-16XL aircraft measured the SR-71 near-field shock waves from close to the aircraft to more than 8,000 ft below, gathering 105 signatures. A YO-3A aircraft measured the SR-71 sonic booms from 21,000 to 38,000 feet below, recording 17 passes. The sonic booms at ground level and atmospheric data were recorded for each flight. Data analysis is underway. Preliminary results show that shock wave patterns and coalescence vary with SR-71 gross weight, Mach number, and altitude. For example, noncoalesced shock wave signatures were measured by the YO-3A at 21,000 ft below the SR-71 aircraft while at a low gross weight, Mach 1.25, and 31,000-ft altitude. This paper describes the design and execution of the flight research experiment. Instrumentation and flight maneuvers of the SR-71, F-16XL, and YO-3A aircraft and sample sonic boom signatures are included.

  9. An analysis of the response of Sooty Tern eggs to sonic boom overpressures.

    PubMed

    Ting, Carina; Garrelick, Joel; Bowles, Ann

    2002-01-01

    It has been proposed that sonic booms caused a mass hatching failure of Sooty Terns in the Dry Tortugas in Florida by cracking the eggshells. This paper investigates this possibility analytically, complementing previous empirical studies. The sonic boom is represented as a plane-wave excitation with an N-wave time signature. Two models for the egg are employed. The first model, intended to provide insight, consists of a spherical shell, with the embryo represented as a rigid, concentric sphere and the albumen as an acoustic fluid filling the intervening volume. The substrate is modeled as a doubling of the incident pressure. The second, numerical model includes the egg-shape geometry and air sac. More importantly, the substrate is modeled as a rigid boundary of infinite extent with acoustic diffraction included. The peak shell stress, embryo acceleration, and reactive force are predicted as a function of the peak sonic boom overpressure and compared with damage criteria from the literature. The predicted peak sonic boom overpressure necessary for egg damage is much higher than documented sonic boom overpressures, even for extraordinary operational conditions. Therefore, as with previous empirical studies, it is concluded that it is unlikely that sonic boom overpressures damage avian eggs. PMID:11837961

  10. A computational analysis of sonic booms penetrating a realistic ocean surface.

    PubMed

    Rochat, J L; Sparrow, V W

    2001-03-01

    The last decade has seen a revival of sonic boom research, a direct result of the projected market for a new breed of supersonic passenger aircraft, its design, and its operation. One area of the research involves sonic boom penetration into the ocean, one concern being the possible disturbance of marine mammals from the noise generated by proposed high-speed civil transport (HSCT) flyovers. Although theory is available to predict underwater sound levels due to a sonic boom hitting a homogeneous ocean with a flat surface, theory for a realistic ocean, one with a wavy surface and bubbles near the surface, is missing and will be presented in this paper. First, reviews are given of a computational method to calculate the underwater pressure field and the effects of a simple wavy ocean surface on the impinging sonic boom. Second, effects are described for the implementation of three additional conditions: a sonic boom/ocean "wavelength" comparison, complex ocean surfaces, and bubbles near the ocean surface. Overall, results from the model suggest that the realistic ocean features affect the penetrating proposed HSCT sonic booms by modifying the underwater sound-pressure levels only about 1 decibel or less. PMID:11303944

  11. Evaluation of human response to structural vibrations induced by sonic booms

    NASA Technical Reports Server (NTRS)

    Sutherland, Louis C.; Czech, J.

    1992-01-01

    The topic is addressed of building vibration response to sonic boom and the evaluation of the associated human response to this vibration. An attempt is made to reexamine some of the issues addressed previously and to offer fresh insight that may assist in reassessing the potential impact of sonic boom over populated areas. Human response to vibration is reviewed first and a new human vibration response criterion curve is developed as a function of frequency. The difference between response to steady state versus impulsive vibration is addressed and a 'vibration exposure' or 'vibration energy' descriptor is suggested as one possible way to evaluate duration effects on response to transient vibration from sonic booms. New data on the acoustic signature of rattling objects are presented along with a review of existing data on the occurrence of rattle. Structural response to sonic boom is reviewed and a new descriptor, 'Acceleration Exposure Level' is suggested which can be easily determined from the Fourier Spectrum of a sonic boom. A preliminary assessment of potential impact from sonic booms is provided in terms of human response to vibration and detection of rattle based on a synthesis of the preceding material.

  12. Using CFD Surface Solutions to Shape Sonic Boom Signatures Propagated from Off-Body Pressure

    NASA Technical Reports Server (NTRS)

    Ordaz, Irian; Li, Wu

    2013-01-01

    The conceptual design of a low-boom and low-drag supersonic aircraft remains a challenge despite significant progress in recent years. Inverse design using reversed equivalent area and adjoint methods have been demonstrated to be effective in shaping the ground signature propagated from computational fluid dynamics (CFD) off-body pressure distributions. However, there is still a need to reduce the computational cost in the early stages of design to obtain a baseline that is feasible for low-boom shaping, and in the search for a robust low-boom design over the entire sonic boom footprint. The proposed design method addresses the need to reduce the computational cost for robust low-boom design by using surface pressure distributions from CFD solutions to shape sonic boom ground signatures propagated from CFD off-body pressure.

  13. Subjective loudness of N-wave sonic booms.

    PubMed

    Niedzwiecki, A; Ribner, H S

    1978-12-01

    A loudspeaker-driven simulation booth with extended rise-time capability (down to 0.22 ms) has been used for subjective loudness tests of N-wave sonic booms. The test series compared signatures over a range of 0.22--10 ms in rise time, 100--250 ms in duration and 0.5--2.5 psf (24--120 Pa) in peak overpressure. In one sequence, the tradeoff between rise time and overpressure was measured for equal loudness; in another, the tradeoff between duration and overpressure. For equal loudness 10-ms rise time required 8-dB higher overpressure than for 1-ms rise time. Duration had little effect in the range 100--200 ms, but at 250 ms noticeably enhanced the loudness. These results confirm those measured by Shepherd and Sutherland made at 1-ms rise time and above (except for the anomalous enhancement at 250-ms duration), and extend the measurements down to 0.22 ms. There is also good agreement with theoretical predictions (Johnson-Robinson, Zepler-Harel methods) except for the 10-ms rise time and 250-ms duration cases. PMID:739096

  14. A sonic boom propagation model including mean flow atmospheric effects

    NASA Astrophysics Data System (ADS)

    Salamone, Joe; Sparrow, Victor W.

    2012-09-01

    This paper presents a time domain formulation of nonlinear lossy propagation in onedimension that also includes the effects of non-collinear mean flow in the acoustic medium. The model equation utilized is an augmented Burgers equation that includes the effects of nonlinearity, geometric spreading, atmospheric stratification, and also absorption and dispersion due to thermoviscous and molecular relaxation effects. All elements of the propagation are implemented in the time domain and the effects of non-collinear mean flow are accounted for in each term of the model equation. Previous authors have presented methods limited to showing the effects of wind on ray tracing and/or using an effective speed of sound in their model equation. The present work includes the effects of mean flow for all terms included in the augmented Burgers equation with all of the calculations performed in the time-domain. The capability to include the effects of mean flow in the acoustic medium allows one to make predictions more representative of real-world atmospheric conditions. Examples are presented for nonlinear propagation of N-waves and shaped sonic booms. [Work supported by Gulfstream Aerospace Corporation.

  15. Interaction of the sonic boom with atmospheric turbulence

    NASA Technical Reports Server (NTRS)

    Rusak, Zvi; Cole, Julian D.

    1994-01-01

    Theoretical research was carried out to study the effect of free-stream turbulence on sonic boom pressure fields. A new transonic small-disturbance model to analyze the interactions of random disturbances with a weak shock was developed. The model equation has an extended form of the classic small-disturbance equation for unsteady transonic aerodynamics. An alternative approach shows that the pressure field may be described by an equation that has an extended form of the classic nonlinear acoustics equation that describes the propagation of sound beams with narrow angular spectrum. The model shows that diffraction effects, nonlinear steepening effects, focusing and caustic effects and random induced vorticity fluctuations interact simultaneously to determine the development of the shock wave in space and time and the pressure field behind it. A finite-difference algorithm to solve the mixed type elliptic-hyperbolic flows around the shock wave was also developed. Numerical calculations of shock wave interactions with various deterministic and random fluctuations will be presented in a future report.

  16. Statistical and numerical study of the relation between weather and sonic boom characteristics

    NASA Technical Reports Server (NTRS)

    Yao, Lixin; Bass, Henry E.; Raspet, Richard; Mcbride, Walton E.

    1992-01-01

    NASA measured sonic boom characteristics near Edwards Air Force Base from 11/66 to 1/67. Thirty four flights by an F-104 were recorded at an altitude of about 31,000 feet and flying speed of Mach 1.3. Forty two microphones were placed on the ground directly under the fight track. Each microphone recorded boom shape, rise time, peak overpressure, total boom duration, positive duration, and positive impulse.

  17. Wind Tunnel Model Design for Sonic Boom Studies of Nozzle Jet Flows with Shock Interactions

    NASA Technical Reports Server (NTRS)

    Cliff, Susan E.; Denison, Marie; Moini-Yekta, Shayan; Morr, Donald E.; Durston, Donald A.

    2016-01-01

    NASA and the U.S. aerospace industry are performing studies of supersonic aircraft concepts with low sonic boom pressure signatures. The computational analyses of modern aircraft designs have matured to the point where there is confidence in the prediction of the pressure signature from the front of the vehicle, but uncertainty remains in the aft signatures due to boundary layer and nozzle exhaust jet effects. Wind tunnel testing without inlet and nozzle exhaust jet effects at lower Reynolds numbers than in-flight make it difficult to accurately assess the computational solutions of flight vehicles. A wind tunnel test in the NASA Ames 9- by 7-Foot Supersonic Wind Tunnel is planned for February 2016 to address the nozzle jet effects on sonic boom. The experiment will provide pressure signatures of test articles that replicate waveforms from aircraft wings, tails, and aft fuselage (deck) components after passing through cold nozzle jet plumes. The data will provide a variety of nozzle plume and shock interactions for comparison with computational results. A large number of high-fidelity numerical simulations of a variety of shock generators were evaluated to define a reduced collection of suitable test models. The computational results of the candidate wind tunnel test models as they evolved are summarized, and pre-test computations of the final designs are provided.

  18. A Flight Research Overview of WSPR, a Pilot Project for Sonic Boom Community Response

    NASA Technical Reports Server (NTRS)

    Cliatt, Larry James; Haering, Ed; Jones, Thomas P.; Waggoner, Erin R.; Flattery, Ashley K.; Wiley, Scott L.

    2014-01-01

    In support of NASAs ongoing effort to bring supersonic commercial travel to the public, NASA Dryden Flight Research Center and NASA Langley Research Center, in cooperation with other industry organizations, conducted a flight research experiment to identify the methods, tools, and best practices for a large-scale quiet (or low) sonic boom community human response test. The name of the effort was Waveforms and Sonic boom Perception and Response. Such tests will go towards building a dataset that governing agencies like the Federal Aviation Administration and International Civil Aviation Organization will use to establish regulations for acceptable sound levels of overland sonic booms. Until WSPR, there had never been an effort that studied the response of people in their own homes and performing daily activities to non-traditional, low sonic booms.WSPR was a NASA collaborative effort with several industry partners, in response to a NASA Aeronautics Research Mission Directorate Research Opportunities in Aeronautics. The primary contractor was Wyle. Other partners included Gulfstream Aerospace Corporation, Pennsylvania State University, Tetra Tech, and Fidell Associates, Inc.A major objective of the effort included exposing a community with the sonic boom magnitudes and occurrences expected in high-air traffic regions with a network of supersonic commercial aircraft in place. Low-level sonic booms designed to simulate those produced by the next generation of commercial supersonic aircraft were generated over a small residential community. The sonic boom footprint was recorded with an autonomous wireless microphone array that spanned the entire community. Human response data was collected using multiple survey methods. The research focused on essential elements of community response testing including subject recruitment, survey methods, instrumentation systems, flight planning and operations, and data analysis methods.This paper focuses on NASAs role in the efforts

  19. A Flight Research Overview of WSPR, a Pilot Project for Sonic Boom Community Response

    NASA Technical Reports Server (NTRS)

    Cliatt, Larry J., II; Haering, Edward A., Jr.; Jones, Thomas P.; Waggoner, Erin R.; Flattery, Ashley K.; Wiley, Scott L.

    2014-01-01

    In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, the NASA Armstrong Flight Research Center and the NASA Langley Research Center, in cooperation with other industry organizations, conducted a flight research experiment to identify the methods, tools, and best practices for a large-scale quiet (or low) sonic boom community human response test. The name of the effort was Waveforms and Sonic boom Perception and Response (WSPR). Such tests will be applied to building a dataset that governing agencies such as the Federal Aviation Administration and the International Civil Aviation Organization will use to establish regulations for acceptable sound levels of overland sonic booms. The WSPR test was the first such effort that studied responses to non-traditional low sonic booms while the subject persons were in their own homes and performing daily activities.The WSPR test was a NASA collaborative effort with several industry partners, in response to a NASA Aeronautics Research Mission Directorate Research Opportunities in Aeronautics. The primary contractor was Wyle (El Segundo, California). Other partners included Gulfstream Aerospace Corporation (Savannah, Georgia); Pennsylvania State University (University Park, Pennsylvania); Tetra Tech, Inc. (Pasadena, California); and Fidell Associates, Inc. (Woodland Hills, California).A major objective of the effort included exposing a community to the sonic boom magnitudes and occurrences that would be expected to occur in high-air traffic regions having a network of supersonic commercial aircraft in place. Low-level sonic booms designed to simulate those produced by the next generation of commercial supersonic aircraft were generated over a small residential community. The sonic boom footprint was recorded with an autonomous wireless microphone array that spanned the entire community. Human response data were collected using multiple

  20. The American Environmental Movement's Lost Victory: The Fight against Sonic Booms.

    PubMed

    Suisman, David

    2015-11-01

    Political contestation over sound can take many forms, with profound consequences for the aural environment. One example is found in the battles over the sonic booms associated with the US government's supersonic transport (SST) program in the 1960s and early 1970s--a program that had it been realized, would have filled the everyday soundscape with thunderous sonic blasts. This article analyzes the individuals and groups who mobilized against sonic booms and the SST and the activists' unlikely success over the SST in 1971. Today, this victory stands as an important, if largely forgotten, victory of the early environmental movement. PMID:26720994

  1. Evaluation of human response to structural vibration induced by sonic boom

    NASA Technical Reports Server (NTRS)

    Sutherland, L. C.; Czech, J.

    1992-01-01

    This paper addresses the topic of building vibration response to sonic boom and the evaluation of the associated human response to this vibration. The paper reexamines some of the issues addressed in the previous extensive coverage of the topic, primarily by NASA, and attempts to offer a fresh viewpoint for some of the problems that may assist in reassessing the potential impact of sonic boom over populated areas. The topics addressed are: (1) human response to vibration; (2) criteria for, and acoustic signature of rattle; (3) structural response to shaped booms, including definition of two new descriptors for assessing the structural response to sonic boom; and (4) a detailed review of the previous NASA/FAA Sonic Boom Test Program involving structural response measurements at Edwards AFB and an initial estimate of structural response to sonic booms from possible high speed civil transport configurations. Finally, these estimated vibration responses are shown to be substantially greater than the human response and rattle criteria developed earlier.

  2. USAF Flight Test Investigation of Focused Sonic Booms: Project Have Bears

    NASA Technical Reports Server (NTRS)

    Downing, Micah; Zamot, Noel; Moss, Chris; Morin, Daniel; Wolski, Ed; Chung, Sukhwan; Plotkin, Kenneth; Maglieri, Domenic

    1996-01-01

    Supersonic operations from military aircraft generate sonic booms that can affect people, animals and structures. A substantial experimental data base exists on sonic booms for aircraft in steady flight and confidence in the predictive techniques has been established. All the focus sonic boom data that are in existence today were collected during the 60's and 70's as part of the information base to the US Supersonic Transport program and the French Jericho studies for the Concorde. These experiments formed the data base to develop sonic boom propagation and prediction theories for focusing. There is a renewed interest in high-speed transports for civilian application. Moreover, today's fighter aircraft have better performance capabilities, and supersonic flights ars more common during air combat maneuvers. Most of the existing data on focus booms are related to high-speed civil operations such as transitional linear accelerations and mild turns. However, military aircraft operating in training areas perform more drastic maneuvers such as dives and high-g turns. An update and confirmation of USAF prediction capabilities is required to demonstrate the ability to predict and control sonic boom impacts, especially those produced by air combat maneuvers.

  3. Noise and sonic-boom impact technology. BOOMAP2 computer program for sonic-boom research. Volume 1. Technical report. Final report, July 1986-November 1987

    SciTech Connect

    Wilby, E.G.; Haber, J.M.; Bishop, D.E.

    1988-08-01

    The BOOMAP2 and MOAOPS computer programs analyze noise from supersonic aircraft-operations by extracting information from the ACMI/TACTS computer tapes. The MOAOPS program extracts information from a TACTS/ACMI mission standard data tape and compiles a computer library of information concerning the supersonic operations. The BOOMAP2 program utilizes the library produced by the MOAOPS program. The program calculates various statistics on the supersonic operations and calculates expected sonic boom levels on the ground based on the extracted information. BOOMAP2 can: (1) generate various spatial/temporal distribution statistics; (2) interface with sonic-boom generation and propagation models; (3) calculate the intensity and location of sonic booms reaching the ground; and (4) provide the data file used by a commercial graphical software package, GRCP, to plot contours of boom exposure in units of average peak overpressure or C-weighted day-night average sound level (CDNL). These two programs, when used with an adequate library of aircraft sorties from Military Operating Areas, can be an invaluable tool for environmental planning purposes to predict boom intensity, frequency, and distribution. This report describes the technical basis for the BOOMAP2 program developed under this contract.

  4. The effect of turbulence on the loudness of minimized sonic boom signatures

    NASA Technical Reports Server (NTRS)

    Plotkin, Kenneth J.

    1992-01-01

    An important issue for shaped minimized sonic booms is whether turbulence-induced distortions will adversely affect the benefits gained by shaping. This question was considerably simplified by two recent results. The first is the finding that the loudness of sonic booms is well quantified by loudness. The second is that loudness of a shaped boom is dominated by the shock waves. The issue is now the effect of turbulence on weak (1 psf or less) sonic booms. Since it is clear that molecular relaxation effects have a significant effect on shock structure and loudness, turbulence effects must be examined in conjunction with relaxation-thickened shocks. This analysis must be directed toward loudness calculations and include all pertinent mechanisms.

  5. An Integrated Fuselage-Sting Balance for a Sonic-Boom Wind-Tunnel Model

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    2004-01-01

    Measured and predicted pressure signatures from a lifting wind-tunnel model can be compared when the lift on the model is accurately known. The model's lift can be set by bending the support sting to a desired angle of attack. This method is simple in practice, but difficult to accurately apply. A second method is to build a normal force/pitching moment balance into the aft end of the sting, and use an angle-of-attack mechanism to set model attitude. In this report, a method for designing a sting/balance into the aft fuselage/sting of a sonic-boom model is described. A computer code is given, and a sample sting design is outlined to demonstrate the method.

  6. Sonic booms produced by US Air Force and US Navy aircraft: Measured data

    NASA Astrophysics Data System (ADS)

    Lee, R. A.; Downing, J. M.

    1991-01-01

    A sonic measurement program was conducted at Edwards Air Force Base. Sonic boom signatures, produced by F-4, F-14, F-15, F-16, F-18, F-111, SR-71, and T-38 aircraft, were obtained under the flight track and at various lateral sites which were located up to 18 miles off-track. Thirteen monitors developed by Det 1 AL/BBE were used to collect full sonic boom waveforms, and nine modified dosimeters were used to collect supplemental peak overpressures and the C-weighted Sound Exposure Levels (CSEL) for 43 near steady supersonic flights of the above United States Air Force and United States Navy aircraft. This report describes the measured database (BOOMFILE) that contains sonic boom signatures and overpressures, aircraft tracking, and local weather data. These measured data highlight the major influences on sonic boom propagation and generation. The data from this study show that a constant offset of 26 from the peak overpressure expressed in dB gives a good estimate of the CSEL of a sonic boom.

  7. Controlling the sonic boom from a thin body by means of local heating of the incoming flow

    NASA Astrophysics Data System (ADS)

    Potapkin, A. V.; Moskvichev, D. Yu.

    2013-11-01

    The problem of reduction of the sonic boom level by heating the flow in front of the body is solved numerically. A combined method of “phantom bodies” is used for calculations. The sonic boom generated by an axisymmetric thin body for the flight Mach number of 2 with different levels of energy supply to the incoming flow is calculated. The calculation results show that the sonic boom can be reduced by means of local heat supply to a supersonic gas flow. Reduction of the sonic boom level is provided by specific gas-dynamic features of the flow behind the heat supply zone.

  8. Efficient Unstructured Grid Adaptation Methods for Sonic Boom Prediction

    NASA Technical Reports Server (NTRS)

    Campbell, Richard L.; Carter, Melissa B.; Deere, Karen A.; Waithe, Kenrick A.

    2008-01-01

    This paper examines the use of two grid adaptation methods to improve the accuracy of the near-to-mid field pressure signature prediction of supersonic aircraft computed using the USM3D unstructured grid flow solver. The first method (ADV) is an interactive adaptation process that uses grid movement rather than enrichment to more accurately resolve the expansion and compression waves. The second method (SSGRID) uses an a priori adaptation approach to stretch and shear the original unstructured grid to align the grid with the pressure waves and reduce the cell count required to achieve an accurate signature prediction at a given distance from the vehicle. Both methods initially create negative volume cells that are repaired in a module in the ADV code. While both approaches provide significant improvements in the near field signature (< 3 body lengths) relative to a baseline grid without increasing the number of grid points, only the SSGRID approach allows the details of the signature to be accurately computed at mid-field distances (3-10 body lengths) for direct use with mid-field-to-ground boom propagation codes.

  9. Airborne Shaped Sonic Boom Demonstration Pressure Measurements with Computational Fluid Dynamics Comparisons

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.; Murray, James E.; Purifoy, Dana D.; Graham, David H.; Meredith, Keith B.; Ashburn, Christopher E.; Stucky, Mark

    2005-01-01

    The Shaped Sonic Boom Demonstration project showed for the first time that by careful design of aircraft contour the resultant sonic boom can maintain a tailored shape, propagating through a real atmosphere down to ground level. In order to assess the propagation characteristics of the shaped sonic boom and to validate computational fluid dynamics codes, airborne measurements were taken of the pressure signatures in the near field by probing with an instrumented F-15B aircraft, and in the far field by overflying an instrumented L-23 sailplane. This paper describes each aircraft and their instrumentation systems, the airdata calibration, analysis of the near- and far-field airborne data, and shows the good to excellent agreement between computational fluid dynamics solutions and flight data. The flights of the Shaped Sonic Boom Demonstration aircraft occurred in two phases. Instrumentation problems were encountered during the first phase, and corrections and improvements were made to the instrumentation system for the second phase, which are documented in the paper. Piloting technique and observations are also given. These airborne measurements of the Shaped Sonic Boom Demonstration aircraft are a unique and important database that will be used to validate design tools for a new generation of quiet supersonic aircraft.

  10. Ground-based sensors for the SR-71 sonic boom propagation experiment

    NASA Technical Reports Server (NTRS)

    Norris, Stephen R.; Haering, Edward A., Jr.; Murray, James E.

    1995-01-01

    This paper describes ground-level measurements of sonic boom signatures made as part of the SR-71 sonic boom propagation experiment recently completed at NASA Dryden Flight Research Center, Edwards, California. Ground level measurements were the final stage of this experiment which also included airborne measurements at near and intermediate distances from an SR-71 research aircraft. Three types of sensors were deployed to three station locations near the aircraft ground track. Pressure data were collected for flight conditions from Mach 1.25 to Mach 1.60 at altitudes from 30,000 to 48,000 ft. Ground-level measurement techniques, comparisons of data sets from different ground sensors, and sensor system strengths and weaknesses are discussed. The well-known N-wave structure dominated the sonic boom signatures generated by the SR-71 aircraft at most of these conditions. Variations in boom shape caused by atmospheric turbulence, focusing effects, or both were observed for several flights. Peak pressure and boom event duration showed some dependence on aircraft gross weight. The sonic boom signatures collected in this experiment are being compiled in a data base for distribution in support of the High Speed Research Program.

  11. Long-term effects of simulated sonic booms on hearing in rhesus monkeys

    NASA Astrophysics Data System (ADS)

    Reinis, S.; Weiss, D. S.; Featherstone, J. W.; Tsaros, C.

    1987-03-01

    Two monkeys of the species Macaca mulatta were exposed at 1 min intervals to five simulated sonic booms lasting 200 ms at 200 Pa overpressure with a 10 ms rise time. Another group of five monkeys of the same species were exposed to 100 booms. Their hearing thresholds were tested 24 hours, two weeks, one month, two months, four months and six months later. In one animal exposed to five booms, changes of the hearing thresholds were observed 24 hours following the exposure, but not later. All five animals exposed to 100 sonic booms had threshold shifts in the high-frequency range 24 hours following the exposure. Of the three animals followed for the full period of six months, one recovered completely. In the two others, threshold shifts were still observed in the high frequency range. Histological examination revealed destruction of the organ of Corti in the basal turn of the cochlea. These data indicate that there is individual variability in the extent of the damage to the inner ear by the sonic boom (and, perhaps, by other types of impulsive noise). These data also indicate that there is a possibility of similar damage to human inner ears exposed either to sonic booms or to other types of impulsive noise, and that it may go undetected for a long time because the high-frequency hearing defect, over 8 kHz, may be overlooked when routine audiometric methods are used.

  12. 1995 NASA High-Speed Research Program Sonic Boom Workshop. Volume 2; Configuration Design, Analysis, and Testing

    NASA Technical Reports Server (NTRS)

    Baize, Daniel G. (Editor)

    1999-01-01

    The High-Speed Research Program and NASA Langley Research Center sponsored the NASA High-Speed Research Program Sonic Boom Workshop on September 12-13, 1995. The workshop was designed to bring together NASAs scientists and engineers and their counterparts in industry, other Government agencies, and academia working together in the sonic boom element of NASAs High-Speed Research Program. Specific objectives of this workshop were to: (1) report the progress and status of research in sonic boom propagation, acceptability, and design; (2) promote and disseminate this technology within the appropriate technical communities; (3) help promote synergy among the scientists working in the Program; and (4) identify technology pacing, the development C, of viable reduced-boom High-Speed Civil Transport concepts. The Workshop was organized in four sessions: Sessions 1 Sonic Boom Propagation (Theoretical); Session 2 Sonic Boom Propagation (Experimental); Session 3 Acceptability Studies-Human and Animal; and Session 4 - Configuration Design, Analysis, and Testing.

  13. Theoretical Basis for Finite Difference Extrapolation of Sonic Boom Signatures

    NASA Technical Reports Server (NTRS)

    Plotkin, Kenneth J.

    1996-01-01

    Calculation of sonic boom signatures for aircraft has traditionally followed the methods of Whitham' and Walkden. The wave disturbance generated by the vehicle is obtained by area rule linearized supersonic flow methods, which yield a locally axisymmetric asymptotic solution. This solution is acoustic in nature, i.e., first order in disturbance quantities, and corresponds to ray acoustics. Cumulative nonlinear distortion of the signature is incorporated by using this solution to adjust propagation speed to first order, thus yielding a solution second order in disturbance quantities. The effects of atmospheric gradients are treated by Blokhintzov's method of geometrical acoustics. Both nonlinear signature evolution and ray tracing are applied as if the pressure field very close to the vehicle were actually that given by the source term (the 'F-function') of the asymptotic linearized flow solution. The viewpoint is thus that the flow solution exists at a small radius near the vehicle, and may be treated as an input to an extrapolation procedure consisting of ray tracing and nonlinear aging. The F-function is often regarded as a representation of a near-field pressure signature, and it is common for computational implementations to treat it interchangeably with the pressure signature. There is a 'matching radius' between the source function and the subsequent propagation extrapolation. This viewpoint has been supported by wind tunnel tests of simple models, and very typically yields correct results for actual flight vehicles. The assumption that the F-function and near-field signature are interchangeable is generally not correct. The flowfield of a vehicle which is not axisymmetric contains crossflow components which are very significant at small radii and less so at larger distances. From an acoustical viewpoint, the crossflow is equivalent to source diffraction portions of the wave field. Use of the F-function as a near field signature effectively assumes that the

  14. Application of sonic-boom minimization concepts in supersonic transport design

    NASA Technical Reports Server (NTRS)

    Carlson, H. W.; Barger, R. L.; Mack, R. J.

    1973-01-01

    The applicability of sonic boom minimization concepts in the design of large supersonic transport airplanes capable of a 2500-nautical-mile range at a cruise Mach number of 2.7 is considered. Aerodynamics, weight and balance, and mission performance as well as sonic boom factors, have been taken into account. The results indicate that shock-strength nominal values of somewhat less than 48 newtons/sq m during cruise are within the realm of possibility. Because many of the design features are in direct contradiction to presently accepted design practices, further study of qualified airplane design teams is required to ascertain sonic boom shock strength levels actually attainable for practical supersonic transports.

  15. Seismo-acoustic effects of sonic booms on archeological sites, Valentine Military Operations Area

    NASA Astrophysics Data System (ADS)

    Battis, J. C.

    1983-11-01

    Seismo-acoustic recordings of sonic booms were made at two sites in the Valentine Military Operations Areas (MOA). Each location was selected as representative of a class of significant archeological sites found within the MOA. These studies indicate that sonic booms are unlikely to cause damage to the archeological finds. The expected motions are, at worst, 8 percent of the limits set by strict blasting codes and comparable to velocities that could be produced by local earthquakes which have occurred in the Valentine area. At these levels of motion, competent rock will be unaffected by the transmission of seismic waves. The predicted velocity levels are unlikely to initiate either fracture or spalling in rocks. However, it is possible that in rocks where natural meteorological action has initiated these erosive mechanisms the sonic boom induced motion accelerate the processes to some small, and probably insignificant, degree.

  16. Effectiveness of a Wedge Probe to Measure Sonic Boom Signatures in a Supersonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Wilcox, Floyd J., Jr.; Elmiligui, Alaa A.

    2013-01-01

    A wind tunnel investigation was conducted in the Langley Unitary Plan Wind Tunnel (UPWT) to determine the effectiveness of a wedge probe to measure sonic boom pressure signatures compared to a slender conical probe. A generic business jet model at a constant angle of attack and at a single model to probe separation distance was used to generate a sonic boom signature. Pressure signature data were acquired with both the wedge probe and a slender conical probe for comparison. The test was conducted at a Mach number of 2.0 and a free-stream unit Reynolds number of 2 million per foot. The results showed that the wedge probe was not effective in measuring the sonic boom pressure signature of the aircraft model in the supersonic wind tunnel. Data plots and a discussion of the results are presented. No tabulated data or flow visualization photographs are included.

  17. Pilot Test of a Novel Method for Assessing Community Response to Low-Amplitude Sonic Booms

    NASA Technical Reports Server (NTRS)

    Fidell, Sanford; Horonjeff, Richard D.; Harris, Michael

    2012-01-01

    A pilot test of a novel method for assessing residents annoyance to sonic booms was performed. During a two-week period, residents of the base housing area at Edwards Air Force Base provided data on their reactions to sonic booms using Smartphone-based interviews. Noise measurements were conducted at the same time. The report presents information about data collection methods and about test participants reactions to low-amplitude sonic booms. The latter information should not be viewed as definitive for several reasons. It may not be reliably generalized to the wider U.S. residential population (because it was not derived from a representative random sample) and the sample itself was not large.

  18. Effect of the supersonic transport configuration on the sonic boom parameters

    NASA Astrophysics Data System (ADS)

    Fomin, V. M.; Chirkashenko, V. F.; Volkov, V. F.; Kharitonov, A. M.

    2011-12-01

    Results of numerical and experimental investigations of the sonic boom parameters for two configurations of civil supersonic transport are presented. Numerical modelling is performed by a combined method based on calculating the spatial flow in the near zone of the aircraft configuration and subsequent determination of disturbed flow parameters at large distances from the examined model. Numerical results are compared with experimental sonic boom parameters measured in the near zone and with results of their recalculation to large distances within the framework of the quasi-linear theory. This validation allows the degree of adequacy of the inviscid Euler model for solving the posed problem to be determined. Reasons for certain disagreement between the calculated and experimental data are discussed. The analysis confirms the possibility of attenuating the sonic boom generated by supersonic transport with an unconventional configuration based on a tandem arrangement of two wings on the fuselage.

  19. Design methodology for a community response questionnaire on sonic boom exposure

    NASA Technical Reports Server (NTRS)

    Farbry, John E., Jr.; Fields, James M.; Molino, John A.; Demiranda, Gwendolyn A.

    1991-01-01

    A preliminary draft questionnaire concerning community response to sonic booms was developed. Interviews were conducted in two communities that had experienced supersonic overflights of the SR-71 airplane for several years. Even though the overflights had ceased about 6 months prior to the interviews, people clearly remembered hearing sonic booms. A total of 22 people living in central Utah and 23 people living along Idaho/Washington state border took part in these interviews. The draft questionnaire was constantly modified during the study in order to evaluate different versions. Questions were developed which related to annoyance, startle, sleep disturbance, building vibration, and building damage. Based on the data collected, a proposed community response survey response instrument was developed for application in a full-scale sonic boom study.

  20. High-Speed Research: 1994 Sonic Boom Workshop: Atmospheric Propagation and Acceptability Studies

    NASA Technical Reports Server (NTRS)

    Mccurdy, David A. (Editor)

    1994-01-01

    The workshop proceedings include papers on atmospheric propagation and acceptability studies. Papers discussing atmospheric effects on the sonic boom waveform addressed several issues. It has long been assumed that the effects of molecular relaxation are adequately accounted for by assuming that a steady state balance between absorption and nonlinear wave steepening exists. It was shown that the unsteadiness induced by the nonuniform atmosphere precludes attaining this steady state. Further, it was shown that the random atmosphere acts as a filter, effectively filtering out high frequency components of the distorted waveform. Several different propagation models were compared, and an analysis of the sonic boom at the edge of the primary carpet established that the levels there are bounded. Finally, a discussion of the levels of the sonic boom below the sea surface was presented.

  1. Design methodology for a community response questionnaire on sonic boom exposure

    NASA Astrophysics Data System (ADS)

    Farbry, John E., Jr.; Fields, James M.; Molino, John A.; Demiranda, Gwendolyn A.

    1991-05-01

    A preliminary draft questionnaire concerning community response to sonic booms was developed. Interviews were conducted in two communities that had experienced supersonic overflights of the SR-71 airplane for several years. Even though the overflights had ceased about 6 months prior to the interviews, people clearly remembered hearing sonic booms. A total of 22 people living in central Utah and 23 people living along Idaho/Washington state border took part in these interviews. The draft questionnaire was constantly modified during the study in order to evaluate different versions. Questions were developed which related to annoyance, startle, sleep disturbance, building vibration, and building damage. Based on the data collected, a proposed community response survey response instrument was developed for application in a full-scale sonic boom study.

  2. Nacelle Integration to Reduce the Sonic Boom of Aircraft Designed to Cruise at Supersonic Speeds

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    1999-01-01

    An empirical method for integrating the engine nacelles on a wing-fuselage-fin(s) configuration has been described. This method is based on Whitham theory and Seebass and George sonic-boom minimization theory, With it, both reduced sonic-boom as well as high aerodynamic efficiency methods can be applied to the conceptual design of a supersonic-cruise aircraft. Two high-speed civil transport concepts were used as examples to illustrate the application of this engine-nacelle integration methodology: (1) a concept with engine nacelles mounted on the aft-fuselage, the HSCT-1OB; and (2) a concept with engine nacelles mounted under an extended-wing center section, the HSCT-11E. In both cases, the key to a significant reduction in the sonic-boom contribution from the engine nacelles was to use the F-function shape of the concept as a guide to move the nacelles further aft on the configuration.

  3. A laboratory study of subjective response to sonic booms measured at White Sands Missile Range

    NASA Technical Reports Server (NTRS)

    Sullivan, Brenda M.; Leatherwood, Jack D.

    1993-01-01

    The Sonic Boom Simulator of the Langley Research Center was used to quantify subjective loudness response to boom signatures consisting of: (1) simulator reproductions of booms recently recorded at White Sands Missile Range; (2) idealized N-waves; and (3) idealized booms having intermediate shocks. The booms with intermediate shocks represented signatures derived from CFD predictions. The recorded booms represented those generated by F15 and T38 aircraft flyovers and represented a variety of waveforms reflecting the effects of propagation through a turbulent atmosphere. These waveforms included the following shape categories: N-waves, peaked, rounded, and U-shaped. Results showed that Perceived Level and Zwicker Loudness Level were good estimators of the loudness of turbulence modified sonic booms. No significant differences were observed between loudness responses for the several shape categories when expressed in terms of Perceived Level. Thus, Perceived Level effectively accounted for waveform differences due to turbulence. Idealized booms with intermediate shocks, however, were rated as being approximately 2.7 dB(PL) less loud than the recorded signatures. This difference was not accounted for by PL.

  4. Analysis of Plume Effects on Sonic Boom Signature for Isolated Nozzle Configurations

    NASA Technical Reports Server (NTRS)

    Castner, Raymond S.

    2008-01-01

    Computational fluid dynamics (CFD) analysis has been performed to study the plume effects on sonic boom signature for isolated nozzle configurations. The objectives of these analyses were to provide comparison to past work using modern CFD analysis tools, to investigate the differences of high aspect ratio nozzles to circular (axisymmetric) nozzles, and to report the effects of underexpanded nozzle operation on boom signature. CFD analysis was used to address the plume effects on sonic boom signature from a baseline exhaust nozzle. Near-field pressure signatures were collected for nozzle pressure ratios (NPRs) between 6 and 10. A computer code was used to extrapolate these signatures to a ground-observed sonic boom N-wave. Trends show that there is a reduction in sonic boom N-wave signature as NPR is increased from 6 to 10. The performance curve for this supersonic nozzle is flat, so there is not a significant loss in thrust coefficient as the NPR is increased. As a result, this benefit could be realized without significant loss of performance. Analyses were also collected for a high aspect ratio nozzle based on the baseline design for comparison. Pressure signatures were collected for nozzle pressure ratios from 8 to 12. Signatures were nearly twice as strong for the two-dimensional case, and trends also show a reduction in sonic boom signature as NPR is increased from 8 to 12. As low boom designs are developed and improved, there will be a need for understanding the interaction between the aircraft boat tail shocks and the exhaust nozzle plume. These CFD analyses will provide a baseline study for future analysis efforts.

  5. The effect of aircraft speed on the penetration of sonic boom noise into a flat ocean

    NASA Technical Reports Server (NTRS)

    Sparrow, Victor W.

    1994-01-01

    As U.S. aircraft manufacturers now have focused their HSCT efforts on overwater supersonic flight, a great deal more must be known about sonic booms propagating overwater and interacting with the ocean. For example, it is thought that atmospheric turbulence effects are often much less severe over water than over land. Another important aspect of the overwater flight problems is the penetration of the sonic boom noise into the ocean, where there could be an environmental impact on sea life. This talk will present a brief review on the penetration of sonic boom noise into a large body of water with a flat surface. It has been determined recently that faster supersonic speeds imply greater penetration of sonic boom noise into the ocean. The new theory is derived from the original Sawyers paper and from the knowledge that for level flight a boom's duration is proportional to the quantity M/(M(exp 2)-1)(exp 3/8) where M is the Mach number. It is found that for depths of 10 m or less, the peak SPL varies less than 6 dB over a wide range of M. For greater depths, 100 m for example, increased Mach numbers may increase the SPL by 15 dB or more.

  6. Minimizing the transient vibroacoustic response of a window to sonic booms by using stiffeners.

    PubMed

    Ou, Dayi; Ming Mak, Cheuk

    2014-04-01

    A stiffened-window strategy is proposed for reducing the window's transient responses to sonic booms. Additional movable and controllable stiffeners are used, which can improve the window's transient vibration and noise isolation performance without significantly reducing transparency. A simple prediction model is proposed as a design tool for implementing the stiffened-window structure, which allows for the computation of a plate with arbitrary elastic boundary conditions and arbitrarily located stiffeners. The predicted results agree well with experimental data. Also, the feasibility and validity of the stiffened-window strategy for improving the window's performance in response to sonic booms is demonstrated by parametric studies. PMID:25234966

  7. Charts for determining potential minimum sonic-boom overpressures for supersonic cruise aircraft

    NASA Technical Reports Server (NTRS)

    Darden, C. M.

    1981-01-01

    Charts which give an estimation of minimum achievable sonic-boom levels for supersonic cruise aircraft are presented. A minimization method based on modified linear theory was analyzed. Results show several combinations of Mach number, altitude, and aircraft length and weight. Overpressure and impulse values are given for two types of sonic boom signatures for each of these conditions: (1) a flat top or minimum overpressure signature which has a pressure plateau behind the initial shock, and (2) a minimum shock signature which allows a pressure rise after the initial shock. Results are given for the effects of nose shape.

  8. Effects of lengthwise lift distribution on sonic boom of SST configurations

    NASA Technical Reports Server (NTRS)

    Ferri, A.; Ismail, A.

    1977-01-01

    Sonic Boom signatures produced by possible SST configurations during cruise were investigated. It is shown that optimization based on a far field analysis is not necessarily the optimum for these conditions. For an airplane length of 300 ft, near-field effects can be obtained when sufficient lift is generated near the nose of the airplane. Because of the near-field effects, sonic booms with maximum overpressures of the order of 1 lb/square foot can be obtained with possible airplane configurations having the same flight conditions at cruise.

  9. Modification of sonic boom wave forms during propagation from the source to the ground.

    PubMed

    Bass, Henry E; Raspet, Richard; Chambers, James P; Kelly, Mark

    2002-01-01

    A number of physical processes work to modify the shape of sonic boom wave forms as the wave form propagates from the aircraft to a receiver on the ground. These include frequency-dependent absorption, nonlinear steepening, and scattering by atmospheric turbulence. In the past two decades, each of these effects has been introduced into numerical prediction algorithms and results compared to experimental measurements. There is still some disagreement between measurements and prediction, but those differences are now in the range of tens of percent. The processes seem to be understood. The present understanding of sonic boom evolution will be presented along with experimental justification. PMID:11837953

  10. Method for Estimating the Sonic-Boom Characteristics of Lifting Canard-Wing Aircraft Concepts

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    2005-01-01

    A method for estimating the sonic-boom overpressures from a conceptual aircraft where the lift is carried by both a canard and a wing during supersonic cruise is presented and discussed. Computer codes used for the prediction of the aerodynamic performance of the wing, the canard-wing interference, the nacelle-wing interference, and the sonic-boom overpressures are identified and discussed as the procedures in the method are discussed. A canard-wing supersonic-cruise concept was used as an example to demonstrate the application of the method.

  11. Simplified sonic-boom prediction. [using aerodynamic configuration charts and calculators or slide rules

    NASA Technical Reports Server (NTRS)

    Carlson, H. W.

    1978-01-01

    Sonic boom overpressures and signature duration may be predicted for the entire affected ground area for a wide variety of supersonic airplane configurations and spacecraft operating at altitudes up to 76 km in level flight or in moderate climbing or descending flight paths. The outlined procedure relies to a great extent on the use of charts to provide generation and propagation factors for use in relatively simple expressions for signature calculation. Computational requirements can be met by hand-held scientific calculators, or even by slide rules. A variety of correlations of predicted and measured sonic-boom data for airplanes and spacecraft serve to demonstrate the applicability of the simplified method.

  12. In-Flight Technique for Acquiring Mid- And Far-Field Sonic Boom Signatures

    NASA Technical Reports Server (NTRS)

    Stansbery, Eugene G.; Baize, Daniel G.; Maglieri, Domenic, J.

    1999-01-01

    Flight test experiments have been conducted to establish the feasibility of obtaining sonic boom signature measurements below a supersonic aircraft using the NASA Portable Automatic Triggering System (PATS) mounted in the USMC Pioneer Unmanned Aerial Vehicle (UAV). This study forms a part of the NASA sonic boom minimization activities, specifically the demonstration of persistence of modified boom signatures to very large distances in a real atmosphere. The basic objective of the measurement effort was to obtain a qualitative view of the sonic boom signature in terms of its shape, number of shocks, their locations, and their relative strength. Results suggest that the technique may very well provide quantitative information relative to mid-field and far-field boom signatures. The purpose of this presentation is to describe the arrangement and operation of this in-flight system and to present the resulting sonic boom measurements. Adaption and modification of two PATS to the UAV payload section are described and include transducer location, mounting arrangement and recording system isolation. Ground static runup, takeoff and landing, and cruise flight checkouts regarding UAV propeller and flow noise on the PATS automated triggering system and recording mode are discussed. For the proof-of-concept tests, the PATS instrumented UAV was flown under radar control in steady-level flight at the altitude of 8700 feet MSL and at a cruise speed of about 60 knots. The USN F-4N sonic boom generating aircraft was vectored over the UAV on reciprocal headings at altitudes of about 1 1,000 feet MSL and 13,000 feet MSL at about Mach 1. 15. Sonic boom signatures were acquired on both PATS for all six supersonic passes. Although the UAV propeller noise is clearly evident in all the measurements, the F-4 boom signature is clearly distinguishable and is typically N-wave in character with sharply rising shock fronts and with a mid-shock associated with the inlet-wing juncture

  13. Low sonic boom design and performance of a Mach 2.4/1.8 overland high speed civil transport

    NASA Technical Reports Server (NTRS)

    Morgenstern, John M.

    1992-01-01

    This paper describes the design features of a Douglas Mach 2.4/1.8 Low Sonic Boom High Speed Civil Transport (HSCT) configuration developed for NASA. The configuration is designed to fly over water at Mach 2.4 for highest productivity and economic worth, and fly over land at Mach 1.8 with reduced sonic boom loudness.

  14. An investigation into the effect of playback environment on perception of sonic booms when heard indoors

    NASA Astrophysics Data System (ADS)

    Carr, Daniel; Davies, Patricia

    2015-10-01

    Aircraft manufacturers are interested in designing and building a new generation of supersonic aircraft that produce shaped sonic booms of lower peak amplitude than booms created by current supersonic aircraft. To determine if the noise exposure from these "low"booms is more acceptable to communities, new laboratory testing to evaluate people's responses must occur. To guide supersonic aircraft design, objective measures that predict human response to modified sonic boom waveforms and other impulsive sounds are needed. The present research phase is focused on understanding people's reactions to booms when heard inside, and therefore includes consideration of the effects of house type and the indoor acoustic environment. A test was conducted in NASA Langley's Interior Effects Room (IER), with the collaboration of NASA Langley engineers. This test was focused on the effects of low-frequency content and of vibration, and subjects sat in a small living room environment. A second test was conducted in a sound booth at Purdue University, using similar sounds played back over earphones. The sounds in this test contained less very-low-frequency energy due to limitations in the playback, and the laboratory setting is a less natural environment. For the purpose of comparison, and to improve the robustness of the model, both sonic booms and other more familiar transient sounds were used in the tests. The design of the tests and the signals are briefly described, and the results of both tests will be presented.

  15. High-Speed Research: 1994 Sonic Boom Workshop. Configuration, Design, Analysis and Testing

    NASA Technical Reports Server (NTRS)

    McCurdy, David A. (Editor)

    1999-01-01

    The third High-Speed Research Sonic Boom Workshop was held at NASA Langley Research Center on June 1-3, 1994. The purpose of this workshop was to provide a forum for Government, industry, and university participants to present and discuss progress in their research. The workshop was organized into sessions dealing with atmospheric propagation; acceptability studies; and configuration design, and testing. Attendance at the workshop was by invitation only. The workshop proceedings include papers on design, analysis, and testing of low-boom high-speed civil transport configurations and experimental techniques for measuring sonic booms. Significant progress is noted in these areas in the time since the previous workshop a year earlier. The papers include preliminary results of sonic boom wind tunnel tests conducted during 1993 and 1994 on several low-boom designs. Results of a mission performance analysis of all low-boom designs are also included. Two experimental methods for measuring near-field signatures of airplanes in flight are reported.

  16. Noise and sonic-boom impact technology. PCBOOM computer program for sonic-boom research. Volume 1. Technical report. Final report, May 1987-October 1988

    SciTech Connect

    Bishop, D.E.

    1988-10-01

    The PCBOOM computer program, described in this technical report, calculates the location and magnitude of sonic-boom overpressures on the ground due to supersonic flight under standard atmosphere and no wind-propagation conditions. The program is intended for environmental planners and engineers who may need to estimate the noise impact from individual flights of supersonic military aircraft. The program runs on a Zenith Z-248 personal computer and also should run on most similarly configured IBM-compatible computers. The program contains information for all current military aircraft and allows updating for additional aircraft. The user can select either 'Quick look' computations which assume steady-state flight or detailed ray-tracing calculations which can handle non-steady flight and sonic-boom focus conditions. Several types of simple maneuvers can be selected for computations; the program will also handle up to ten connected straight-line segments. Flight segments from the MOAOPS library of supersonic combat training flights may also be selected. User-specified output for printer, plotter or screen includes tables of overpressures and graphic display of the sonic-boom overpressure 'footprints' on the ground. The footprint plots show the location of all ray positions that exceed overpressures of a given level. Flight track, Mach number, and altitude profile plots are also provided. This report summarizes the technical basis for PCBOOM. Two other reports provide a program users/computer operations manual and a program maintenance manual.

  17. Effect of sonic boom on avalanches. Preparation for flight of a supersonic jet over the Lavay Valley

    NASA Technical Reports Server (NTRS)

    Schaffar, M.; Carrie, B.; Amardeil, P.

    1986-01-01

    An experiment to determine the effect of sonic booms on the stability of the snow mantle in the Lavey Valley is proposed. It includes provisions for the aircraft trajectory, line of fucus, boom zone, as well as the determination of boom intensity levels for the whole valley.

  18. Using FUN3D for Aeroelastic, Sonic Boom, and AeroPropulsoServoElastic (APSE) Analyses of a Supersonic Configuration

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.; Sanetrik, Mark D.; Chwalowski, Pawel; Connolly, Joseph; Kopasakis, George

    2016-01-01

    An overview of recent applications of the FUN3D CFD code to computational aeroelastic, sonic boom, and aeropropulsoservoelasticity (APSE) analyses of a low-boom supersonic configuration is presented. The overview includes details of the computational models developed including multiple unstructured CFD grids suitable for aeroelastic and sonic boom analyses. In addition, aeroelastic Reduced-Order Models (ROMs) are generated and used to rapidly compute the aeroelastic response and utter boundaries at multiple flight conditions.

  19. Design of Experiments for Both Experimental and Analytical Study of Exhaust Plume Effects on Sonic Boom

    NASA Technical Reports Server (NTRS)

    Castner, Raymond S.

    2009-01-01

    Computational fluid dynamics (CFD) analysis has been performed to study the plume effects on sonic boom signature for isolated nozzle configurations. The objectives of these analyses were to provide comparison to past work using modern CFD analysis tools, to investigate the differences of high aspect ratio nozzles to circular (axisymmetric) nozzles, and to report the effects of under expanded nozzle operation on boom signature. CFD analysis was used to address the plume effects on sonic boom signature from a baseline exhaust nozzle. Nearfield pressure signatures were collected for nozzle pressure ratios (NPRs) between 6 and 10. A computer code was used to extrapolate these signatures to a ground-observed sonic boom N-wave. Trends show that there is a reduction in sonic boom N-wave signature as NPR is increased from 6 to 10. As low boom designs are developed and improved, there will be a need for understanding the interaction between the aircraft boat tail shocks and the exhaust nozzle plume. These CFD analyses will provide a baseline study for future analysis efforts. For further study, a design of experiments has been conducted to develop a hybrid method where both CFD and small scale wind tunnel testing will validate the observed trends. The CFD and testing will be used to screen a number of factors which are important to low boom propulsion integration, including boat tail angle, nozzle geometry, and the effect of spacing and stagger on nozzle pairs. To design the wind tunnel experiment, CFD was instrumental in developing a model which would provide adequate space to observe the nozzle and boat tail shock structure without interference from the wind tunnel walls.

  20. Significance of the Atmosphere and Aircraft Operations on Sonic-Boom Exposures

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Hilton, David A.

    1965-01-01

    The information of the paper is in the form of a status report on the state of knowledge of sonic-boom phenomena, dealing first with the pressure buildups in the transonic speed range and with the lateral extent of the pattern in steady flight for quiescent atmospheric conditions. There are also discussions of recent data from flight-test studies relating to atmospheric dynamic effects on the sonic-boom signatures, and finally, brief discussions of the significance of signature shape on the response of people and structures. The acceleration and lateral-spread phenomena appear to be fairly well understood and predictable for current and future aircraft. Variations in the sonic-boom signature as a result of the effects of the atmosphere can be expected during routine operations. From the data evaluated to date, very similar variations in pressure signatures are noted for both fighter and bomber aircraft. The greatest questions still exist in the area of community acceptance of sonic booms. A more definitive answer to the community-acceptance problem will have to await adequate flight experience with larger aircraft.

  1. Uncertainty Analysis of Sonic Boom Levels Measured in a Simulator at NASA Langley

    NASA Technical Reports Server (NTRS)

    Rathsam, Jonathan; Ely, Jeffry W.

    2012-01-01

    A sonic boom simulator has been constructed at NASA Langley Research Center for testing the human response to sonic booms heard indoors. Like all measured quantities, sonic boom levels in the simulator are subject to systematic and random errors. To quantify these errors, and their net influence on the measurement result, a formal uncertainty analysis is conducted. Knowledge of the measurement uncertainty, or range of values attributable to the quantity being measured, enables reliable comparisons among measurements at different locations in the simulator as well as comparisons with field data or laboratory data from other simulators. The analysis reported here accounts for acoustic excitation from two sets of loudspeakers: one loudspeaker set at the facility exterior that reproduces the exterior sonic boom waveform and a second set of interior loudspeakers for reproducing indoor rattle sounds. The analysis also addresses the effect of pressure fluctuations generated when exterior doors of the building housing the simulator are opened. An uncertainty budget is assembled to document each uncertainty component, its sensitivity coefficient, and the combined standard uncertainty. The latter quantity will be reported alongside measurement results in future research reports to indicate data reliability.

  2. Experimental Measurements of Sonic Boom Signatures Using a Continuous Data Acquisition Technique

    NASA Technical Reports Server (NTRS)

    Wilcox, Floyd J.; Elmiligui, Alaa A.

    2013-01-01

    A wind tunnel investigation was conducted in the Langley Unitary Plan Wind Tunnel to determine the effectiveness of a technique to measure aircraft sonic boom signatures using a single conical survey probe while continuously moving the model past the probe. Sonic boom signatures were obtained using both move-pause and continuous data acquisition methods for comparison. The test was conducted using a generic business jet model at a constant angle of attack and a single model-to-survey-probe separation distance. The sonic boom signatures were obtained at a Mach number of 2.0 and a unit Reynolds number of 2 million per foot. The test results showed that it is possible to obtain sonic boom signatures while continuously moving the model and that the time required to acquire the signature is at least 10 times faster than the move-pause method. Data plots are presented with a discussion of the results. No tabulated data or flow visualization photographs are included.

  3. Effects of aircraft noise and sonic booms on domestic animals and wildlife: a literature synthesis

    SciTech Connect

    Manci, K.M.; Gladwin, D.N.; Villella, R.; Cavendish, M.G.

    1988-06-01

    An information base on the effects of aircraft noise and sonic booms on various animal species is necessary to assess potential impacts to wildlife populations from proposed military flight operations. Thus, in a joint U.S. Air Force/U.S. Fish and Wildlife Service effort, the National Ecology Research Center conducted a literature search of information pertaining to animal hearing and the effects of aircraft noise and sonic booms on domestic animals and wildlife. Information concerning other types of noise was also gathered to supplement the lack of knowledge on the effects of aircraft noise. The literature is summarized in the report to provide an overview of current knowledge. No attempt was made to evaluate the appropriateness or adequacy or the scientific approach of each study. A brief overview of the physics of sound and aircraft noise and sonic-boom characteristics also is included to familiarize the reader with the terminology and concepts of aircraft noise and sonic-boom impact analysis.

  4. Simulator Study of Indoor Annoyance Caused by Shaped Sonic Boom Stimuli With and Without Rattle Augmentation

    NASA Technical Reports Server (NTRS)

    Rathsam, Jonathan; Loubeau, Alexandra; Klos, Jacob

    2013-01-01

    The National Aeronautics and Space Administration's High Speed Project is developing a predictive capability for annoyance caused by shaped sonic booms transmitted indoors. The predictive capability is intended for use by aircraft designers as well as by aircraft noise regulators who are considering lifting the current prohibition on overland civil supersonic flight. The goal of the current study is to use an indoor simulator to validate two models developed using headphone tests for annoyance caused by sonic booms with and without rattle augmentation. The predictors in the proposed models include Moore and Glasberg's Stationary Loudness Level, the time derivative of Moore and Glasberg's time-varying short-term Loudness Level, and the difference between two weighted sound exposure levels, CSEL-ASEL. The indoor simulator provides a more realistic listening environment than headphones due to lowfrequency sound reproduction down to 6 Hz, which also causes perceptible tactile vibration. The results of this study show that a model consisting of {PL + (CSEL-ASEL)} is a reliable predictor of annoyance caused by shaped sonic booms alone, rattle sounds alone, and shaped sonic booms and rattle sounds together.

  5. Ground-recorded sonic boom signatures of F-18 aircraft formation flight

    NASA Technical Reports Server (NTRS)

    Bahm, Catherine M.; Haering, Edward A., Jr.

    1995-01-01

    Two F-18 aircraft were flown, one above the other, in two formations, in order for the shock systems of the two aircraft to merge and propagate to the ground. The first formation had the canopy of the lower F-18 in the inlet shock of the upper F-18 (called inlet-canopy). The flight conditions were Mach 1.22 and an altitude of 23,500 ft. An array of five sonic boom recorders was used on the ground to record the sonic boom signatures. This paper describes the flight test technique and the ground level sonic boom signatures. The tail-canopy formation resulted in two, separated, N-wave signatures. Such signatures probably resulted from aircraft positioning error. The inlet-canopy formation yielded a single modified signature; two recorders measured an approximate flattop signature. Loudness calculations indicated that the single inlet-canopy signatures were quieter than the two, separated tail-canopy signatures. Significant loudness occurs after a sonic boom signature. Such loudness probably comes from the aircraft engines.

  6. Ground-Recorded Sonic Boom Signatures of F-18 Aircraft in Formation Flight

    NASA Technical Reports Server (NTRS)

    Bahm, Catherine M.; Haering, Edward A., Jr.

    1996-01-01

    Two F-18 aircraft were flown, one above the other, in two formations, in order for the shock systems of the two aircraft to merge and propagate to the ground. The first formation had the canopy of the lower F-18 in the tail shock of the upper F-18 (called tail-canopy). The second formation had the canopy of the lower F- 18 in the inlet shock of the upper F-18 (called inlet-canopy). The flight conditions were Mach 1.22 and an altitude of 23,500 ft . An array of five sonic boom recorders was used on the ground to record the sonic boom signatures. This paper describes the flight test technique and the ground level sonic boom signatures. The tail-canopy formation resulted in two, separated, N-wave signatures. Such signatures probably resulted from aircraft positioning error. The inlet-canopy formation yielded a single modified signature; two recorders measured an approximate flattop signature. Loudness calculations indicated that the single inlet-canopy signatures were quieter than the two, separated tail-canopy signatures. Significant loudness occurs after a sonic boom signature. Such loudness probably comes from the aircraft engines.

  7. Prediction of sonic boom from experimental near-field overpressure data. Volume 2: Data base construction

    NASA Technical Reports Server (NTRS)

    Glatt, C. R.; Reiners, S. J.; Hague, D. S.

    1975-01-01

    A computerized method for storing, updating and augmenting experimentally determined overpressure signatures has been developed. A data base of pressure signatures for a shuttle type vehicle has been stored. The data base has been used for the prediction of sonic boom with the program described in Volume I.

  8. A new evaluation of noise metrics for sonic booms using existing data

    NASA Astrophysics Data System (ADS)

    Loubeau, Alexandra; Naka, Yusuke; Cook, Brian G.; Sparrow, Victor W.; Morgenstern, John M.

    2015-10-01

    An evaluation of noise metrics for predicting human perception of sonic booms was performed. Twenty-five metrics were chosen from standards and from the literature in an effort to include all potentially relevant metrics. Three different datasets of sonic boom waveforms and associated human response were chosen to span a variety of signals, including traditional N-waves with various shock shapes and rise times, and predicted waveforms from designs of low-boom aircraft for a variety of aircraft sizes. These datasets were derived from laboratory studies conducted in sonic boom simulators at NASA Langley Research Center and JAXA. Simulations of booms experienced in both outdoor and indoor environments were included by using different facilities at NASA or modifications to facility configurations at JAXA. American and Japanese test subjects participated at NASA and JAXA, respectively. Ratings of loudness using a magnitude estimation technique and ratings of annoyance using a category line scaling method are included. The evaluation consists of linear correlations of human response data with the objective noise metrics. Results are presented for each study, and eight metrics are suggested for further analysis.

  9. CFD Predictions of Sonic-Boom Characteristics for Unmodified and Modified SR-71 Configurations

    NASA Technical Reports Server (NTRS)

    Fouladi, Kamran

    1999-01-01

    Shaped sonic-boom signatures refer to signatures that look something other than the typical N-waves. Shaped sonic-boom signatures such as "flat-top," "ramp-type," or "hybrid-type" waveforms have been shown to reduce the subjective loudness without requiring reductions in overpressure peaks. The shaping of sonic-boom signatures requires increasing the shock rise time and changes in frequency spectra. So far, a flat-top waveform was shown to be achievable in wind tunnels; however, the influence of long propagation distance and real atmosphere on shaped signatures should be addressed using flight tests. Two different approaches have been proposed for sonic-boom minimization flight tests. The first approach, proposed by Eagle Aerospace, is for a flight test using a modified BQM-34 "FIREBEE" remotely piloted vehicle. The 30-foot long FIREBEE has a steady state flight condition at the Mach number and altitude of interest, and it can be recovered by helicopter from the water. As an alternative approach, a modified SR-71 vehicle has been proposed by the McDonnell Douglas Corporation. Benefits of the SR-71 include its variable geometry supersonic inlets, small cockpit bulge, higher Mach number capabilities, slender design, and longer length (105 foot). The present investigation addresses the sonic-boom analysis for the second vehicle.The objective of the current investigation is to assess the feasibility of a modified SR-71 configuration, with McDonnell Douglas-designed fuselage modifications, intended to produce shaped sonic-boom signatures on the ground. The present study describes the use of a higher-order computational fluid dynamics (CFD) method to predict the sonic-boom characteristics for both unmodified and modified SR-71 configurations. An Euler unstructured grid methodology is used to predict the near-field, three-dimensional pressure patterns generated by both SR-71 models. The computed near-field pressure signatures are extrapolated to specified distances below

  10. Supersonic airplane design optimization method for aerodynamic performance and low sonic boom

    NASA Technical Reports Server (NTRS)

    Cheung, Samson H.; Edwards, Thomas A.

    1992-01-01

    This paper presents a new methodology for the optimization of supersonic airplane designs to meet the dual design objectives of low sonic boom and high aerodynamic performance. Two sets of design parameters are used on an existing High Speed Civil Transport (HSCT) configuration to maximize the aerodynamic performance and minimize the sonic boom under the flight track. One set of the parameters perturbs the camber line of the wing sections to maximize the lift-over-drag ratio (L/D). A preliminary optimization run yielded a 3.75 percent improvement in L/D over a baseline low-boom configuration. The other set of parameters modifies the fuselage area to achieve a target F-function. Starting from an initial configuration with strong bow, wing, and tail shocks, a modified design with a flat-top signature is obtained. The methods presented can easily incorporate other design variables and objective functions. Extensions to the present capability in progress are described.

  11. Human Response to Low-Intensity Sonic Booms Heard Indoors and Outdoors

    NASA Technical Reports Server (NTRS)

    Sullivan, Brenda M.; Klos, Jacob; Buehrle, Ralph D.; McCurdy, David A.; Haering, Edward A., Jr.

    2010-01-01

    Test subjects seated inside and outside a house were exposed to low-intensity N-wave sonic booms during a 3-week test period in June 2006- The house was instrumented to measure the booms both inside and out. F-18 aircraft were flown to achieve a variety of boom overpressures from approximately .1 to .6 psf During four test days, seventy-seven test subjects heard the booms while seated inside and outside the house. Using the Magnitude Estimation methodology and artificial reference sounds ; the subjects rated the annoyance of the booms. Since the same subjects heard similar booms both inside and outside the house, comparative ratings of indoor and outdoor annoyance were obtained. For a given metric level, indoor subjects gave higher annoyance scores than outdoor subjects. For a given boom; annoyance scores inside were on average the same as those outside. In a post-test questionnaire, the majority of subjects rated the indoor booms as more annoying than the outdoor ones. These results are discussed in this paper.

  12. Raptor responses to low-level jet aircraft and sonic booms.

    PubMed

    Ellis, D H; Ellis, C H; Mindell, D P

    1991-01-01

    We estimated effects of low-level military jet aircraft and mid- to high-altitude sonic booms (actual and simulated) on nesting peregrine falcons (Falco peregrinus) and seven other raptors by observing their responses to test stimuli, determining nesting success for the test year, and evaluating site reoccupancy rates for the year following the tests. Frequent and nearby jet aircraft passes: (1) sometimes noticeably alarmed birds, (2) occasionally caused birds to fly from perches or eyries, (3) most often evoked only minimal responses, and (4) were never associated with reproductive failure. Similarly, responses to real and simulated mid- to high-altitude sonic booms were often minimal and never appeared productivity limiting. Eighteen (95%) of 19 nest sites subjected to low-level jet flights and/or simulated sonic booms in 1980 fledged young during that year. Eighteen (95%) of 19 sites disturbed in 1980 were reoccupied by pairs or lone birds of the same species in 1981. We subjected four pairs of prairie falcons (Falco mexicanus) to low-level aircraft at ad libitum levels during the courtship and incubation phases when adults were most likely to abandon: all four eyries fledged young. From heart rate (HR) data taken via a telemetering egg at another prairie falcon eyrie, we determined that stimulus-induced HR alterations were comparable to rate changes for birds settling to incubate following flight. While encouraging, our findings cannot be taken as conclusive evidence that jet flights and/or sonic booms will have no long-term negative effects for other raptor species or for other areas. In addition, we did not experiment with totally naive wild adults, rotary-winged aircraft, or low-level sonic booms. PMID:15092075

  13. Raptor responses to low-level jet aircraft and sonic booms

    USGS Publications Warehouse

    Ellis, D.H.; Ellis, C.H.; Mindell, D.P.

    1991-01-01

    We estimated effects of low-level military jet aircraft and mid- to high-altitude sonic booms (actual and simulated) on nesting peregrine falcons (Falco peregrinus) and seven other raptors by observing their responses to test stimuli, determining nesting success for the test year, and evaluating site reoccupancy rates for the year following the tests. Frequent and nearby jet aircraft passes: (1) sometimes noticeably alarmed birds, (2) occasionally caused birds toffy from perches or eyries, (3) most often evoked only minimal responses, and (4) were never associated with reproductive failure. Similarly, responses to real and simulated mid- to high-altitude sonic booms were often minimal and never appeared productivity limiting. Eighteen (95%) of 19 nest sites subjected to low-level jet flights and/or simulated sonic booms in 1980 fledged young during that year. Eighteen (95%) of l9 sites disturbed in 1980 were reoccupied by pairs or lone birds of the same species in 1981. We subjected four pairs of prairie falcons (Falco mexicanus) to low-level aircraft at ad libitum levels during the courtship and incubation phases when adults were most likely to abandon: all four eyries fledged young. From heart rate (HR) data taken via a telemetering egg at another prairie falcon eyrie, we determined that stimulus-induced HR alterations were comparable to rate changes for birds settling to incubate following flight. While encouraging, our findings cannot be taken as conclusive evidence that jet flights and/or sonic booms will have no long-term negative effects for other raptor species or for other areas. In addition, we did not experiment with totally naive wild adults, rotary-winged aircraft, or low-level sonic booms.

  14. A laboratory study of subjective annoyance response to sonic booms and aircraft flyovers

    NASA Astrophysics Data System (ADS)

    Leatherwood, Jack D.; Sullivan, Brenda M.

    1994-05-01

    Three experiments were conducted to determine subjective equivalence of aircraft subsonic flyover noise and sonic booms. Two of the experiments were conducted in a loudspeaker-driven sonic boom simulator, and the third in a large room containing conventional loudspeakers. The sound generation system of the boom simulator had a frequency response extending to very low frequencies (about 1 Hz) whereas the large room loudspeakers were limited to about 20 Hz. Subjective equivalence between booms and flyovers was quantified in terms of the difference between the noise level of a boom and that of a flyover when the two were judged equally annoying. Noise levels were quantified in terms of the following noise descriptors: Perceived Level (PL), Perceived Noise Level (PNL), C-weighted sound exposure level (SELC), and A-weighted sound exposure level (SELA). Results from the present study were compared, where possible, to similar results obtained in other studies. Results showed that noise level differences depended upon the descriptor used, specific boom and aircraft noise events being compared and, except for the PNL descriptor, varied between the simulator and large room. Comparison of noise level differences obtained in the present study with those of other studies indicated good agreement across studies only for the PNL and SELA descriptors. Comparison of the present results with assessments of community response to high-energy impulsive sounds made by Working Group 84 of the National Research Council's Committee on Hearing, Bioacoustics, and Biomechanics (CHABA) showed good agreement when boom/flyover noise level differences were based on SELA. However, noise level differences obtained by CHABA using SELA for aircraft flyovers and SELC for booms were not in agreement with results obtained in the present study.

  15. A laboratory study of subjective annoyance response to sonic booms and aircraft flyovers

    NASA Technical Reports Server (NTRS)

    Leatherwood, Jack D.; Sullivan, Brenda M.

    1994-01-01

    Three experiments were conducted to determine subjective equivalence of aircraft subsonic flyover noise and sonic booms. Two of the experiments were conducted in a loudspeaker-driven sonic boom simulator, and the third in a large room containing conventional loudspeakers. The sound generation system of the boom simulator had a frequency response extending to very low frequencies (about 1 Hz) whereas the large room loudspeakers were limited to about 20 Hz. Subjective equivalence between booms and flyovers was quantified in terms of the difference between the noise level of a boom and that of a flyover when the two were judged equally annoying. Noise levels were quantified in terms of the following noise descriptors: Perceived Level (PL), Perceived Noise Level (PNL), C-weighted sound exposure level (SELC), and A-weighted sound exposure level (SELA). Results from the present study were compared, where possible, to similar results obtained in other studies. Results showed that noise level differences depended upon the descriptor used, specific boom and aircraft noise events being compared and, except for the PNL descriptor, varied between the simulator and large room. Comparison of noise level differences obtained in the present study with those of other studies indicated good agreement across studies only for the PNL and SELA descriptors. Comparison of the present results with assessments of community response to high-energy impulsive sounds made by Working Group 84 of the National Research Council's Committee on Hearing, Bioacoustics, and Biomechanics (CHABA) showed good agreement when boom/flyover noise level differences were based on SELA. However, noise level differences obtained by CHABA using SELA for aircraft flyovers and SELC for booms were not in agreement with results obtained in the present study.

  16. Measured Effects of Turbulence on the Loudness and Waveforms of Conventional and Shaped Minimized Sonic Booms

    NASA Technical Reports Server (NTRS)

    Plotkin, Kenneth J.; Maglieri, Domenic J.; Sullivan, Brenda M.

    2005-01-01

    Turbulence has two distinctive effects on sonic booms: there is distortion in the form of random perturbations that appear behind the shock waves, and shock rise times are increased randomly. A first scattering theory by S.C. Crow in the late 1960s quantified the random distortions, and Crow's theory was shown to agree with available flight test data. A variety of theories for the shock thickness have been presented, all supporting the role of turbulence in increasing rise time above that of a basic molecular-relaxation structure. The net effect of these phenomena on the loudness of shaped minimized booms is of significant interest. Initial analysis suggests that there would be no change to average loudness, but this had not been experimentally investigated. The January 2004 flight test of the Shaped Sonic Boom Demonstrator (SSBD), together with a reference unmodified F-5E, included a 12500- foot linear ground sensor array with 28 digitally recorded sensor sites. This data set provides an opportunity to re-test Crow's theory for the post-shock perturbations, and to examine the net effect of turbulence on the loudness of shaped sonic booms.

  17. Solution of the lossy nonlinear Tricomi equation with application to sonic boom focusing

    NASA Astrophysics Data System (ADS)

    Salamone, Joseph A., III

    Sonic boom focusing theory has been augmented with new terms that account for mean flow effects in the direction of propagation and also for atmospheric absorption/dispersion due to molecular relaxation due to oxygen and nitrogen. The newly derived model equation was numerically implemented using a computer code. The computer code was numerically validated using a spectral solution for nonlinear propagation of a sinusoid through a lossy homogeneous medium. An additional numerical check was performed to verify the linear diffraction component of the code calculations. The computer code was experimentally validated using measured sonic boom focusing data from the NASA sponsored Superboom Caustic and Analysis Measurement Program (SCAMP) flight test. The computer code was in good agreement with both the numerical and experimental validation. The newly developed code was applied to examine the focusing of a NASA low-boom demonstration vehicle concept. The resulting pressure field was calculated for several supersonic climb profiles. The shaping efforts designed into the signatures were still somewhat evident despite the effects of sonic boom focusing.

  18. Summary of the 2008 NASA Fundamental Aeronautics Program Sonic Boom Prediction Workshop

    NASA Technical Reports Server (NTRS)

    Park, Michael A.; Aftosmis, Michael J.; Campbell, Richard L.; Carter, Melissa B.; Cliff, Susan; Nangert, Linda S.

    2013-01-01

    The Supersonics Project of the NASA Fundamental Aeronautics Program organized an internal sonic boom workshop to evaluate near- and mid-field sonic boom prediction capability at the Fundamental Aeronautics Annual Meeting in Atlanta, Georgia on October 8, 2008. Workshop participants computed sonic boom signatures for three non-lifting bodies and two lifting configurations. A cone-cylinder, parabolic, and quartic bodies of revolution comprised the non-lifting cases. The lifting configurations were a simple 69-degree delta wing body and a complete low-boom transport configuration designed during the High Speed Research Project in the 1990s with wing, body, tail, nacelle, and boundary layer diverter components. The AIRPLANE, Cart3D, FUN3D, and USM3D ow solvers were employed with the ANET signature propagation tool, output-based adaptation, and a priori adaptation based on freestream Mach number and angle of attack. Results were presented orally at the workshop. This article documents the workshop, results, and provides context on previously available and recently developed methods.

  19. Numerical simulation of shock wave focusing at fold caustics, with application to sonic boom.

    PubMed

    Marchiano, Régis; Coulouvrat, François; Grenon, Richard

    2003-10-01

    Weak shock wave focusing at fold caustics is described by the mixed type elliptic/hyperbolic nonlinear Tricomi equation. This paper presents a new and original numerical method for solving this equation, using a potential formulation and an "exact" numerical solver for handling nonlinearities. Validation tests demonstrate quantitatively the efficiency of the algorithm, which is able to handle complex waveforms as may come out from "optimized" aircraft designed to minimize sonic booms. It provides a real alternative to the approximate method of the hodograph transform. This motivated the application to evaluate the ground track focusing of sonic boom for an accelerating aircraft, by coupling CFD Euler simulations performed around the mock-up on an adaptated mesh grid, atmospheric propagation modeling, and the Tricomi algorithm. The chosen configuration is the European Eurosup mock-up. Convergence of the focused boom at the ground level as a function of the matching distance is investigated to demonstrate the efficiency of the numerical process. As a conclusion, it is indicated how the present work may pave the way towards a study on sonic superboom (focused boom) mitigation. PMID:14587578

  20. Vibroacoustic Response of Residential Housing due to Sonic Boom Exposure: A Summary of two Field Tests

    NASA Technical Reports Server (NTRS)

    Klos, Jacob; Buehrle, Ralph; Sullivan, Brenda; Gavin, Joseph; Salamone, Joseph; Haering, Edward A., jr.; Miller, Denise M.

    2008-01-01

    Two experiments have been performed to measure the vibroacoustic response of houses exposed to sonic booms. In 2006, an old home in the base housing area of Edwards Air Force Base, built around 1960 and demolished in 2007, was instrumented with 288 transducers. During a 2007 follow-on test, a newer home in the base housing area, built in 1997, was instrumented with 112 transducers. For each experiment, accelerometers were placed on walls, windows and ceilings in bedrooms of the house to measure the vibration response of the structure. Microphones were placed outside and inside the house to measure the excitation field and resulting interior sound field. The vibroacoustic response of each house was measured for sonic boom amplitudes spanning from 2.4 to 96 Pa (0.05 to 2 lbf/sq ft). The boom amplitudes were systematically varied using a unique dive maneuver of an F/A-18 airplane. In total, the database for both houses contains vibroacoustic response data for 154 sonic booms. In addition, several tests were performed with mechanical shaker excitation of the structure to characterize the forced response of the houses. The purpose of this paper is to summarize all the data from these experiments that are available to the research community, and to compare and contrast the vibroacoustic behavior of these two dissimilar houses.

  1. Laboratory study of effects of sonic boom shaping on subjective loudness and acceptability

    NASA Technical Reports Server (NTRS)

    Leatherwood, Jack D.; Sullivan, Brenda M.

    1992-01-01

    A laboratory study was conducted to determine the effects of sonic boom signature shaping on subjective loudness and acceptability. The study utilized the sonic boom simulator at the Langley Research Center. A wide range of symmetrical, front-shock-minimized signature shapes were investigated together with a limited number of asymmetrical signatures. Subjective loudness judgments were obtained from 60 test subjects by using an 11-point numerical category scale. Acceptability judgments were obtained using the method of constant stimuli. Results were used to assess the relative predictive ability of several noise metrics, determine the loudness benefits of detailed boom shaping, and derive laboratory sonic boom acceptability criteria. These results indicated that the A-weighted sound exposure level, the Stevens Mark 7 Perceived Level, and the Zwicker Loudness Level metrics all performed well. Significant reductions in loudness were obtained by increasing front-shock rise time and/or decreasing front-shock overpressure of the front-shock minimized signatures. In addition, the asymmetrical signatures were rated to be slightly quieter than the symmetrical front-shock-minimized signatures of equal A-weighted sound exposure level. However, this result was based on a limited number of asymmetric signatures. The comparison of laboratory acceptability results with acceptability data obtained in more realistic situations also indicated good agreement.

  2. Theoretical and Computational Studies on Sonic Boom Propagation and Its Submarine Impact

    NASA Technical Reports Server (NTRS)

    Cheng, H. K.; Lee, C. J.; Hafez, M. M.; Guo, W. H.

    1996-01-01

    Sonic boom impact on the environment of populated area and habitat has been a major concern for the design, operation, and program planning of super/hypersonic vehicles as well as sE launch. Recent development in sonic boom studies reviewed has made evident need for amending the near-field analysis with nonlinear calculations, but an unambiguous matching procedure to assure waveform-prediction improvement is still lacking. Another problem receiving much attention recently is the renewed issue with 'transition focus booms' particularly the 'superboom' which occurs during a speed change through a threshold Mach number and gives rise to strong wave-focussing effects; however, its intensity and the extent of the impact area not be established from existing methods. A third aspect of a more recent concern is the potential sonic boom impact on pelagic and coastal environment, of which the methodology for defining impact has yet to be adequately developed. The study addresses these three aspects in the frame work of a wave-field analysis for a stratified atmosphere, employing coordinates fixed to the vehicle in steady horizontal motion.

  3. Slot Nozzle Effects for Reduced Sonic Boom on a Generic Supersonic Wing Section

    NASA Technical Reports Server (NTRS)

    Castner, Raymond S.

    2010-01-01

    NASA has conducted research programs to reduce or eliminate the operational restrictions of supersonic aircraft over populated areas. Restrictions are due to the disturbance from the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Results from two-dimensional computational fluid dynamic (CFD) analyses (performed on a baseline Mach 2.0 nozzle in a simulated Mach 2.2 flow) indicate that over-expanded and under-expanded operation of the nozzle has an effect on the N-wave boom signature. Analyses demonstrate the feasibility of reducing the magnitude of the sonic boom N-wave by controlling the nozzle plume interaction with the nozzle boat tail shock structure. This work was extended to study the impact of integrating a high aspect ratio exhaust nozzle or long slot nozzle on the trailing edge of a supersonic wing. The nozzle is operated in a highly under-expanded condition, creating a large exhaust plume and a shock at the trailing edge of the wing. This shock interacts with and suppresses the expansion wave caused by the wing, a major contributor to the sonic boom signature. The goal was to reduce the near field pressures caused by the expansion using a slot nozzle located at the wing trailing edge. Results from CFD analysis on a simulated wing cross-section and a slot nozzle indicate potential reductions in sonic boom signature compared to a baseline wing with no propulsion or trailing edge exhaust. Future studies could investigate if this effect could be useful on a supersonic aircraft for main propulsion, auxiliary propulsion, or flow control.

  4. [Sonic booms--new environmental factor (bases for standardization)].

    PubMed

    Iuganov, E M; Krylov, Iu V; Kuznetsov, V S

    1976-01-01

    The paper discusses physical, psychophysiological and social aspects of a new type of sound effects--sonic shocks of supersonic vehicles. An up-to-date approach to the standardization of environmental effects should include a study of human physiological responses, comparison of the results of psychophysiological scaling with the available standards and prediction based on sociological questionnaires. This kind of standardization is illustrated. PMID:979115

  5. Human response to house vibrations caused by sonic booms or air blasts.

    PubMed

    Schomer, P D

    1978-07-01

    Descriptions of the effects of sonic booms of air blasts by observers in buildings have included such statements as "noticeable vibrations" in addition to phrases such as "the house rattles," "the windows rattle," or "bric-à-brac rattles." Analysis of studies of human response to vibrations, vibration complaints in the Toronto area, special tests by Kryter at Edwards Air Force Base, and laboratory studies of human response to sonic booms show that perceived vibration is not normally a factor that contributes significantly to human response to airborne, large-amplitude impulse noise. Rather, human response is solely the result of the impulse noise itself and of audible noise due to induced radiation from vibrating surfaces. PMID:711997

  6. Effects of aircraft noise and sonic booms on domestic animals and wildlife: bibliographic abstracts

    SciTech Connect

    Gladwin, D.N.; Manci, K.M.; Villella, R.

    1988-06-01

    The purpose of the document is to provide an information base on the effects of aircraft noise and sonic booms on various animal species. Such information is necessary to assess potential impacts to wildlife populations from proposed military and other flight operations. To develop the document the National Ecology Research Center conducted a literature search of information pertaining to animal hearing and the effects of aircraft noise and sonic booms on domestic animals and wildlife. Information concerning other types of noise was also gathered to supplement the lack of knowledge on the effects of aircraft noise. The bibliographic abstracts in the report provide a compilation of current knowledge. No attempt was made to evaluate the appropriateness or adequacy of the scientific approach of each study. (A literature synthesis is available in a separate document.)

  7. Development and evaluation of a device to simulate a sonic boom

    NASA Technical Reports Server (NTRS)

    Rash, L. C.; Barrett, R. F.; Hart, F. D.

    1972-01-01

    A device to simulate the vibrational and acoustical properties of a sonic boom was developed and evaluated. The design employed a moving circular diaphragm which produced pressure variations by altering the volume of an air-tight enclosure that was located adjacent to an acoustical test chamber. A review of construction oriented problems, along with their solutions, is presented. The simulator is shown to produce the effects of sonic booms having pressure signatures with rise times as low as 5 milliseconds, durations as short as 80 milliseconds, and overpressures as high as 2.5 pounds per square foot. Variations in the signatures are possible by independent adjustments of the simulator. The energy spectral density is also shown to be in agreement with theory and with actual measurements for aircraft.

  8. A solid state converter for measurement of aircraft noise and sonic boom

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.

    1972-01-01

    The problems inherent in present systems of instrumentation for measuring aircraft noise and sonic boom include limited frequency response, expensive connecting cables, sensitivity to cable length and type, high sensitivity to environmental conditions, and additional limitations of individual system components. Furthermore, differing requirements have resulted in the use of two different systems for aircraft noise and sonic boom measurements respectively. To alleviate these difficulties a unified system of instrumentation suitable for both types of measurements was developed. The system features a new solid state converter connected to a zero drive amplifier. The system was found insensitive to cable length and type up to at least 1000 ft and requires no impedance matching networks. The converter itself has flat frequency response from dc to 28 kHz (- 3 db), dynamic range of 72 db, and noise floor of 50 db in the band 22.4 Hz to 22.4 kHz.

  9. Reduction of the sonic boom level in supersonic aircraft flight by the method of surface cooling

    NASA Astrophysics Data System (ADS)

    Fomin, V. M.; Chirkashenko, V. F.; Volkov, V. F.; Kharitonov, A. M.

    2013-12-01

    Based on the analysis of various aspects of creating a supersonic transport aircraft of the second generation, the necessity of developing unconventional active methods of sonic boom level reduction is demonstrated. Surface cooling is shown to exert a significant effect on formation of the disturbed flow structure up to large distances from the body by an example of a supersonic flow around a body of revolution. A method of reducing the intensity of the intermediate shock wave and excess pressure momentum near the body is proposed. This method allows the length of the reduced (by 50%) sonic boom level to be increased and the bow shock wave intensity in the far zone to be reduced by 12%. A possibility of controlling the process of formation of wave structures, such as hanging pressure shocks arising near the aircraft surface, is demonstrated. The action of the cryogenic mechanism is explained.

  10. Reduction of the sonic boom level in supersonic aircraft flight by the method of surface cooling

    NASA Astrophysics Data System (ADS)

    Fomin, V. M.; Chirkashenko, V. F.; Volkov, V. F.; Kharitonov, A. M.

    2014-12-01

    Based on the analysis of various aspects of creating a supersonic transport aircraft of the second generation, the necessity of developing unconventional active methods of sonic boom level reduction is demonstrated. Surface cooling is shown to exert a significant effect on formation of the disturbed flow structure up to large distances from the body by an example of a supersonic flow around a body of revolution. A method of reducing the intensity of the intermediate shock wave and excess pressure momentum near the body is proposed. This method allows the length of the reduced (by 50%) sonic boom level to be increased and the bow shock wave intensity in the far zone to be reduced by 12%. A possibility of controlling the process of formation of wave structures, such as hanging pressure shocks arising near the aircraft surface, is demonstrated. The action of the cryogenic mechanism is explained.

  11. Minimization of sonic-boom parameters in real and isothermal atmospheres. [overpressure and acoustic impedance

    NASA Technical Reports Server (NTRS)

    Darden, C. M.

    1975-01-01

    The procedure for sonic-boom minimization introduced by Seebass and George for an isothermal atmosphere was converted for use in the real atmosphere by means of the appropriate equations for sonic-boom pressure signature advance, ray-tube area, and acoustic impedance. Results of calculations using both atmospheres indicate that except for low Mach numbers or high altitudes, the isothermal atmosphere with a scale height of 7620 m (25 000 ft) gives a reasonable estimate of the values of overpressure, impulse, and characteristic overpressure obtained by using the real atmosphere. The results also show that for aircraft design studies, propagation of a known F-function, or minimization studies at low supersonic Mach numbers, the isothermal approximation is not adequate.

  12. A study to determine the feasibility of a low sonic boom supersonic transport

    NASA Technical Reports Server (NTRS)

    Kane, E. J.

    1973-01-01

    A study was made to determine the feasibility of supersonic transport configurations designed to produce a goal sonic boom signature with low overpressure. The results indicate that, in principle, such a concept represents a potentially realistic design approach assuming technology of the 1985 time period. Two sonic boom goals were selected which included: (1) A high speed design that would produce shock waves no stronger than 48 Newtons per square meter (1.0 psf); and an intermediate Mach number (mid-Mach) design that would produce shock waves no stronger than 24 Newtons per square meter. The high speed airplane design was a Mach 2.7 blended arrow wing configuration which was capable of carrying 183 passengers a distance of 7000 km (3780 nmi) while meeting the signature goal. The mid-Mach airplane designed was a Mach 1.5 low arrow wing configuration with a horizontal tail which could carry 180 passengers a distance of 5960 km (3220 nmi).

  13. Computational/experimental analysis of three low sonic boom configurations with design modifications

    NASA Technical Reports Server (NTRS)

    Cliff, Susan E.

    1992-01-01

    The Euler code, designated AIRPLANE, which uses an unstructured tetrahedral mesh was used to compute near-field sonic boom pressure signatures on three modern low sonic boom configurations: the Mach 2, Mach 3, and Haglund models. The TEAM code which uses a multi-zoned structured grid was used to calculate pressure signatures for the Mach 2 model. The computational pressure signatures for the Mach 2 and Mach 3 models are compared with recent experimental data. The computed pressure signatures were extracted at distances less than one body length below the configuration and extrapolated to the experimental distance. The Mach 2 model was found to have larger overpressures off-ground-track than on-ground-track in both computational and experimental results. The correlations with the experiment were acceptable where the signatures were not contaminated by instrumentation and model-support hardware. AIRPLANE was used to study selected modifications to improve the overpressures of the Mach 2 model.

  14. Sonic boom results for a nominal mission 3B. Space Shuttle engineering and operations support, engineering systems analysis

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The results obtained in the analysis of the effects of sonic boom overpressures at ground level for a nominal Mission 3B with the current baseline guidance are reported. These results are in the form of ground level overpressures generated along the groundtrack out to lateral cutoff from Mach 3.0-1.10 at 0.10 (tenth) Mach intervals. Preliminary trajectory constraints which will reduce excess sonic boom overpressures to approximately 2.0 PSF are included.

  15. Atmospheric turbulence conditions leading to focused and folded sonic boom wave fronts.

    PubMed

    Piacsek, Andrew A

    2002-01-01

    The propagation and subsequent distortion of sonic booms with rippled wave fronts are investigated theoretically using a nonlinear time-domain finite-difference scheme. This work seeks to validate the rippled wave front approach as a method for explaining the significant effects of turbulence on sonic booms [A. S. Pierce and D. J. Maglieri, J. Acoust. Soc. Am. 51, 702-721 (1971)]. A very simple description of turbulence is employed in which velocity perturbations within a shallow layer of the atmosphere form strings of vortices characterized by their size and speed. Passage of a steady-state plane shock front through such a vortex layer produces a periodically rippled wave front which, for the purposes of the present investigation, serves as the initial condition for a finite-difference propagation scheme. Results show that shock strength and ripple curvature determine whether ensuing propagation leads to wave front folding. High resolution images of the computed full wave field provide insights into the spiked and rounded features seen in sonic booms that have propagated through turbulence. PMID:11837957

  16. Analysis of Exhaust Plume Effects on Sonic Boom for a 59-Degree Wing Body Model

    NASA Technical Reports Server (NTRS)

    Castner, Raymond S.

    2011-01-01

    Reducing or eliminating the operational restrictions of supersonic aircraft over populated areas has led to extensive research at NASA. Restrictions are due to the disturbance of the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Recent work has been performed to reduce the magnitude of the sonic boom N-wave generated by airplane components with focus on shock waves caused by the exhaust nozzle plume. Previous Computational Fluid Dynamics (CFD) analyses showed how the shock wave formed at the nozzle lip interacted with the nozzle boat-tail expansion wave. The nozzle lip shock moved with increasing nozzle pressure ratio (NPR) and reduced the nozzle boat-tail expansion. Lip shock movement caused a favorable change in the observed pressure signature. These results were applied to a simplified supersonic vehicle geometry with no inlets and no tail, in which the goal was to demonstrate how under-expanded nozzle operation reduced the sonic boom signature by twelve percent. A secondary goal was to demonstrate the use of the Cart3D inviscid code for off-body pressure signatures including the nozzle plume effect.

  17. Reduction of the sonic boom level by heating the flow in front of the body

    NASA Astrophysics Data System (ADS)

    Potapkin, A. V.; Moskvichev, D. Yu.

    2014-07-01

    A numerical study of the possibility of reducing the sonic boom level in the case of local heat release to a supersonic gas flow at Mach number equal to 2 ahead of a body is described. The computations are performed for a spherical heat supply zone located on the flight trajectory ahead of the tip of an axisymmetric thin body. For the numerical study the combined method of "phantom bodies" is used. Different magnitudes of heat supply to the incoming flow are tested. These calculations are performed with allowance for interaction of shock waves emanating from the heated gas region and from the body in the far field. The computational results show that the local heat supply to a supersonic gas flow ahead of a body can reduce the sonic boom level by more than 20 %. The reduction of the sonic boom level is ensured by changing the free-stream parameters ahead of the body and by preventing the coalescence of shock waves from the heat supply zone and from the body in the far field.

  18. Exhaust Nozzle Plume Effects on Sonic Boom Test Results for Vectored Nozzles

    NASA Technical Reports Server (NTRS)

    Castner, Raymond

    2012-01-01

    Reducing or eliminating the operational restrictions of supersonic aircraft over populated areas has led to extensive research at NASA. Restrictions were due to the disturbance of the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Recent work has been performed to reduce the magnitude of the sonic boom N-wave generated by airplane components with a focus on shock waves caused by the exhaust nozzle plume. Previous Computational Fluid Dynamics (CFD) analysis showed how the shock wave formed at the nozzle lip interacts with the nozzle boat-tail expansion wave. An experiment was conducted in the 1- by 1-foot Supersonic Wind Tunnel (SWT) at the NASA Glenn Research Center. Results show how the shock generated at the nozzle lip affects the near field pressure signature, and thereby the potential sonic boom contribution for a nozzle at vector angles from 3 to 8 . The experiment was based on the NASA F-15 nozzle used in the Lift and Nozzle Change Effects on Tail Shock experiment, which possessed a large external boat-tail angle. In this case, the large boat-tail angle caused a dramatic expansion, which dominated the near field pressure signature. The impact of nozzle vector angle and nozzle pressure ratio are summarized.

  19. Handling Qualities Prediction of an F-16XL-Based Reduced Sonic Boom Aircraft

    NASA Technical Reports Server (NTRS)

    Cogan, Bruce; Yoo, Seung

    2010-01-01

    A major goal of the Supersonics Project under NASA s Fundamental Aeronautics program is sonic boom reduction of supersonic aircraft. An important part of this effort is development and validation of sonic boom prediction tools used in aircraft design. NASA Dryden s F- 16XL was selected as a potential testbed aircraft to provide flight validation. Part of this task was predicting the handling qualities of the modified aircraft. Due to the high cost of modifying the existing F-16XL control laws, it was desirable to find modifications that reduced the aircraft sonic boom but did not degrade baseline aircraft handling qualities allowing for the potential of flight test without changing the current control laws. This was not a requirement for the initial modification design work, but an important consideration for proceeding to the flight test option. The primary objective of this work was to determine an aerodynamic and mass properties envelope of the F-16XL aircraft. The designers could use this envelope to determine the effect of proposed modifications on aircraft handling qualities.

  20. Sonic-boom ground pressure measurements from the launch and reentry of Apollo 16

    NASA Technical Reports Server (NTRS)

    Henderson, H. R.; Hilton, D. A.

    1974-01-01

    Sonic-boom pressure signatures recorded during the launch and reentry phases of the Apollo 16 mission are presented. Five measurements were obtained along the vehicle ground track: 69 km (37.3 n. mi.) 92 km (49.8 n. mi.), and 130 km (70.3 n. mi.) down range from the launch site during ascent, and at 185 km (100 n. mi.) and approximately 5.5 km (3 n. mi.) from the splash-down point during reentry. Tracings of the measured signatures are included along with values of the overpressure, impulse, time duration, and rise times. Also included are brief descriptions of the launch and recovery test areas in which the measurements were obtained, the sonic-boom instrumentation deployment, flight profiles, and operating conditions for the launch vehicle and spacecraft, surface weather information at the measuring sites, and high-altitude weather information for the general measurement areas. Comparisons of the sonic-boom overpressures from Apollo 15 and 16 along with those from current aircraft are also presented.

  1. Variability of focused sonic booms from accelerating supersonic aircraft in consideration of meteorological effects

    NASA Astrophysics Data System (ADS)

    Blumrich, Reinhard; Coulouvrat, François; Heimann, Dietrich

    2005-08-01

    Statistics of the meteorologically induced variability of focused sonic boom characteristics due to unsteady, accelerated supersonic flights were derived. The simulations were performed with an advanced sonic boom software including a numerical solver of the Nonlinear Tricomi Equation modeling the focused sound pressure field around caustics. A one-year set of daily meteorological data along the Northern Atlantic flight corridor was used as input. The statistics comprise the location, strength and geometrical extension of caustics at ground level for assumed flights of a supersonic commercial transport from Paris to New York and back. Caustics only occurred during the acceleration phase above the English Channel for flights from Paris to New York, never during the deceleration phase of return flights. The mean value of the maximum focused overpressure is found to be about 4 times the maximum overpressure for cruise flight at Mach 2 in similar conditions, but shows a large variability. The caustics intersection with the ground varies between 3 and 8 km in width and between 30 and 180 km in length. A linear correlation analysis showed the relationship between meteorological profile shape parameters and the focused sonic boom characteristics.

  2. Overview of feasibility study on conducting overflight measurements of shaped sonic boom signatures using RPV's

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Sothcott, Victor E.; Keefer, Thomas N., Jr.; Bobbitt, Percy J.

    1992-01-01

    Before beginning this presentation, it is appropriate to acknowledge the sincere interest and financial support provided by the NASA LaRC under contract NAS9-17900. An outline of the material to be used in the present paper is given. It begins with a indication of the origin and objectives of the feasibility study. This is followed by a discussion of various simulation methods of establishing the persistence of shaped sonic boom signatures to large distances including the use of recoverable RPV/drones. The desirable features to be sought out in an RPV along with a rationale for the selection of a 'shaped' sonic boom signature will be addressed. Three candidate vehicles are examined as to their suitability with respect to a number of factors, in particular, modifiability. Area distributions and associated sonic boom signatures of the basic and modified Firebee vehicle will also be shown. An indication of the scope of the proposed wind tunnel and flight test programs will be presented including measurement technologies and predicted waveforms. Finally, some remarks will be made summarizing the study and highlighting the key findings.

  3. Overview of feasibility study on conducting overflight measurements of shaped sonic boom signatures using RPV's

    NASA Astrophysics Data System (ADS)

    Maglieri, Domenic J.; Sothcott, Victor E.; Keefer, Thomas N., Jr.; Bobbitt, Percy J.

    1992-04-01

    Before beginning this presentation, it is appropriate to acknowledge the sincere interest and financial support provided by the NASA LaRC under contract NAS9-17900. An outline of the material to be used in the present paper is given. It begins with a indication of the origin and objectives of the feasibility study. This is followed by a discussion of various simulation methods of establishing the persistence of shaped sonic boom signatures to large distances including the use of recoverable RPV/drones. The desirable features to be sought out in an RPV along with a rationale for the selection of a 'shaped' sonic boom signature will be addressed. Three candidate vehicles are examined as to their suitability with respect to a number of factors, in particular, modifiability. Area distributions and associated sonic boom signatures of the basic and modified Firebee vehicle will also be shown. An indication of the scope of the proposed wind tunnel and flight test programs will be presented including measurement technologies and predicted waveforms. Finally, some remarks will be made summarizing the study and highlighting the key findings.

  4. Development of a model of startle resulting from exposure to sonic booms

    NASA Astrophysics Data System (ADS)

    Marshall, Andrew J.

    Aircraft manufacturers believe that it is possible to create supersonic business jets that would have quieter sonic booms than those that lead to the current ban on overland commercial supersonic flight over the US. In order to assess if the impact of these "low booms" is acceptable to the public, new human subject testing must occur. In recent studies, it was found that subjects' judgments of annoyance were highly correlated to judgments of startle and were unable to be fully explained by loudness judgments alone. However, this experiment utilized earphones for playback, which was unable to reproduce low frequencies (< 25 Hz) well. Building upon this study, an additional semantic differential experiment was conducted using a sonic boom simulator for playback which could reproduce these frequency components. Results of both experiments were similar and again it was found that average startle and annoyance ratings were highly correlated and that statistics of time-varying loudness were highly correlated with subjects' responses. However, it was unclear if subjects' judgments of startle corresponded to physiological responses associated with startle. To examine if physiological responses associated with startle were evoked by the low booms, two studies were conducted; a pilot study and a repeatability study. While physiological responses associated with startle were evoked by low booms, startle responses were found to have occurred infrequently. However, subjects' judgments of startle were found to be correlated with physiological responses and to have less day-to-day and subject to-subject variance. Candidate startle models were estimated from data obtained from an experiment where subjects' judged the startle evoked by a series of low amplitude sonic booms and boom-like noises. These candidate startle models were then tested in an additional study which used a more diverse set of stimuli. It was found that a linear model consisting of the maximum long-term Moore

  5. A Supersonic Business-Jet Concept Designed for Low Sonic Boom

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    2003-01-01

    Ongoing human-response studies of sonic-boom noise indicated that a previous level of 1.0 psf might still be too annoying. This led to studies of a Supersonic Business Jet (SBJ), which might generate lower, more acceptable ground overpressures. To determine whether methods for designing a High Speed Civil Transport (HSCT) could be successfully applied, a SBJ concept was designed at the langley Research Center. It would cruise at Mach 2, carry 10 passengers for 4000 nautical miles, and generate a 0.50 psf or less on the ground under the flight path at start of cruise. Results indicated that a 10-passenger, low-boom SBJ design was just as technically demanding as a 300-passenger, low-boom HSCT design. In this report, the sources of these technical problems are identified, and ideas for addressing them are discussed.

  6. Impact of multipole matching resolution on supersonic aircraft sonic boom assessment

    NASA Astrophysics Data System (ADS)

    Salah El Din, I.; Le Pape, M.-C.; Minelli, A.; Grenon, R.; Carrier, G.

    2013-06-01

    Sonic boom assessment methods through numerical analysis have been ever-evolving since the development of the fundamental theory. With the growing need for efficient low-boom design tools and the increasing computational resources, original approaches using advanced numerical simulation techniques have been developed. Among the various existing methods, the three-layer resolution introduced in the 1990s is very convenient for low-boom aircraft design. It is based on near-field computational fluid dynamics (CFD) calculation which is matched with the far-field propagation code using a description of the source with multipoles before undergoing classical acoustic propagation through atmosphere. The present paper reviews the theory of the near- to far-field matching as well as the different resolution approaches and their limits. The impact of the resolution method on the ground propagated signal is also presented.

  7. Application of Adjoint Methodology in Various Aspects of Sonic Boom Design

    NASA Technical Reports Server (NTRS)

    Rallabhandi, Sriram K.

    2014-01-01

    One of the advances in computational design has been the development of adjoint methods allowing efficient calculation of sensitivities in gradient-based shape optimization. This paper discusses two new applications of adjoint methodology that have been developed to aid in sonic boom mitigation exercises. In the first, equivalent area targets are generated using adjoint sensitivities of selected boom metrics. These targets may then be used to drive the vehicle shape during optimization. The second application is the computation of adjoint sensitivities of boom metrics on the ground with respect to parameters such as flight conditions, propagation sampling rate, and selected inputs to the propagation algorithms. These sensitivities enable the designer to make more informed selections of flight conditions at which the chosen cost functionals are less sensitive.

  8. Cart3D Analysis of Plume and Shock Interaction Effects on Sonic Boom

    NASA Technical Reports Server (NTRS)

    Castner, Raymond

    2015-01-01

    A plume and shock interaction study was developed to collect data and perform CFD on a configuration where a nozzle plume passed through the shock generated from the wing or tail of a supersonic vehicle. The wing or tail was simulated with a wedge-shaped shock generator. Three configurations were analyzed consisting of two strut mounted wedges and one propulsion pod with an aft deck from a low boom vehicle concept. Research efforts at NASA were intended to enable future supersonic flight over land in the United States. Two of these efforts provided data for regulatory change and enabled design of low boom aircraft. Research has determined that sonic boom is a function of aircraft lift and volume distribution. Through careful tailoring of these variables, the sonic boom of concept vehicles has been reduced. One aspect of vehicle tailoring involved how the aircraft engine exhaust interacted with aft surfaces on a supersonic aircraft, such as the tail and wing trailing edges. In this work, results from Euler CFD simulations are compared to experimental data collected on sub-scale components in a wind tunnel. Three configurations are studied to simulate the nozzle plume interaction with representative wing and tail surfaces. Results demonstrate how the plume and tail shock structure moves with increasing nozzle pressure ratio. The CFD captures the main features of the plume and shock interaction. Differences are observed in the plume and deck shock structure that warrant further research and investigation.

  9. Diffraction of sonic booms around buildings resulting in the building spiking effect.

    PubMed

    Cho, Sang-Ik T; Sparrow, Victor W

    2011-03-01

    The diffraction of a sonic boom around a building of finite dimensions yields amplification of the front shock and a positive spike that follows the tail shock in the pressure waveform recorded at the incident side of the building's exterior surface. This physical phenomenon is consistently found both in the data obtained from a 2006 NASA flight test and field experiment, and in the finite-difference time-domain simulation that models this particular experiment, and the authors call it the "building spiking" effect. This paper presents an analysis of the numerical and the accompanying experimental results used to investigate the cause of this effect. The simulation assumes linear acoustics only, which sufficiently describes the physics of interest. Separating the low and high frequency components of boom recordings using optimal finite impulse response filters with complementary magnitude responses shows that the building spiking effect can be attributed to the frequency dependent nature of diffraction. A comparison of the building spiking effect of a conventional N-wave and a low-amplitude sonic boom shows that a longer shock rise time leads to less pronounced amplification of the exterior pressure loading on buildings, and thus reveals an advantage of shaping a boom to elongate its rise time. PMID:21428488

  10. Sonic Boom Prediction and Minimization of the Douglas Reference OPT5 Configuration

    NASA Technical Reports Server (NTRS)

    Siclari, Michael J.

    1999-01-01

    Conventional CFD methods and grids do not yield adequate resolution of the complex shock flow pattern generated by a real aircraft geometry. As a result, a unique grid topology and supersonic flow solver was developed at Northrop Grumman based on the characteristic behavior of supersonic wave patterns emanating from the aircraft. Using this approach, it was possible to compute flow fields with adequate resolution several body lengths below the aircraft. In this region, three-dimensional effects are diminished and conventional two-dimensional modified linear theory (MLT) can be applied to estimate ground pressure signatures or sonic booms. To accommodate real aircraft geometries and alleviate the burdensome grid generation task, an implicit marching multi-block, multi-grid finite-volume Euler code was developed as the basis for the sonic boom prediction methodology. The Thomas two-dimensional extrapolation method is built into the Euler code so that ground signatures can be obtained quickly and efficiently with minimum computational effort suitable to the aircraft design environment. The loudness levels of these signatures can then be determined using a NASA generated noise code. Since the Euler code is a three-dimensional flow field solver, the complete circumferential region below the aircraft is computed. The extrapolation of all this field data from a cylinder of constant radius leads to the definition of the entire boom corridor occurring directly below and off to the side of the aircraft's flight path yielding an estimate for the entire noise "annoyance" corridor in miles as well as its magnitude. An automated multidisciplinary sonic boom design optimization software system was developed during the latter part of HSR Phase 1. Using this system, it was found that sonic boom signatures could be reduced through optimization of a variety of geometric aircraft parameters. This system uses a gradient based nonlinear optimizer as the driver in conjunction with a

  11. A study of sonic boom overpressure trends with respect to weight, altitude, Mach number, and vehicle shaping

    NASA Technical Reports Server (NTRS)

    Needleman, Kathy E.; Mack, Robert J.

    1990-01-01

    This paper presents and discusses trends in nose shock overpressure generated by two conceptual Mach 2.0 configurations. One configuration was designed for high aerodynamic efficiency, while the other was designed to produce a low boom, shaped-overpressure signature. Aerodynamic lift, sonic boom minimization, and Mach-sliced/area-rule codes were used to analyze and compute the sonic boom characteristics of both configurations with respect to cruise Mach number, weight, and altitude. The influence of these parameters on the overpressure and the overpressure trends are discussed and conclusions are given.

  12. Research on the sonic boom problem. Part 1: Second-order solutions for the flow field around slender bodies in supersonic flow for sonic boom analysis

    NASA Technical Reports Server (NTRS)

    Landahl, M.; Loefgren, P.

    1973-01-01

    A second-order theory for supersonic flow past slender bodies is presented. Through the introduction of characteristic coordinates as independent variables and the expansion procedure proposed by Lin and Oswatitsch, a uniformly valid solution is obtained for the whole flow field in the axisymmetric case and for far field in the general three-dimensional case. For distances far from the body the theory is an extension of Whitham's first-order solution and for the domain close to the body it is a modification of Van Dyke's second-order solution in the axisymmetric case. From the theory useful formulas relating flow deflections to the Whitham F-function are derived, which permits one to determine the sonic boom strength from wind tunnel measurements fairly close to the body.

  13. Validation of sonic boom propagation codes using SR-71 flight test data.

    PubMed

    Ivanteyeva, Lyudmila G; Kovalenko, Victor V; Pavlyukov, Evgeny V; Teperin, Leonid L; Rackl, Robert G

    2002-01-01

    The results of two sonic boom propagation codes, ZEPHYRUS (NASA) and BOOM (TsAGI), are compared with SR-71 flight test data from 1995. Options available in the computational codes are described briefly. Special processing methods are described which were applied to the experimental data. A method to transform experimental data at close ranges to the supersonic aircraft into initial data required by the codes was developed; it is applicable at any flight regime. Data are compared in near-, mid-, and far fields. The far-field observation aircraft recorded both direct and reflected waves. Comparison of computed and measured results shows good agreement with peak pressure, duration, and wave shape for direct waves, thus validating the computational codes. PMID:11837960

  14. Validation of sonic boom propagation codes using SR-71 flight test data

    NASA Astrophysics Data System (ADS)

    Ivanteyeva, Lyudmila G.; Kovalenko, Victor V.; Pavlyukov, Evgeny V.; Teperin, Leonid L.; Rackl, Robert G.

    2002-01-01

    The results of two sonic boom propagation codes, ZEPHYRUS (NASA) and BOOM (TsAGI), are compared with SR-71 flight test data from 1995. Options available in the computational codes are described briefly. Special processing methods are described which were applied to the experimental data. A method to transform experimental data at close ranges to the supersonic aircraft into initial data required by the codes was developed; it is applicable at any flight regime. Data are compared in near-, mid-, and far fields. The far-field observation aircraft recorded both direct and reflected waves. Comparison of computed and measured results shows good agreement with peak pressure, duration, and wave shape for direct waves, thus validating the computational codes.

  15. Preliminary results from the White Sands Missile Range sonic boom propagation experiment

    NASA Technical Reports Server (NTRS)

    Willshire, William L., Jr.; Devilbiss, David W.

    1992-01-01

    Sonic boom bow shock amplitude and rise time statistics from a recent sonic boom propagation experiment are presented. Distributions of bow shock overpressure and rise time measured under different atmospheric turbulence conditions for the same test aircraft are quite different. The peak overpressure distributions are skewed positively, indicating a tendency for positive deviations from the mean to be larger than negative deviations. Standard deviations of overpressure distributions measured under moderate turbulence were 40 percent larger than those measured under low turbulence. As turbulence increased, the difference between the median and the mean increased, indicating increased positive overpressure deviations. The effect of turbulence was more readily seen in the rise time distributions. Under moderate turbulence conditions, the rise time distribution means were larger by a factor of 4 and the standard deviations were larger by a factor of 3 from the low turbulence values. These distribution changes resulted in a transition from a peaked appearance of the rise time distribution for the morning to a flattened appearance for the afternoon rise time distributions. The sonic boom propagation experiment consisted of flying three types of aircraft supersonically over a ground-based microphone array with concurrent measurements of turbulence and other meteorological data. The test aircraft were a T-38, an F-15, and an F-111, and they were flown at speeds of Mach 1.2 to 1.3, 30,000 feet above a 16 element, linear microphone array with an inter-element spacing of 200 ft. In two weeks of testing, 57 supersonic passes of the test aircraft were flown from early morning to late afternoon.

  16. Effects of indoor rattle sounds on annoyance caused by sonic booms.

    PubMed

    Rathsam, Jonathan; Loubeau, Alexandra; Klos, Jacob

    2015-07-01

    To expand national air transportation capabilities, NASA's Commercial Supersonic Technology Project is working to make supersonic flight practical for commercial passengers. As an aid in designing and certifying quiet supersonic aircraft, a noise metric is sought that will correspond to indoor annoyance caused by sonic booms, including the effects of indoor rattle sounds. This study examines how well several common aircraft noise metrics predict indoor annoyance based on the indoor and outdoor sound fields. The results suggest notional community annoyance models that include the effects of indoor rattle sounds. PMID:26233059

  17. Effects of aircraft noise and sonic booms on domestic animals and wildlife: bibliographic abstracts

    USGS Publications Warehouse

    Gladwin, Douglas N.; Manci, Karen M.; Villella, Rita

    1988-01-01

    The purpose of this document is to provide an information base on the effects of aircraft noise and sonic booms on various animal species. Such information is necessary to assess potential impacts to wildlife populations from proposed military and other flight operations. To develop this document the National Ecology Center conducted a literature search of information pertaining to animals and wildlife. Information concerning other types of noise was also gathered to supplement the lack of knowledge on the effects of aircraft noise. The bibliographic abstracts in this report provide a compilation of current knowledge. No attempt was made to evaluate the appropriateness or adequacy of the scientific approach of each study.

  18. Vibro-Acoustic Response of Buildings Due to Sonic Boom Exposure: June 2006 Field Test

    NASA Technical Reports Server (NTRS)

    Klos, Jacob; Buehrle, Ralph D.

    2007-01-01

    During the month of June 2006, a series of structural response measurements were made on a house on Edwards Air Force Base (AFB) property that was excited by sonic booms of various amplitudes. Many NASA personnel other than the authors of this report from both Langley Research Center and Dryden Flight Research Center participated in the planning, coordination, execution, and data reduction for the experiment documented in this report. The purpose of this report is to document the measurements that were made, the structure on which they were made, the conditions under which they were made, the sensors and other hardware that were used, and the data that were collected.

  19. Flight test measurements and analysis of sonic boom phenomena near the shock wave extremity

    NASA Technical Reports Server (NTRS)

    Haglund, G. T.; Kane, E. J.

    1974-01-01

    A NASA flight test program conducted during the summer and fall of 1970 was devoted to investigating sonic boom phenomena near caustics formed by steady flight near the threshold Mach number, during accelerations, and at the lateral extremes of the ground carpet. The vertical extent of the shock waves attached to near-sonic airplanes was also studied. The flights were conducted over the 1500 ft instrumented BREN tower so that vertical surveys through the shock waves were measured. These data on caustic phenomena near the shock wave extremity were analyzed in detail and compared with theoretical results. Amplifications of shock wave strength varied from 2 to 5 during longitudinal accelerations, from 1 to 1.8 during steady threshold Mach number flight, and up to 3 for small inadvertent accelerations during flight near the threshold Mach number.

  20. Modified Linear Theory Aircraft Design Tools and Sonic Boom Minimization Strategy Applied to Signature Freezing via F-function Lobe Balancing

    NASA Astrophysics Data System (ADS)

    Jung, Timothy Paul

    Commercial supersonic travel has strong business potential; however, in order for the Federal Aviation Administration to lift its ban on supersonic flight overland, designers must reduce aircraft sonic boom strength to an acceptable level. An efficient methodology and associated tools for designing aircraft for minimized sonic booms are presented. The computer-based preliminary design tool, RapidF, based on modified linear theory, enables quick assessment of an aircraft's sonic boom with run times less than 30 seconds on a desktop computer. A unique feature of RapidF is that it tracks where on the aircraft each segment of the of the sonic boom came from, enabling precise modifications, speeding the design process. Sonic booms from RapidF are compared to flight test data, showing that it is capability of predicting a sonic boom duration, overpressure, and interior shock locations. After the preliminary design is complete, scaled flight tests should be conducted to validate the low boom design. When conducting such tests, it is insufficient to just scale the length; thus, equations to scale the weight and propagation distance are derived. Using RapidF, a conceptual supersonic business jet design is presented that uses F-function lobe balancing to create a frozen sonic boom using lifting surfaces. The leading shock is reduced from 1.4 to 0.83 psf, and the trailing shock from 1.2 to 0.87 psf, 41% and 28% reductions respectfully. By changing the incidence angle of the surfaces, different sonic boom shapes can be created, and allowing the lobes to be re-balanced for new flight conditions. Computational fluid dynamics is conducted to validate the sonic boom predictions. Off-design analysis is presented that varies weight, altitude, Mach number, and propagation angle, demonstrating that lobe-balance is robust. Finally, the Perceived Level of Loudness metric is analyzed, resulting in a modified design that incorporates other boom minimization techniques to further reduce

  1. Background Pressure Profiles for Sonic Boom Vehicle Testing in the NASA Glenn 8- by 6-Foot Supersonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Castner, Raymond; Shaw, Stephen; Adamson, Eric; Simerly, Stephanie

    2013-01-01

    In an effort to identify test facilities that offer sonic boom measurement capabilities, an exploratory test program was initiated using wind tunnels at NASA research centers. The subject of this report is the sonic boom pressure rail data collected in the Glenn Research Center 8- by 6-Foot Supersonic Wind Tunnel. The purpose is to summarize the lessons learned based on the test activity, specifically relating to collecting sonic boom data which has a large amount of spatial pressure variation. The wind tunnel background pressure profiles are presented as well as data which demonstrated how both wind tunnel Mach number and model support-strut position affected the wind tunnel background pressure profile. Techniques were developed to mitigate these effects and are presented.

  2. Exhaust Plume Effects on Sonic Boom for a Delta Wing and a Swept Wing-Body Model

    NASA Technical Reports Server (NTRS)

    Castner, Raymond; Lake, Troy

    2012-01-01

    Supersonic travel is not allowed over populated areas due to the disturbance caused by the sonic boom. Research has been performed on sonic boom reduction and has included the contribution of the exhaust nozzle plume. Plume effect on sonic boom has progressed from the study of isolated nozzles to a study with four exhaust plumes integrated with a wing-body vehicle. This report provides a baseline analysis of the generic wing-body vehicle to demonstrate the effect of the nozzle exhaust on the near-field pressure profile. Reductions occurred in the peak-to-peak magnitude of the pressure profile for a swept wing-body vehicle. The exhaust plumes also had a favorable effect as the nozzles were moved outward along the wing-span.

  3. Sonic Boom.

    ERIC Educational Resources Information Center

    Hurtig, Brent

    1998-01-01

    Reviews and evaluates Pro Tools 4.1, a multitrack digital audio workstation (DAWs) that imports and synchronizes to QuickTime or AVI digital movies. Audio-for-picture editors lock their digital audio workstations to linear videotape recorders, using complex, expensive time code synchronizers. Highlights Macintosh and Windows based alternatives.…

  4. Exhaust Nozzle Plume Effects on Sonic Boom Test Results for Isolated Nozzles

    NASA Technical Reports Server (NTRS)

    Castner, Raymond S.

    2011-01-01

    Reducing or eliminating the operational restrictions of supersonic aircraft over populated areas has led to extensive research at NASA. Restrictions were due to the disturbance of the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Recent work has been performed to reduce the magnitude of the sonic boom N-wave generated by airplane components with focus on shock waves caused by the exhaust nozzle plume. Previous Computational Fluid Dynamics (CFD) analysis showed how the shock wave formed at the nozzle lip interacts with the nozzle boat-tail expansion wave. An experiment was conducted in the 1- by 1-ft Supersonic Wind Tunnel at the NASA Glenn Research Center to validate the computational study. Results demonstrated how the nozzle lip shock moved with increasing nozzle pressure ratio (NPR) and reduced the nozzle boat-tail expansion, causing a favorable change in the observed pressure signature. Experimental results were presented for comparison to the CFD results. The strong nozzle lip shock at high values of NPR intersected the nozzle boat-tail expansion and suppressed the expansion wave. Based on these results, it may be feasible to reduce the boat-tail expansion for a future supersonic aircraft with under-expanded nozzle exhaust flow by modifying nozzle pressure or nozzle divergent section geometry.

  5. Sonic Boom Pressure Signature Uncertainty Calculation and Propagation to Ground Noise

    NASA Technical Reports Server (NTRS)

    West, Thomas K., IV; Bretl, Katherine N.; Walker, Eric L.; Pinier, Jeremy T.

    2015-01-01

    The objective of this study was to outline an approach for the quantification of uncertainty in sonic boom measurements and to investigate the effect of various near-field uncertainty representation approaches on ground noise predictions. These approaches included a symmetric versus asymmetric uncertainty band representation and a dispersion technique based on a partial sum Fourier series that allows for the inclusion of random error sources in the uncertainty. The near-field uncertainty was propagated to the ground level, along with additional uncertainty in the propagation modeling. Estimates of perceived loudness were obtained for the various types of uncertainty representation in the near-field. Analyses were performed on three configurations of interest to the sonic boom community: the SEEB-ALR, the 69o DeltaWing, and the LM 1021-01. Results showed that representation of the near-field uncertainty plays a key role in ground noise predictions. Using a Fourier series based dispersion approach can double the amount of uncertainty in the ground noise compared to a pure bias representation. Compared to previous computational fluid dynamics results, uncertainty in ground noise predictions were greater when considering the near-field experimental uncertainty.

  6. Development of a computer technique for the prediction of transport aircraft flight profile sonic boom signatures. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Coen, Peter G.

    1991-01-01

    A new computer technique for the analysis of transport aircraft sonic boom signature characteristics was developed. This new technique, based on linear theory methods, combines the previously separate equivalent area and F function development with a signature propagation method using a single geometry description. The new technique was implemented in a stand-alone computer program and was incorporated into an aircraft performance analysis program. Through these implementations, both configuration designers and performance analysts are given new capabilities to rapidly analyze an aircraft's sonic boom characteristics throughout the flight envelope.

  7. Design of an Indoor Sonic Boom Simulator at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Klos, Jacob; Sullivan, Brenda M.; Shepherd, Kevin P.

    2008-01-01

    Construction of a simulator to recreate the soundscape inside residential buildings exposed to sonic booms is scheduled to start during the summer of 2008 at NASA Langley Research Center. The new facility should be complete by the end of the year. The design of the simulator allows independent control of several factors that create the indoor soundscape. Variables that will be isolated include such factors as boom duration, overpressure, rise time, spectral shape, level of rattle, level of squeak, source of rattle and squeak, level of vibration and source of vibration. Test subjects inside the simulator will be asked to judge the simulated soundscape, which will represent realistic indoor boom exposure. Ultimately, this simulator will be used to develop a functional relationship between human response and the sound characteristics creating the indoor soundscape. A conceptual design has been developed by NASA personnel, and is currently being vetted through small-scale risk reduction tests that are being performed in-house. The purpose of this document is to introduce the conceptual design, identify how the indoor response will be simulated, briefly outline some of the risk reduction tests that have been completed to vet the design, and discuss the impact of these tests on the simulator design.

  8. Noise and sonic-boom impact technology. BOOMAP2 computer program for sonic-boom research. Volume 2. Program users/computer operations manual. Final report, July 86-November 1987

    SciTech Connect

    Day, P.J.; Reilly, T.M.; Seidman, H.

    1988-08-01

    The BOOMAP2 and MOAOPS computer programs analyze noise from supersonic aircraft operations by extracting information from a TACTS/ACMI mission standard data tape and compiles a computer library of information concerning the supersonic operations. The BOOMAP2 program utilizes the library produced by the MOAOPS program. The program calculates various statistics on the supersonic operations, and calculates expected sonic boom levels on the ground based on the extracted information. BOOMAP2 can: 1) generate various spatial/temporal distribution statistics; 2) interface with sonic boom generation and propagation models; 3) calculate the intensity and location of sonic booms reaching the ground; and 4) provide the data file used by a commercial graphical software package, GPCP, to plot contours of boom exposure in units of average peak overpressure or C-weighted day-night average sound level (CDNL). These two programs, when used with an adequate library of aircraft sorties from Military Operating Areas, can be an invaluable tool for environmental planning purposes to predict boom intensity, frequency, and distribution. This report provides the program user's manual and computer operation's manual for the BOOMAP2 program developed under this contract.

  9. Feasibility study on conducting overflight measurements of shaped sonic boom signatures using the Firebee BQM-34E RPV

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Sothcott, Victor E.; Keefer, Thomas N., Jr.

    1993-01-01

    A study was performed to determine the feasibility of establishing if a 'shaped' sonic boom signature, experimentally shown in wind tunnel models out to about 10 body lengths, will persist out to representative flight conditions of 200 to 300 body lengths. The study focuses on the use of a relatively large supersonic remotely-piloted and recoverable vehicle. Other simulation methods that may accomplish the objective are also addressed and include the use of nonrecoverable target drones, missiles, full-scale drones, very large wind tunnels, ballistic facilities, whirling-arm techniques, rocket sled tracks, and airplane nose probes. In addition, this report will also present a background on the origin of the feasibility study including a brief review of the equivalent body concept, a listing of the basic sonic boom signature characteristics and requirements, identification of candidate vehicles in terms of desirable features/availability, and vehicle characteristics including geometries, area distributions, and resulting sonic boom signatures. A program is developed that includes wind tunnel sonic boom and force models and tests for both a basic and modified vehicles and full-scale flight tests.

  10. Godunov method and computer program to determine the pressure and flow field associated with a sonic boom focus

    NASA Technical Reports Server (NTRS)

    Parker, L. W.; Zalosh, R. G.

    1973-01-01

    A computer method has been developed to calculate the flow field associated with sonic boom focusing. Solutions are obtained for focussing caused by localized cold spots in the atmosphere, as well as for N-waves with concave fronts. Results include focus factors and the length scales of the focal region. Both strong and weak shock waves are studied.

  11. Feasibility study on conducting overflight measurements of shaped sonic boom signatures using the Firebee BQM-34E RPV

    NASA Astrophysics Data System (ADS)

    Maglieri, Domenic J.; Sothcott, Victor E.; Keefer, Thomas N., Jr.

    1993-02-01

    A study was performed to determine the feasibility of establishing if a 'shaped' sonic boom signature, experimentally shown in wind tunnel models out to about 10 body lengths, will persist out to representative flight conditions of 200 to 300 body lengths. The study focuses on the use of a relatively large supersonic remotely-piloted and recoverable vehicle. Other simulation methods that may accomplish the objective are also addressed and include the use of nonrecoverable target drones, missiles, full-scale drones, very large wind tunnels, ballistic facilities, whirling-arm techniques, rocket sled tracks, and airplane nose probes. In addition, this report will also present a background on the origin of the feasibility study including a brief review of the equivalent body concept, a listing of the basic sonic boom signature characteristics and requirements, identification of candidate vehicles in terms of desirable features/availability, and vehicle characteristics including geometries, area distributions, and resulting sonic boom signatures. A program is developed that includes wind tunnel sonic boom and force models and tests for both a basic and modified vehicles and full-scale flight tests.

  12. Sonic booms of space shuttles approaching Edwards Air Force Base, 1988-1993.

    PubMed

    Young, Robert W

    2002-01-01

    From 1988 to 1993 13 sonic booms of space shuttles approaching Edwards Air Force Base were measured at a site 10 miles west of EAFB, with one to seven different sound level meters for each measurement. Results from five of these measurements are here presented. Maximum differences in measured levels between instruments for the same flight varied from 0 to 6 dB depending on the measurement descriptor and model of sound level meter. The average difference between predicted and measured values was 0.7+/-1.5 dB. For sound level meters with adequate bandwidth the waveforms measured varied from a near perfect N-wave to a more distorted form reflecting the influence of the varying condition of the atmosphere during propagation to the ground. PMID:11837962

  13. Response of laminated composite flat panels to sonic boom and explosive blast loadings

    NASA Technical Reports Server (NTRS)

    Librescu, L.; Nosier, A.

    1990-01-01

    This paper deals with a theoretical analysis of the dynamic response of shear deformable symmetrically laminated rectangular composite flat panels exposed to sonic boom and explosive blast loadings. The pertinent governing equations incorporating transverse shear deformation, transverse normal stress, as well as the higher-order effects are solved by using the integral-transform technique. The obtained results are compared with their counterparts obtained within the framework of the first-order transverse shear deformation and the classical plate theories and some conclusions concerning their range of applicability are outlined. The paper also contains a detailed analysis of the influence played by the various parameters characterizing the considered pressure pulses as well as the material and geometry of the plate.

  14. Analysis of the Effects of Streamwise Lift Distribution on Sonic Boom Signature

    NASA Technical Reports Server (NTRS)

    Yoo, Seung Yeun (Paul)

    2010-01-01

    The streamwise lift distribution of a wing-canard-stabilator-body configuration was varied to study its effect on the near-field sonic boom signature. The investigation was carried out via solving the three-dimensional Euler equation with the OVERFLOW-2 flow solver. The computational meshes were created using the Chimera overset grid topology. The lift distribution was varied by first deflecting the canard then trimming the aircraft with the wing and the stabilator while maintaining constant lift coefficient of 0.05. A validation study using experimental results was also performed to determine required grid resolution and appropriate numerical scheme. A wide range of streamwise lift distribution was simulated. The result shows that the longitudinal wave propagation speed can be controlled through lift distribution thus controlling the shock coalescence.

  15. Subjective loudness and annoyance of filtered N-wave sonic booms.

    PubMed

    Niedzwiecki, A; Ribner, H S

    1979-03-01

    The contribution of the "infrasonic" low-frequency content of sonic boom N waves to subjective loudness and annoyance has been investigated. An extended low-frequency response loudspeaker-driven simulation booth was employed, with computer-generated input test signals. For test N waves of 1 ms rise time and 150 ms duration, frequencies below 25 and 50 Hz, respectively, were cut off by digital filters simulating simple RC circuits. The filtered signal amplitude was adjusted versus the amplitude (48 Pa) of a reference unfiltered N wave (effective low-frequency cutoff approximately 0.1 Hz) until the two sounded equally loud (first experiment) or equally annoying (second experiment). The amplitude differences for equality were very slight: less than 0.6 dB at most. Surprisingly, while loss of the low frequencies slightly decreased the loudness, it slightly increased the annoyance. PMID:447906

  16. Overview of an Indoor Sonic Boom Simulator at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Klos, Jacob

    2012-01-01

    A facility has been constructed at NASA Langley Research Center to simulate the soundscape inside residential houses that are exposed to environmental noise from aircraft. This controllable indoor listening environment, the Interior Effects Room, enables systematic study of parameters that affect psychoacoustic response. The single-room facility, built using typical residential construction methods and materials, is surrounded on adjacent sides by two arrays of loudspeakers in close proximity to the exterior walls. The arrays, containing 52 subwoofers and 52 mid-range speakers, have a usable bandwidth of 3 Hz to 5 kHz and sufficient output to allow study of sonic boom noise. In addition to these exterior arrays, satellite speakers placed inside the room are used to augment the transmitted sound with rattle and other audible contact ]induced noise that can result from low frequency excitation of a residential house. The layout of the facility, operational characteristics, acoustic characteristics and equalization approaches are summarized.

  17. Effects of Sonic Booms on Marine Mammals: Problem Review and Recommended Research

    NASA Technical Reports Server (NTRS)

    Bowles, Ann E.

    1996-01-01

    By flying the High-Speed Civil Transport (HSCT) exclusively over uninhabited areas and mo over water, human annoyance will be reduced to acceptable levels. However, this strategy will for HSCT proponents to contend with the potential effects of sonic booms on animals, particularly ma mammals. What follows is a summary of the environmental regulations that must be addressed, the scientific community's concerns about the potential effects of the HSCT, and recommendations fox research to address the most important concerns. The recommendations included herein are based both on existing scientific evidence and regulatory needs. One cannot over-emphasize the importance of obtaining the appropriate information prior to substantial public exposure. Recent controversies over other human-made acoustic sources in the ocean suggest that the HSCT will receive intense scrutiny. It seems certain that an Environmental Impact Statement (EIS) and Incidental Harassment Authorization (IHA) under the Marine Mammal Protection Act (MMPA) or its equivalent will be necessary.

  18. Analysis of the Effects of Streamwise Lift Distribution on Sonic Boom Signature

    NASA Technical Reports Server (NTRS)

    Yoo, Paul

    2013-01-01

    Investigation of sonic boom has been one of the major areas of study in aeronautics due to the benefits a low-boom aircraft has in both civilian and military applications. This work conducts a numerical analysis of the effects of streamwise lift distribution on the shock coalescence characteristics. A simple wing-canard-stabilator body model is used in the numerical simulation. The streamwise lift distribution is varied by fixing the canard at a deflection angle while trimming the aircraft with the wing and the stabilator at the desired lift coefficient. The lift and the pitching moment coefficients are computed using the Missile DATCOM v. 707. The flow field around the wing-canard- stabilator body model is resolved using the OVERFLOW-2 flow solver. Overset/ chimera grid topology is used to simplify the grid generation of various configurations representing different streamwise lift distributions. The numerical simulations are performed without viscosity unless it is required for numerical stability. All configurations are simulated at Mach 1.4, angle-of-attack of 1.50, lift coefficient of 0.05, and pitching moment coefficient of approximately 0. Four streamwise lift distribution configurations were tested.

  19. A unified approach to an augmented Burgers equation for the propagation of sonic booms.

    PubMed

    Yamamoto, Masafumi; Hashimoto, Atsushi; Aoyama, Takashi; Sakai, Takeharu

    2015-04-01

    Nonlinear propagation through a relaxing atmosphere of pressure disturbances extracted from a computational fluid dynamics (CFD) solution of the flow around a supersonic aircraft is simulated using an augmented Burgers equation. The effects of nonlinearity, geometrical spreading, atmospheric inhomogeneity, thermoviscous attenuation, and molecular vibration relaxation are taken into account. The augmented Burgers equation used for sonic boom propagation calculations is often solved by the operator splitting method, but numerical difficulties arise with this approach when dissipation is not effective. By re-examining the solution algorithms for the augmented Burgers equation, a stable method for handling the relaxation effect has been developed. This approach can handle the Burgers equation in a unified manner without operator splitting and, therefore, the resulting scheme is twice as fast as the original one. The approach is validated by comparing it with an analytical solution and a detailed CFD of dispersed plane wave propagation. In addition, a rise time prediction of low-boom supersonic aircraft is demonstrated. PMID:25920838

  20. Vibro-Acoustic Response of Buildings Due to Sonic Boom Exposure: July 2007 Field Test

    NASA Technical Reports Server (NTRS)

    Klos, Jacob

    2008-01-01

    During the month of July 2007, a series of structural response measurements were made on a house on Edwards Air Force Base (EAFB) property that was exposed to sonic booms of various amplitudes. The purpose of this report is to document the measurements that were made, the structure on which they were made, the conditions under which they were made, the sensors and other hardware that were used, and the data that were collected. To that end, Chapter 2 documents the house, its location, the physical layout of the house, the surrounding area, and summarizes the transducers placed in and around the house. Chapter 3 details the sensors and other hardware that were placed in the house during the experiment. In addition, day-to-day variations of hardware configurations and transducer calibrations are documented in Chapter 3. Chapter 4 documents the boom generation process, flight conditions, and ambient weather conditions during the test days. Chapter 5 includes information about sub-experiments that were performed to characterize the vibro-acoustic response of the structure, the acoustic environment inside the house, and the acoustic environment outside the house. Chapter 6 documents the data format and presents examples of reduced data that were collected during the test days.

  1. Vibration Responses of Test Structure No. 2 During the Edward Air Force Base Phase of the National Sonic Boom Program

    NASA Technical Reports Server (NTRS)

    Findley, D. S.; Huckel, V.; Hubbard, H. H.

    1975-01-01

    In order to evaluate reaction of people to sonic booms of varying overpressures and time durations, a series of closely controlled and systematic flight tests/studies were conducted from June 3 to June 23, 1966. The dynamic responses of several building structures were measured, with emphasis on a two-story residence structure. Sample acceleration and strain recordings from F-104, B-58, and XB-70 sonic boom exposures are included, along with tabulations of the maximum acceleration and strain values measured for each one of about 140 flight tests. These data are compared with similar measurements for engine noise exposures of the building during simulated landing approaches and takeoffs of KC-135 aircraft.

  2. A study of the sonic-boom characteristics of a blunt body at a Mach number of 4.14

    NASA Technical Reports Server (NTRS)

    Carlson, H. W.; Mack, R. J.

    1977-01-01

    An experimental and theoretical study has shown that the applicability of far-field sonic-boom theory previously demonstrated for more slender shapes may now be extended to bodies with ratios of diameter to length as great as 2 and to Mach numbers at least as high as 4.14. This finding is of special significance in view of the limitations to the use of existing methods for the extrapolation of close-in experimental data.

  3. Cart3D Simulations for the First AIAA Sonic Boom Prediction Workshop

    NASA Technical Reports Server (NTRS)

    Aftosmis, Michael J.; Nemec, Marian

    2014-01-01

    Simulation results for the First AIAA Sonic Boom Prediction Workshop (LBW1) are presented using an inviscid, embedded-boundary Cartesian mesh method. The method employs adjoint-based error estimation and adaptive meshing to automatically determine resolution requirements of the computational domain. Results are presented for both mandatory and optional test cases. These include an axisymmetric body of revolution, a 69deg delta wing model and a complete model of the Lockheed N+2 supersonic tri-jet with V-tail and flow through nacelles. In addition to formal mesh refinement studies and examination of the adjoint-based error estimates, mesh convergence is assessed by presenting simulation results for meshes at several resolutions which are comparable in size to the unstructured grids distributed by the workshop organizers. Data provided includes both the pressure signals required by the workshop and information on code performance in both memory and processing time. Various enhanced techniques offering improved simulation efficiency will be demonstrated and discussed.

  4. Summary and Statistical Analysis of the First AIAA Sonic Boom Prediction Workshop

    NASA Technical Reports Server (NTRS)

    Park, Michael A.; Morgenstern, John M.

    2014-01-01

    A summary is provided for the First AIAA Sonic Boom Workshop held 11 January 2014 in conjunction with AIAA SciTech 2014. Near-field pressure signatures extracted from computational fluid dynamics solutions are gathered from nineteen participants representing three countries for the two required cases, an axisymmetric body and simple delta wing body. Structured multiblock, unstructured mixed-element, unstructured tetrahedral, overset, and Cartesian cut-cell methods are used by the participants. Participants provided signatures computed on participant generated and solution adapted grids. Signatures are also provided for a series of uniformly refined workshop provided grids. These submissions are propagated to the ground and loudness measures are computed. This allows the grid convergence of a loudness measure and a validation metric (dfference norm between computed and wind tunnel measured near-field signatures) to be studied for the first time. Statistical analysis is also presented for these measures. An optional configuration includes fuselage, wing, tail, flow-through nacelles, and blade sting. This full configuration exhibits more variation in eleven submissions than the sixty submissions provided for each required case. Recommendations are provided for potential improvements to the analysis methods and a possible subsequent workshop.

  5. Plume and Shock Interaction Effects on Sonic Boom in the 1-foot by 1-foot Supersonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Castner, Raymond; Elmiligui, Alaa; Cliff, Susan; Winski, Courtney

    2015-01-01

    The desire to reduce or eliminate the operational restrictions of supersonic aircraft over populated areas has led to extensive research at NASA. Restrictions are due to the disturbance of the sonic boom, caused by the coalescence of shock waves formed by the aircraft. A study has been performed focused on reducing the magnitude of the sonic boom N-wave generated by airplane components with a focus on shock waves caused by the exhaust nozzle plume. Testing was completed in the 1-foot by 1-foot supersonic wind tunnel to study the effects of an exhaust nozzle plume and shock wave interaction. The plume and shock interaction study was developed to collect data for computational fluid dynamics (CFD) validation of a nozzle plume passing through the shock generated from the wing or tail of a supersonic vehicle. The wing or tail was simulated with a wedgeshaped shock generator. This test entry was the first of two phases to collect schlieren images and off-body static pressure profiles. Three wedge configurations were tested consisting of strut-mounted wedges of 2.5- degrees and 5-degrees. Three propulsion configurations were tested simulating the propulsion pod and aft deck from a low boom vehicle concept, which also provided a trailing edge shock and plume interaction. Findings include how the interaction of the jet plume caused a thickening of the shock generated by the wedge (or aft deck) and demonstrate how the shock location moved with increasing nozzle pressure ratio.

  6. A Comparison of Computer Codes for the Propagation of Sonic Booms Through Realistic Atmospheres Utilizing Actual Acoustic Signatures

    NASA Technical Reports Server (NTRS)

    Chambers, James P.; Cleveland, Robin O.; Bass, David T.; Raspet, Richard; Blackstock, David T.; Hamilton, Mark F.

    1996-01-01

    A numerical exercise to compare computer codes for the propagation of sonic booms through the atmosphere is reported. For the initial portion of the comparison, artificial, yet realistic, waveforms were numerically propagated through identical atmospheres. In addition to this comparison, one of these codes has been used to make preliminary predictions of the boom generated from a recent SR-71 flight. For the initial comparison, ground waveforms are calculated using four different codes or algorithms: (1) weak shock theory, an analytical prediction, (2) SHOCKN, a mixed time and frequency domain code developed at the University of Mississippi, (3) ZEPHYRUS, another mixed time and frequency code developed at the University of Texas, and (4) THOR, a pure time domain code recently developed at the University of Texas. The codes are described and their differences noted.

  7. Understanding sources of uncertainty and bias error in models of human response to low amplitude sonic booms

    NASA Astrophysics Data System (ADS)

    Collmar, M.; Cook, B. G.; Cowart, R.; Freund, D.; Gavin, J.

    2015-10-01

    A pool of 240 subjects was exposed to a library of waveforms consisting of example signatures of low boom aircraft. The signature library included intentional variations in both loudness and spectral content, and were auralized using the Gulfstream SASS-II sonic boom simulator. Post-processing was used to quantify the impacts of test design decisions on the "quality" of the resultant database. Specific lessons learned from this study include insight regarding potential for bias error due to variations in loudness or peak over-pressure, sources of uncertainty and their relative importance on objective measurements and robustness of individual metrics to wide variations in spectral content. Results provide clear guidance for design of future large scale community surveys, where one must optimize the complex tradeoffs between the size of the surveyed population, spatial footprint of those participants, and the fidelity/density of objective measurements.

  8. Evidence of wave front folding of sonic booms by a laboratory-scale deterministic experiment of shock waves in a heterogeneous medium.

    PubMed

    Ganjehi, Lili; Marchiano, Régis; Coulouvrat, François; Thomas, Jean-Louis

    2008-07-01

    The influence of the planetary boundary layer on the sonic boom received at the ground level is known since the 1960s to be of major importance. Sonic boom propagation in a turbulent medium is characterized by an increase of the mean rise time and a huge variability. An experiment is conducted at a 1:100,000 scale in water to investigate ultrasonic shock wave interaction with a single heterogeneity. The experiment shows a very good scaling with sonic boom, concerning the size of the heterogeneities, the wave amplitude, and the rise time of the incident wave. The wave front folding associated with local focusing, and its link to the increase of the rise time, are evidenced by the experiment. The observed amplification of the peak pressure (by a factor up to 2), and increase of the rise time (by up to about one magnitude order), are in qualitative agreement with sonic boom observations. A nonlinear parabolic model is compared favorably to the experiment on axis, though the paraxial approximation turns out less precise off axis. Simulations are finally used to discriminate between nonlinear and linear propagations, showing nonlinearities affect mostly the higher harmonics that are in the audible range for sonic booms. PMID:18646955

  9. Vibration responses of two house structures during the Edwards Air Force Base phase of the national sonic boom program

    NASA Technical Reports Server (NTRS)

    Hubbard, Harvey H.

    1990-01-01

    The data are reproduced from NSBEO-1-67, which contains some preliminary results of the test program, and from NASA-Langley working papers 259 and 288 which are now out of print. Included are sample acceleration and strain recordings from F-104, B-58, and XB-70 sonic boom exposures, along with tabulations of the maximum acceleration and strain values measured for each one of about 130 flight tests. These data are compared with similar measurements for engine noise exposures of the building during simulated landing approaches and takeoffs of KC-135 aircraft.

  10. Sonic-boom measurements for SR-71 aircraft operating at Mach numbers to 3.0 and altitudes to 24384 meters

    NASA Technical Reports Server (NTRS)

    Maglieri, D. J.; Huckel, V.; Henderson, H. R.

    1972-01-01

    Sonic-boom pressure signatures produced by the SR-71 aircraft at altitudes from 10,668 to 24,384 meters and Mach numbers 1.35 to 3.0 were obtained as an adjunct to the sonic boom evaluation program relating to structural and subjective response which was conducted in 1966-1967 time period. Approximately 2000 sonic-boom signatures from 33 flights of the SR-71 vehicle and two flights of the F-12 vehicle were recorded. Measured ground-pressure signatures for both on-track and lateral measuring station locations are presented and the statistical variations of the overpressure, positive impulse, wave duration, and shock-wave rise time are illustrated.

  11. Turbulence Scales, Rise Times, Caustics, and the Simulation of Sonic Boom Propagation

    NASA Technical Reports Server (NTRS)

    Pierce, Allan D.

    1996-01-01

    The general topic of atmospheric turbulence effects on sonic boom propagation is addressed with especial emphasis on taking proper and efficient account of the contributions of the portion oi the turbulence that is associated with extremely high wavenumber components. The recent work reported by Bart Lipkens in his doctoral thesis is reexamined to determine whether the good agreement between his measured rise times with the 1971 theory of the author is fortuitous. It is argued that Lipken's estimate of the distance to the first caustic was a gross overestimate because of the use of a sound speed correlation function shaped like a gaussian curve. In particular, it is argued that the expected distance to the first caustic varies with the kinematic viscosity nu and the energy epsilon dissipated per unit mass per unit time, and the sound speed c as : d(sub first caustic) = nu(exp 7/12) c(exp 2/3)/ epsilon(exp 5/12)(nu x epsilon/c(exp 4))(exp a), where the exponent a is greater than -7/12 and can be argued to be either O or 1/24. In any event, the surprising aspect of the relationship is that it actually goes to zero as the viscosity goes to zero with s held constant. It is argued that the apparent overabundance of caustics can be grossly reduced by a general computational and analytical perspective that partitions the turbulence into two parts, divided by a wavenumber k(sub c). Wavenumbers higher than kc correspond to small-scale turbulence, and the associated turbulence can be taken into account by a renormalization of the ambient sound speed so that the result has a small frequency dependence that results from a spatial averaging over of the smaller-scale turbulent fluctuations. Selection of k(sub c). can be made so large that only a very small number of caustics are encountered if one adopts the premise that the frequency dispersion of pulses is caused by that part of the turbulence spectrum which lies in the inertial range originally predicted by Kolmogoroff. The

  12. A Whitham-Theory Sonic-Boom Analysis of the TU-144 Aircraft at a Mach Number of 2.2

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    1999-01-01

    Officially, the Tu-144 was the first supersonic-cruise, passenger-carrying aircraft to enter commercial service. Design, construction, and testing were carried out by the Soviet Union, flight certification was by the Soviet Union, and the only regular passenger flights were scheduled and flown across the territory of the Soviet Union. Although it was not introduced to international passenger service, there were many significant engineering accomplishments achieved in the design, production, and flight of this aircraft. Development of the aircraft began with a prototype stage. Systematic testing and redesign led to a production aircraft in discrete stages that measurably improved the performance of the aircraft from the starting concept to final aircraft certification. It flew in competition with the English-French Concorde for a short time, but was withdrawn from national commercial service due to a lack of interest by airlines outside the Soviet Union. NASA became interested in the Tu- 144 aircraft when it was offered for use as a flying "testbed" in the study of operating characteristics of a supersonic-cruise commercial airplane. Since it had been in supersonic-cruise service, the Tu- 144 had operational characteris'tics similar to those anticipated in the conceptual aircraft designs being studied by the United States aircraft companies. In addition to the other operational tests being conducted on the Tu-144 aircraft, it was proposed that two sets of sonic-boom pressure signature measurements be made. The first set would be made on the ground, using techniques and devices similar to those in reference I and many other subsequent studies. A second set would be made in the air with an instrumented aircraft flying close under the Tu-144 in supersonic flight. Such in-flight measurements would require pressure gages that were capable of accurately recording the flow-field overpressures generated by the Tu- 144 at relatively close distances under the vehicle

  13. Non linear shock wave propagation in heterogeneous fluids: a numerical approach beyond the parabolic approximation with application to sonic boom.

    NASA Astrophysics Data System (ADS)

    Dagrau, Franck; Coulouvrat, François; Marchiano, Régis; Héron, Nicolas

    2008-06-01

    Dassault Aviation as a civil aircraft manufacturer is studying the feasibility of a supersonic business jet with the target of an "acceptable" sonic boom at the ground level, and in particular in case of focusing. A sonic boom computational process has been performed, that takes into account meteorological effects and aircraft manoeuvres. Turn manoeuvres and aircraft acceleration create zones of convergence of rays (caustics) which are the place of sound amplification. Therefore two elements have to be evaluated: firstly the geometrical position of the caustics, and secondly the noise level in the neighbourhood of the caustics. The modelling of the sonic boom propagation is based essentially on the assumptions of geometrical acoustics. Ray tracing is obtained according to Fermat's principle as paths that minimise the propagation time between the source (the aircraft) and the receiver. Wave amplitude and time waveform result from the solution of the inviscid Burgers' equation written along each individual ray. The "age variable" measuring the cumulative nonlinear effects is linked to the ray tube area. Caustics are located as the place where the ray tube area vanishes. Since geometrical acoustics does not take into account diffraction effects, it breaks down in the neighbourhood of caustics where it would predict unphysical infinite pressure amplitude. The aim of this study is to describe an original method for computing the focused noise level. The approach involves three main steps that can be summarised as follows. The propagation equation is solved by a forward marching procedure split into three successive steps: linear propagation in a homogeneous medium, linear perturbation due to the weak heterogeneity of the medium, and non-linear effects. The first step is solved using an "exact" angular spectrum algorithm. Parabolic approximation is applied only for the weak perturbation due to the heterogeneities. Finally, non linear effects are performed by solving the

  14. Analysis of sonic boom measurements near shock wave extremities for flight near Mach 1.0 and for airplane accelerations

    NASA Technical Reports Server (NTRS)

    Haglund, G. T.; Kane, E. J.

    1974-01-01

    The analysis of the 14 low-altitude transonic flights showed that the prevailing meteorological consideration of the acoustic disturbances below the cutoff altitude during threshold Mach number flight has shown that a theoretical safe altitude appears to be valid over a wide range of meteorological conditions and provides a reasonable estimate of the airplane ground speed reduction to avoid sonic boom noise during threshold Mach number flight. Recent theoretical results for the acoustic pressure waves below the threshold Mach number caustic showed excellent agreement with observations near the caustic, but the predicted overpressure levels were significantly lower than those observed far from the caustic. The analysis of caustics produced by inadvertent low-magnitude accelerations during flight at Mach numbers slightly greater than the threshold Mach number showed that folds and associated caustics were produced by slight changes in the airplane ground speed. These caustic intensities ranged from 1 to 3 time the nominal steady, level flight intensity.

  15. Method for Standardizing Sonic-Boom Model Pressure Signatures Measured at Several Wind-Tunnel Facilities

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    2007-01-01

    Low-boom model pressure signatures are often measured at two or more wind-tunnel facilities. Preliminary measurements are made at small separation distances in a wind tunnel close at hand, and a second set of pressure signatures is measured at larger separation distances in a wind-tunnel facility with a larger test section. In this report, a method for correcting and standardizing the wind-tunnel-measured pressure signatures obtained in different wind tunnel facilities is presented and discussed.

  16. Performance of a Supersonic Over-Wing Inlet with Application to a Low-Sonic-Boom Aircraft

    NASA Technical Reports Server (NTRS)

    Trefny, Charles J.; Hirt, Stefanie M.; Anderson, Bernhard H.; Fink, Lawrence E.; Magee, Todd E.

    2014-01-01

    Development of commercial supersonic aircraft has been hindered by many related factors including fuel-efficiency, economics, and sonic-boom signatures that have prevented over-land flight. Materials, propulsion, and flight control technologies have developed to the point where, if over-land flight were made possible, a commercial supersonic transport could be economically viable. Computational fluid dynamics, and modern optimization techniques enable designers to reduce the boom signature of candidate aircraft configurations to acceptable levels. However, propulsion systems must be carefully integrated with these low-boom configurations in order that the signatures remain acceptable. One technique to minimize the downward propagation of waves is to mount the propulsion systems above the wing, such that the wing provides shielding from shock waves generated by the inlet and nacelle. This topmounted approach introduces a number of issues with inlet design and performance especially with the highly-swept wing configurations common to low-boom designs. A 1.79%-scale aircraft model was built and tested at the NASA Glenn Research Center's 8-by 6-Foot Supersonic Wind Tunnel (8x6 SWT) to validate the configuration's sonic boom signature. In order to evaluate performance of the top-mounted inlets, the starboard flow-through nacelle on the aerodynamic model was replaced by a 2.3%-scale operational inlet model. This integrated configuration was tested at the 8x6 SWT from Mach 0.25 to 1.8 over a wide range of angles-of-attack and yaw. The inlet was also tested in an isolated configuration over a smaller range of angles-of-attack and yaw. A number of boundary-layer bleed configurations were investigated and found to provide a substantial positive impact on pressure recovery and distortion. Installed inlet performance in terms of mass capture, pressure recovery, and distortion over the Mach number range at the design angle-of-attack of 4-degrees is presented herein and compared

  17. Evaluation of Grid Modification Methods for On- and Off-Track Sonic Boom Analysis

    NASA Technical Reports Server (NTRS)

    Nayani, Sudheer N.; Campbell, Richard L.

    2013-01-01

    Grid modification methods have been under development at NASA to enable better predictions of low boom pressure signatures from supersonic aircraft. As part of this effort, two new codes, Stretched and Sheared Grid - Modified (SSG) and Boom Grid (BG), have been developed in the past year. The CFD results from these codes have been compared with ones from the earlier grid modification codes Stretched and Sheared Grid (SSGRID) and Mach Cone Aligned Prism (MCAP) and also with the available experimental results. NASA's unstructured grid suite of software TetrUSS and the automatic sourcing code AUTOSRC were used for base grid generation and flow solutions. The BG method has been evaluated on three wind tunnel models. Pressure signatures have been obtained up to two body lengths below a Gulfstream aircraft wind tunnel model. Good agreement with the wind tunnel results have been obtained for both on-track and off-track (up to 53 degrees) cases. On-track pressure signatures up to ten body lengths below a Straight Line Segmented Leading Edge (SLSLE) wind tunnel model have been extracted. Good agreement with the wind tunnel results have been obtained. Pressure signatures have been obtained at 1.5 body lengths below a Lockheed Martin aircraft wind tunnel model. Good agreement with the wind tunnel results have been obtained for both on-track and off-track (up to 40 degrees) cases. Grid sensitivity studies have been carried out to investigate any grid size related issues. Methods have been evaluated for fully turbulent, mixed laminar/turbulent and fully laminar flow conditions.

  18. Sonic-boom measurements in the focus region during the ascent of Apollo 17. [maximum positive overpressure, positive impulse, signature duration, and bow-shock rise time

    NASA Technical Reports Server (NTRS)

    Henderson, H. R.; Hilton, D. A.

    1974-01-01

    Sonic-boom pressure signatures recorded during the ascent phase of Apollo 17 are presented. The measurements were obtained onboard six U.S. Navy ships positioned along the ground track of the spacecraft vehicle in the area of expected focus resulting from the flight path and acceleration of the vehicle. Tracings of the measured signatures are presented along with values of the maximum positive overpressure, positive impulse, signature duration, and bowshock rise time. Also included are brief descriptions of the ships and their location, the deployment of the sonic-boom instrumentation, flight profiles and operating conditions for the launch vehicle and spacecraft, surface-weather and sea-state information at the measuring sites, and high-altitude weather information for the general measurement areas. Comparisons of the measured and predicted sonic-boom overpressures for the Apollo 17 mission are presented. The measured data are also compared with data from the Apollo 15 and 16 missions and data from flight test programs of various aircraft.

  19. Summary of Sonic Boom Rise Times Observed During FAA Community Response Studies over a 6-Month Period in the Oklahoma City Area

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Sothcott, Victor E.

    1990-01-01

    The sonic boom signature data acquired from about 1225 supersonic flights, over a 6-month period in 1964 in the Oklahoma City area, was enhanced with the addition of data relating to rise times and total signature duration. These later parameters, not available at the time of publication of the original report on the Oklahoma City sonic boom exposures, are listed in tabular form along with overpressure, positive impulse, positive duration, and waveform category. Airplane operating information along with the surface weather observations are also included. Sonic boom rise times include readings to the 1/2, 3/4, and maximum overpressure values. Rise time relative probabilities for various lateral locations from the ground track of 0, 5, and 10 miles are presented along with the variation of rise times with flight altitude. The tabulated signature data, along with corresponding airplane operating conditions and surface and upper level atmospheric information, are also available on electronic files to provide it in the format for more efficient and effective utilization.

  20. Study of the characteristics of seismic signals generated by natural and cultural phenomena. [such as earthquakes, sonic booms, and nuclear explosions

    NASA Technical Reports Server (NTRS)

    Goforth, T. T.; Rasmussen, R. K.

    1974-01-01

    Seismic data recorded at the Tonto Forest Seismological Observatory in Arizona and the Uinta Basin Seismological Observatory in Utah were used to compare the frequency of occurrence, severity, and spectral content of ground motions resulting from earthquakes, and other natural and man-made sources with the motions generated by sonic booms. A search of data recorded at the two observatories yielded a classification of over 180,000 earthquake phase arrivals on the basis of frequency of occurrence versus maximum ground velocity. The majority of the large ground velocities were produced by seismic surface waves from moderate to large earthquakes in the western United States, and particularly along the Pacific Coast of the United States and northern Mexico. A visual analysis of raw film seismogram data over a 3-year period indicates that local and regional seismic events, including quarry blasts, are frequent in occurrence, but do not produce ground motions at the observatories comparable to either the large western United States earthquakes or to sonic booms. Seismic data from the Nevada Test Site nuclear blasts were used to derive magnitude-distance-sonic boom overpressure relations.

  1. The effects of elastic supports on the transient vibroacoustic response of a window caused by sonic booms.

    PubMed

    Ou, Dayi; Mak, Cheuk Ming

    2011-08-01

    The transient vibration and sound radiation (TVSR) of plate-like structures with general elastic boundary conditions was investigated using the time-domain finite element method (TDFEM) and time-domain boundary element method (TDBEM). In this model, the structure can have arbitrary elastic boundary conditions and hence the effects of the boundary conditions on the TVSR can be effectively studied. The predicted results agreed well with existing experimental data using two classical boundary conditions: simply supported at all edges and clamped-free-free-free. The TVSR of a single panel with a more general boundary condition in two connected chambers was also measured. The predicted results agreed well with these experimental results. The prediction method was subsequently applied to evaluate the effects of elastic boundary supports on the TVSR of a window caused by a sonic boom. Loudness, non-audible acoustic perception, and tactile vibration thresholds were analyzed for different boundary conditions (varying between clamped and simply supported). The possibility of improving the transient vibration and noise isolation performance by selecting an appropriate boundary condition was thereby demonstrated. PMID:21877794

  2. Model experiment to study sonic boom propagation through turbulence. Part II. Effect of turbulence intensity and propagation distance through turbulence.

    PubMed

    Lipkens, B; Blackstock, D T

    1998-09-01

    A model experiment was reported to be successful in simulating the propagation of sonic booms through a turbulent atmosphere [B. Lipkens and D. T. Blackstock, J. Acoust. Soc. Am. 103, 148-158 (1998)]. In this study the effect on N wave characteristics of turbulence intensity and propagation distance through turbulence are investigated. The main parameters of interest are the rise time and the peak pressure. The effect of turbulence intensity and propagation distance is to flatten the rise time and peak pressure distributions. Rise time and peak pressure distributions always have positive skewness after propagation through turbulence. Average rise time grows with turbulence intensity and propagation distance. The scattering of rise time data is one-sided, i.e., rise times are almost always increased by turbulence. Average peak pressure decreases slowly with turbulence intensity and propagation distance. For the reported data a threefold increase in average rise time is observed and a maximum decrease of about 20% in average peak pressure. Rise times more than ten times that of the no turbulence value are observed. At most, the maximum peak pressure doubles after propagation through turbulence, and the minimum peak pressure values are about one-half the no-turbulence values. Rounded waveforms are always more common than peaked waveforms. PMID:9745733

  3. Wind Tunnel Model Design for the Study of Plume Effects on Sonic Boom for Isolated Exhaust Nozzles

    NASA Technical Reports Server (NTRS)

    Castner, Raynold S.

    2010-01-01

    A low cost test capability was developed at the NASA Glenn Research Center 1- by 1-Foot Supersonic Wind Tunnel (SWT), with a goal to reduce the disturbance caused by supersonic aircraft flight over populated areas. This work focused on the shock wave structure caused by the exhaust nozzle plume. Analysis and design was performed on a new rig to test exhaust nozzle plume effects on sonic boom signature. Test capability included a baseline nozzle test article and a wind tunnel model consisting of a strut, a nosecone and an upper plenum. Analysis was performed on the external and internal aerodynamic configuration, including the shock reflections from the wind tunnel walls caused by the presence of the model nosecone. This wind tunnel model was designed to operate from Mach 1.4 to Mach 3.0 with nozzle pressure ratios from 6 to 12 and altitudes from 30,000 ft (4.36 psia) to 50,000 ft (1.68 psia). The model design was based on a 1 in. outer diameter, was 9 in. in overall length, and was mounted in the wind tunnel on a 3/8 in. wide support strut. For test conditions at 50,000 ft the strut was built to supply 90 psia of pressure, and to achieve 20 psia at the nozzle inlet with a maximum nozzle pressure of 52 psia. Instrumentation was developed to measure nozzle pressure ratio, and an external static pressure probe was designed to survey near field static pressure profiles at one nozzle diameter above the rig centerline. Model layout placed test nozzles between two transparent sidewalls in the 1 1 SWT for Schlieren photography and comparison to CFD analysis.

  4. Wind Tunnel Model Design for the Study of Plume Effects on Sonic Boom for Isolated Exhaust Nozzles

    NASA Technical Reports Server (NTRS)

    Castner, Raymond S.

    2009-01-01

    A low cost test capability was developed at the NASA Glenn Research Center 1- by 1-Foot Supersonic Wind Tunnel (SWT), with a goal to reduce the disturbance caused by supersonic aircraft flight over populated areas. This work focused on the shock wave structure caused by the exhaust nozzle plume. Analysis and design was performed on a new rig to test exhaust nozzle plume effects on sonic boom signature. Test capability included a baseline nozzle test article and a wind tunnel model consisting of a strut, a nose cone and an upper plenum. Analysis was performed on the external and internal aerodynamic configuration, including the shock reflections from the wind tunnel walls caused by the presence of the model nosecone. This wind tunnel model was designed to operate from Mach 1.4 to Mach 3.0 with nozzle pressure ratios from 6 to 12 and altitudes from 30,000 ft (4.36 psia) to 50,000 ft (1.68 psia). The model design was based on a 1 in. outer diameter, was 9 in. in overall length, and was mounted in the wind tunnel on a 3/8 in. wide support strut. For test conditions at 50,000 ft the strut was built to supply 90 psia of pressure, and to achieve 20 psia at the nozzle inlet with a maximum nozzle pressure of 52 psia. Instrumentation was developed to measure nozzle pressure ratio, and an external static pressure probe was designed to survey near field static pressure profiles at one nozzle diameter above the rig centerline. Model layout placed test nozzles between two transparent sidewalls in the 1x1 SWT for Schlieren photography and comparison to CFD analysis.

  5. Wind-tunnel investigation of the validity of a sonic-boom-minimization concept. [Langley Unitary Plan Wind Tunnel tests for supersonic transport design

    NASA Technical Reports Server (NTRS)

    Mack, R. J.; Darden, C. M.

    1979-01-01

    The Langley unitary plan unitary plan wind tunnel was used to determine the validity of a sonic-boom-minimization theory. Five models - two reference and three low-boom constrained - were tested at design Mach numbers of 1.5 and 2.7. Results show that the pressure signatures generated by the low-boom models had significantly lower overpressure levels than those produced by the reference models and that small changes in the Mach number and/or the lift caused relatively small changes in the signature shape and overpressure level. Boundary-layer effects were found in the signature shape and overpressure level. Boundary-layer effects were found to be sizable on the low-boom models, and when viscous corrections were included in the analysis, improved agreement between the predicted and the measured signatures was noted. Since this agreement was better at Mach 1.5 than at Mach 2.7, it was concluded that the minimization method was definitely valid at Mach 1.5 and was probably valid at Mach 2.7, with further work needed to resolve the uncertainty.

  6. Model Deformation Measurements of Sonic Boom Models in the NASA Ames 9- by 7-Ft Supersonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Schairer, Edward T.; Kushner, Laura K.; Garbeff, Theodore J.; Heineck, James T.

    2015-01-01

    The deformations of two sonic-boom models were measured by stereo photogrammetry during tests in the 9- by 7-Ft Supersonic Wind Tunnel at NASA Ames Research Center. The models were geometrically similar but one was 2.75 times as large as the other. Deformation measurements were made by simultaneously imaging the upper surfaces of the models from two directions by calibrated cameras that were mounted behind windows of the test section. Bending and twist were measured at discrete points using conventional circular targets that had been marked along the leading and trailing edges of the wings and tails. In addition, continuous distributions of bending and twist were measured from ink speckles that had been applied to the upper surfaces of the model. Measurements were made at wind-on (M = 1.6) and wind-off conditions over a range of angles of attack between 2.5 deg. and 5.0 deg. At each condition, model deformation was determined by comparing the wind-off and wind-on coordinates of each measurement point after transforming the coordinates to reference coordinates tied to the model. The necessary transformations were determined by measuring the positions of a set of targets on the rigid center-body of the models whose model-axes coordinates were known. Smoothly varying bending and twist measurements were obtained at all conditions. Bending displacements increased in proportion to the square of the distance to the centerline. Maximum deflection of the wingtip of the larger model was about 5 mm (2% of the semispan) and that of the smaller model was 0.9 mm (1% of the semispan). The change in wing twist due to bending increased in direct proportion to distance from the centerline and reached a (absolute) maximum of about -1? at the highest angle of attack for both models. The measurements easily resolved bending displacements as small as 0.05 mm and bending-induced changes in twist as small as 0.05 deg.

  7. Conical Shock-Strength Determination on a Low-Sonic-Boom Aircraft Model by Doppler Global Velocimetry

    NASA Technical Reports Server (NTRS)

    Herring, Gregory C.; Meyers, James F.

    2011-01-01

    A nonintrusive technique Doppler global velocimetry (DGV) was used to determine conical shock strengths on a supersonic-cruise low-boom aircraft model. The work was performed at approximately Mach 2 in the Unitary Plan Wind Tunnel. Water is added to the wind tunnel flow circuit, generating small ice particles used as seed particles for the laser-based velocimetry. DGV generates two-dimensional (2-D) maps of three components of velocity that span the oblique shock. Shock strength (i.e. fractional pressure increase) is determined from observation of the flow deflection angle across the shock in combination with the standard shock relations. Although DGV had conveniently and accurately determined shock strengths from the homogenous velocity fields behind 2-D planar shocks, the inhomogeneous 3-D velocity fields behind the conical shocks presented additional challenges. Shock strength measurements for the near-field conical nose shock were demonstrated and compared with previously-published static pressure probe data for the same model in the same wind tunnel. Fair agreement was found between the two sets of results.

  8. Equivalent Longitudinal Area Distributions of the B-58 and XB-70-1 Airplanes for Use in Wave Drag and Sonic Boom Calculations

    NASA Technical Reports Server (NTRS)

    Tinetti, Ana F.; Maglieri, Domenic J.; Driver, Cornelius; Bobbitt, Percy J.

    2011-01-01

    A detailed geometric description, in wave drag format, has been developed for the Convair B-58 and North American XB-70-1 delta wing airplanes. These descriptions have been placed on electronic files, the contents of which are described in this paper They are intended for use in wave drag and sonic boom calculations. Included in the electronic file and in the present paper are photographs and 3-view drawings of the two airplanes, tabulated geometric descriptions of each vehicle and its components, and comparisons of the electronic file outputs with existing data. The comparisons include a pictorial of the two airplanes based on the present geometric descriptions, and cross-sectional area distributions for both the normal Mach cuts and oblique Mach cuts above and below the vehicles. Good correlation exists between the area distributions generated in the late 1950s and 1960s and the present files. The availability of these electronic files facilitates further validation of sonic boom prediction codes through the use of two existing data bases on these airplanes, which were acquired in the 1960s and have not been fully exploited.

  9. Measured Sonic Boom Signatures Above and Below the XB-70 Airplane Flying at Mach 1.5 and 37,000 Feet

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Henderson, Herbert R.; Tinetti, Ana F.

    2011-01-01

    During the 1966-67 Edwards Air Force Base (EAFB) National Sonic Boom Evaluation Program, a series of in-flight flow-field measurements were made above and below the USAF XB-70 using an instrumented NASA F-104 aircraft with a specially designed nose probe. These were accomplished in the three XB-70 flights at about Mach 1.5 at about 37,000 ft. and gross weights of about 350,000 lbs. Six supersonic passes with the F-104 probe aircraft were made through the XB-70 shock flow-field; one above and five below the XB-70. Separation distances ranged from about 3000 ft. above and 7000 ft. to the side of the XB-70 and about 2000 ft. and 5000 ft. below the XB-70. Complex near-field "sawtooth-type" signatures were observed in all cases. At ground level, the XB-70 shock waves had not coalesced into the two-shock classical sonic boom N-wave signature, but contained three shocks. Included in this report is a description of the generating and probe airplanes, the in-flight and ground pressure measuring instrumentation, the flight test procedure and aircraft positioning, surface and upper air weather observations, and the six in-flight pressure signatures from the three flights.

  10. Sonic Boom Research at NASA Dryden: Objectives and Flight Results from the Lift and Nozzle Change Effects on Tail Shock (LaNCETS) Project

    NASA Technical Reports Server (NTRS)

    Moes, Timothy R.

    2009-01-01

    The principal objective of the Supersonics Project is to develop and validate multidisciplinary physics-based predictive design, analysis and optimization capabilities for supersonic vehicles. For aircraft, the focus will be on eliminating the efficiency, environmental and performance barriers to practical supersonic flight. Previous flight projects found that a shaped sonic boom could propagate all the way to the ground (F-5 SSBD experiment) and validated design tools for forebody shape modifications (F-5 SSBD and Quiet Spike experiments). The current project, Lift and Nozzle Change Effects on Tail Shock (LaNCETS) seeks to obtain flight data to develop and validate design tools for low-boom tail shock modifications. Attempts will be made to alter the shock structure of NASA's NF-15B TN/837 by changing the lift distribution by biasing the canard positions, changing the plume shape by under- and over-expanding the nozzles, and changing the plume shape using thrust vectoring. Additional efforts will measure resulting shocks with a probing aircraft (F-15B TN/836) and use the results to validate and update predictive tools. Preliminary flight results are presented and are available to provide truth data for developing and validating the CFD tools required to design low-boom supersonic aircraft.

  11. Controlling the level of the sonic boom generated by a flying vehicle by means of cryogenic forcing. 3. Physical justification of the cryogenic action

    NASA Astrophysics Data System (ADS)

    Fomin, V. M.; Chirkashenko, V. F.; Volkov, V. F.; Kharitonov, A. M.

    2011-05-01

    The influence of the basic factors of cryogenic forcing on formation of the middle zone on the sonic boom and aerodynamic characteristics of the flying vehicle is studied by experimental and numerical methods. Experimental data obtained with alcohol or liquid nitrogen as an injected liquid are used for comparisons; as a result, the total effect of temperature and coolant evaporation can be determined. The influence of temperature is studied by means of numerical simulations of the cryogenic action of distributed injection of air. A comparison of numerical and experimental data reveals the effect of the coolant evaporation process on perturbed flow formation. It is demonstrated that evaporation of the coolant outgoing onto the vehicle surface should be intensified to increase the efficiency of cryogenic forcing (to decrease the coolant flow rate).

  12. An analysis of shock coalescence including three-dimensional effects with application to sonic boom extrapolation. Ph.D. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Darden, C. M.

    1984-01-01

    A method for analyzing shock coalescence which includes three dimensional effects was developed. The method is based on an extension of the axisymmetric solution, with asymmetric effects introduced through an additional set of governing equations, derived by taking the second circumferential derivative of the standard shock equations in the plane of symmetry. The coalescence method is consistent with and has been combined with a nonlinear sonic boom extrapolation program which is based on the method of characteristics. The extrapolation program, is able to extrapolate pressure signatures which include embedded shocks from an initial data line in the plane of symmetry at approximately one body length from the axis of the aircraft to the ground. The axisymmetric shock coalescence solution, the asymmetric shock coalescence solution, the method of incorporating these solutions into the extrapolation program, and the methods used to determine spatial derivatives needed in the coalescence solution are described. Results of the method are shown for a body of revolution at a small, positive angle of attack.

  13. An Analysis of Measured Pressure Signatures From Two Theory-Validation Low-Boom Models

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    2003-01-01

    Two wing/fuselage/nacelle/fin concepts were designed to check the validity and the applicability of sonic-boom minimization theory, sonic-boom analysis methods, and low-boom design methodology in use at the end of the 1980is. Models of these concepts were built, and the pressure signatures they generated were measured in the wind-tunnel. The results of these measurements lead to three conclusions: (1) the existing methods could adequately predict sonic-boom characteristics of wing/fuselage/fin(s) configurations if the equivalent area distributions of each component were smooth and continuous; (2) these methods needed revision so the engine-nacelle volume and the nacelle-wing interference lift disturbances could be accurately predicted; and (3) current nacelle-configuration integration methods had to be updated. With these changes in place, the existing sonic-boom analysis and minimization methods could be effectively applied to supersonic-cruise concepts for acceptable/tolerable sonic-boom overpressures during cruise.

  14. Responses of Raptorial Birds to Low Level Military Jets and Sonic Booms: Results of the 1980-1981 Joint U.S. Air Force-U.S. Fish and Wildlife Service Study

    USGS Publications Warehouse

    Ellis, D.H.

    1981-01-01

    Summary: For this study, we gathered several kinds of data to determine the likely effects of low level jets and sonic booms on nesting Peregrine Falcons and other raptors. We directly observed responses to worst case stimulus loads: responses to extremely frequent and extremely nearby jet aircraft were often minimal, seldom significant and never associated with reproductive failure. Likewise, responses to real and simulated sonic booms were often minimal and never productivity limiting. In addition to directly observing behavioral responses, in 1981 we invited jet passes at four Prairie Falcon eyries during courtship and incubation when the adults were most likely to abandon, on an ad libitum basis. All four eyries fledged young. Nesting success and site reoccupancy rates were high for all eyries. In tests of two relatively naive captive Peregrine Falcons, we failed to detect significantly negative responses. Typically the birds either quickly resumed feeding or other activities within a few seconds following a pass or boom. The female falcon repeatedly made hunting forays as jets swept overhead. From heart rate (HR) data taken via a telemetering egg during incubation at a wild Prairie Falcon eyrie, we determined that stimulus induced HR alterations were comparable to rate changes of the birds settling to incubate following flight. No significant long term responses were identified. The falcons successfully fledged two young even with the more disruptive activities associated with entering the eyrie three times to position and recover the telemetering eggs. Significantly, birds ofprey of several genera commonly nest in the supersonic military operations areas in southern Arizona. In addition, raptor eyries are frequently found at locations where low level jet traffic naturally concentrates. For example, Prairie Falcon Site 11 is directly on the approach path to strafing and bombing targets. Prairie Falcon Site 1 is in a narrow canyon through which A-10 aircraft

  15. Effects of aircraft noise and sonic booms on fish and wildlife: results of a survey of u. s. fish and wildlife service endangered species and ecological services field offices, refuges, hatcheries, and research centers

    SciTech Connect

    Gladwin, D.N.; Asherin, D.A.; Manci, K.M.

    1988-06-01

    The National Ecology Research Center (Center), as part of an ongoing research study on the effects of low-altitude aircraft operations on fish and wildlife, conducted a survey in January 1987 of all U.S. Fish and Wildlife Service (Service) regional directors, research center directors, Ecological Services and Endangered Species field offices supervisors, refuge manager, and hatchery manager. The objective of the survey was to determine the nature and extent of aircraft-induced impacts on fish and wildlife species, populations, and habitat utilization. The field-installation managers and biologists were asked to provide background information or data on fish and wildlife reactions to low-altitude aircraft disturbances, including physiological, behavioral, and reproductive/population effects. Specifically, the survey asked for information such as: observations pf amo,a; reaction(s) to aircraft operations, e.g., desert bighorn sheep scare behavior in response to aircraft overflights and hatchery fish seizures and death following intense sonic booms; and instances of areas where aircraft noise is known or believed to be responsible for reduced population size, e.g. areas along heavily used aircraft flight corridors where breeding waterfowl densities are lower than in similar habitat away from the noise area.

  16. Zip Boom

    NASA Technical Reports Server (NTRS)

    Swan, Scott; Smallcombe, Richard

    1995-01-01

    Lightweight deployable structural elements combined in stiff geometry. Three ribbons of spring material joined at edges to form triangular boom. Flexible case zips around extending boom to keep it triangular.

  17. Lateral Cutoff Analysis and Results from NASA's Farfield Investigation of No-Boom Thresholds

    NASA Technical Reports Server (NTRS)

    Cliatt, Larry J., II; Haering, Edward A., Jr.; Arnac, Sarah R.; Hill, Michael A.

    2016-01-01

    In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, the NASA Armstrong Flight Research Center (AFRC) and the NASA Langley Research Center (LaRC), in partnership with other industry organizations and academia, conducted a flight research experiment to analyze acoustic propagation at the lateral edge of the sonic boom carpet. The name of the effort was the Farfield Investigation of No-boom Thresholds (FaINT). The test helped to build a dataset that will go toward further understanding of the unique acoustic propagation characteristics near the sonic boom carpet extremity. The FaINT was an effort that collected finely-space sonic boom data across the entire lateral cutoff transition region. A major objective of the effort was to investigate the acoustic phenomena that occur at the audible edge of a sonic boom carpet, including the transition and shadow zones. A NASA F-18B aircraft made supersonic passes such that its sonic boom carpet transition zone would intersect a linear 60-microphone, 7500-ft long array. A TG-14 motor glider equipped with a microphone on its wing also attempted to capture the same sonic boom rays that were measured on the ground, at altitudes of 3000 - 6000 ft above ground level. This paper determined an appropriate metric for sonic boom waveforms in the transition and shadow zones called Perceived Sound Exposure Level, and established a value of 65 dB as a limit for the acoustic levels defining the lateral extent of a sonic boom's noise region; analyzed the change in sonic boom levels as a function of distance from flight path both on the ground and 4500 ft above the ground; and compared between sonic boom measurements and numerical predictions.

  18. What is that mysterious booming sound?

    USGS Publications Warehouse

    Hill, David P.

    2011-01-01

    The residents of coastal North Carolina are occasionally treated to sequences of booming sounds of unknown origin. The sounds are often energetic enough to rattle windows and doors. A recent sequence occurred in early January 2011 during clear weather with no evidence of local thunder storms. Queries by a local reporter (Colin Hackman of the NBC affiliate WETC in Wilmington, North Carolina, personal communication 2011) seemed to eliminate common anthropogenic sources such as sonic booms or quarry blasts. So the commonly asked question, “What's making these booming sounds?” remained (and remains) unanswered.

  19. A Summary of the Lateral Cutoff Analysis and Results from Nasa's Farfield Investigation of No-Boom Thresholds

    NASA Technical Reports Server (NTRS)

    Cliatt, Larry J., II; Hill, Michael A.; Haering, Edward A., Jr.; Arnac, Sarah R.

    2015-01-01

    In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, NASA, in partnership with other industry organizations, conducted a flight research experiment to analyze acoustic propagation at the lateral edge of the sonic boom carpet. The name of the effort was the Farfield Investigation of No-boom Thresholds (FaINT). The research from FaINT determined an appropriate metric for sonic boom waveforms in the transition and shadow zones called Perceived Sound Exposure Level, established a value of 65 dB as a limit for the acoustic lateral extent of a sonic boom's noise region, analyzed change in sonic boom levels near lateral cutoff, and compared between real sonic boom measurements and numerical predictions.

  20. A summary of the lateral cutoff analysis and results from NASA's Farfield Investigation of No-boom Thresholds

    NASA Astrophysics Data System (ADS)

    Cliatt, Larry J.; Hill, Michael A.; Haering, Edward A.; Arnac, Sarah R.

    2015-10-01

    In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, NASA, in partnership with other industry organizations, conducted a flight research experiment to analyze acoustic propagation at the lateral edge of the sonic boom carpet. The name of the effort was the Farfield Investigation of No-boom Thresholds (FaINT). The research from FaINT determined an appropriate metric for sonic boom waveforms in the transition and shadow zones called Perceived Sound Exposure Level, established a value of 65 dB as a limit for the acoustic lateral extent of a sonic boom's noise region, analyzed change in sonic boom levels near lateral cutoff, and compared between real sonic boom measurements and numerical predictions.

  1. [Changes of pulse rate caused by sonic bomms during sleep (author's transl)].

    PubMed

    Griefahn, B

    1975-12-01

    In two experimental series (19 resp. 53 nights, 2 different persons in each series, test-time 10.30 p.m. to 3.00 a.m.) pulse rate after sonic booms had been recorded during sleep. In the first 3 nights the subjects slept undisturbed by noise. In the following 11 resp. 30 nights sonic booms were applied alternately 2 or 4 times. In the main series after 10 more nights without any noise 4 nights with 8 and 16 sonic booms alternately followed. The last 6 undisturbed nights in both series were used as comparison phase. The interval between two sonic booms was 40 min in nights with 2 booms, 20 min in nights with 4 sonic booms and in the nights with 8 and 16 sonic booms 8.6 resp. 4.6 min. Sound level of the sonic booms ranged from 0.48 mbar to 1.45 mbar, 1 mbar [83.5 dB (A)] in the average. The first sonic boom was applied if one of the two subjects had entered the deepest stage of sleep. Sonic booms induced a biphasic reaction in pulse rate. After an initial increase in frequency with a maximum in the 4th sec pulse rate decreased below the value before sonic boom; it was followed by a slow increase towards the baseline value. This reaction was analysed with special regard to the following factors: 1. Intensity. Due to very fast increase of noise intensity there was no significant correlation between the intensity of sonic boom and the pulse reaction. 2. Exogenic variables. There is no significant connection between postboom pulse rate and noiseless time before the sonic boom, the duration of the test series and the ambient temperature. 3. Endogenic variables. No correlation could be found between the stage of sleep and the reaction. On the contrary a very significant correlation was found between the maximum of postboom increase of pulse rate and the pulse rate before boom. With increasing pulse rate the extent of reaction becomes smaller. PMID:1201745

  2. Sonic Watermarking

    NASA Astrophysics Data System (ADS)

    Tachibana, Ryuki

    2004-12-01

    Audio watermarking has been used mainly for digital sound. In this paper, we extend the range of its applications to live performances with a new composition method for real-time audio watermarking. Sonic watermarking mixes the sound of the watermark signal and the host sound in the air to detect illegal music recordings recorded from auditoriums. We propose an audio watermarking algorithm for sonic watermarking that increases the magnitudes of the host signal only in segmented areas pseudorandomly chosen in the time-frequency plane. The result of a MUSHRA subjective listening test assesses the acoustic quality of the method in the range of "excellent quality." The robustness is dependent on the type of music samples. For popular and orchestral music, a watermark can be stably detected from music samples that have been sonic-watermarked and then once compressed in an MPEG[InlineEquation not available: see fulltext.] layer[InlineEquation not available: see fulltext.] file.

  3. Boom-Constrained Drag Minimization for Design of Supersonic Concepts

    NASA Technical Reports Server (NTRS)

    Rallabhandi, Sriram K.; Li, Wu; Geiselhart, Karl

    2010-01-01

    This paper presents an approach to modifying an existing baseline configuration that has been designed to achieve low-boom characteristics in order to minimize drag while not severely penalizing baseline sonic boom levels. The baseline configuration that was used is the result of using a mixed-fidelity CFD-based low-boom design process that has been tested and verified. Shape modifications are carried out by using arbitrary shape-deformation algorithms. The focus of this paper is the integration of several key enabling techniques and methods for efficient redesign under stringent constraints.

  4. A Grid Sourcing and Adaptation Study Using Unstructured Grids for Supersonic Boom Prediction

    NASA Technical Reports Server (NTRS)

    Carter, Melissa B.; Deere, Karen A.

    2008-01-01

    NASA created the Supersonics Project as part of the NASA Fundamental Aeronautics Program to advance technology that will make a supersonic flight over land viable. Computational flow solvers have lacked the ability to accurately predict sonic boom from the near to far field. The focus of this investigation was to establish gridding and adaptation techniques to predict near-to-mid-field (<10 body lengths below the aircraft) boom signatures at supersonic speeds using the USM3D unstructured grid flow solver. The study began by examining sources along the body the aircraft, far field sourcing and far field boundaries. The study then examined several techniques for grid adaptation. During the course of the study, volume sourcing was introduced as a new way to source grids using the grid generation code VGRID. Two different methods of using the volume sources were examined. The first method, based on manual insertion of the numerous volume sources, made great improvements in the prediction capability of USM3D for boom signatures. The second method (SSGRID), which uses an a priori adaptation approach to stretch and shear the original unstructured grid to align the grid and pressure waves, showed similar results with a more automated approach. Due to SSGRID s results and ease of use, the rest of the study focused on developing a best practice using SSGRID. The best practice created by this study for boom predictions using the CFD code USM3D involved: 1) creating a small cylindrical outer boundary either 1 or 2 body lengths in diameter (depending on how far below the aircraft the boom prediction is required), 2) using a single volume source under the aircraft, and 3) using SSGRID to stretch and shear the grid to the desired length.

  5. New western boom towns

    SciTech Connect

    Daneke, G.A.

    1980-09-30

    The Mountain West, particularly isolated rural communities, can expect rapid growth which cannot be accurately predicted by the usual population-forecasting techniques. Mining and defense projects, combined with a general population shift to the South and West, have already brought some anticipatory migration to areas that have not prepared an infrastructure to handle the social and economic demands of boom towns. The relationship between meeting the physical and human needs of a community are poorly understood, with the result that most local planners concentrate on the water, sewer, and street planning of traditional urban-sprawl patterns and contribute to community disintegration. A carefully planned infrastructure which incorporates social-service planning could anticipate many problems and introduce innovative environmental and energy-saving ideas. (DCK)

  6. GEOS axial booms

    NASA Technical Reports Server (NTRS)

    Schmidt, G. K.

    1979-01-01

    A booms and mechanisms subsystem was designed, developed, and qualified for the geostationary scientific satellite GEOS. Part of this subsystem consist of four axial booms consisting of one pair of 1 m booms and one pair of 2.5 m booms. Each of these booms is carrying one bird cage electric field sensor. Alignment accuracy requirements led to a telescopic type solution. Deployment is performed by pressurized nitrogen. At deployment in orbit two of these booms showed some anomalies and one of these two deployed only about 80%. Following this malfunction a detailed failure investigation was performed resulting in a design modification of some critical components as release mechanism, guide sleeves of the telescopic elements, and pressure system.

  7. Buffaloed by the energy boom

    SciTech Connect

    Morris, R.

    1981-11-01

    The western energy boom is producing the mineral wealth to restore the US economy and security as well as producing boom towns that should be getting more media and public attention. Accurate and more sensitive journalism is needed to record what is happening in the Rocky Mountain region beyond the headlines of confrontations and boosterism. The case of uranium mining and milling is one of a long cycle of land acquisition and development, but it produced little historical record until incidents happened and charges of negligence were made. There is no shortage of material for reporters who want to cover the story of strip mining, water resources, and other issues, but the public must appreciate the life cycle of a mine before it can fully grasp the significance of individual events. This requires aggressive and independent news gathering and sustained coverage. (DCK)

  8. Echo Boom Impact

    ERIC Educational Resources Information Center

    Dordai, Phillipe; Rizzo, Joseph

    2006-01-01

    Like their baby-boomer parents, the echo-boom generation is reshaping the college and university landscape. At 80 million strong, this group of children and young adults born between 1980 and 1995 now is flooding the college and university system, spurring a college building boom. According to Campus Space Crunch, a Hillier Architecture survey of…

  9. HYDRODYNAMICS OF DIVERSIONARY BOOMS

    EPA Science Inventory

    The failure of booms to contain floating oil in currents above 0.5 m/s appears to be well established. A method suggested to surmount this limitation is to use the boom in a diversionary mode to move the oil into regions of low currents where containment and removal can be accomp...

  10. Oil containment booms

    SciTech Connect

    Teasdale, R.G.

    1982-04-20

    A design of an oil containment boom suitable particularly for stowage on a reel is disclosed. The boom, in its inflated condition, is of ''t'' section having double buoyancy chambers and a central skirt member. The boom utilizes a tension wire in its lower skirt region and an air pressurizing hose in its upper skirt region above the buoyancy chambers. The geometry of the panels making up the chambers is arranged, together with the joints, to give a substantially flat deflated form. The air pressurizing hose and the tension wire are of comparable diameter each being of larger diameter than the maximum thickness of the deflated boom whereby undesirable folding and puckering of the boom material when wound up is accommodated in the lateral space between the hose and the wire.

  11. Oil containment booms

    SciTech Connect

    Teasdale, R.G.

    1983-09-13

    The invention concerns the design of an oil containment boom suitable particularly for stowage on a reel. The boom in its inflated condition, is of ''T'' section having double buoyancy chambers and a central skirt member. The boom utilizes a tension wire in its lower skirt region and an air pressurizing hose in its upper skirt above the buoyancy chambers. The geometry of the panels making up the chambers is arranged, together with the joints, to give a substantially flat deflated form. The air pressurizing hose and the tension wire are of comparable diameter each being of larger diameter than the maximum thickness of the deflated boom whereby undesirable folding and puckering of the boom material when wound up is accommodated in the lateral space between the hose and the wire.

  12. Boom Minimization Framework for Supersonic Aircraft Using CFD Analysis

    NASA Technical Reports Server (NTRS)

    Ordaz, Irian; Rallabhandi, Sriram K.

    2010-01-01

    A new framework is presented for shape optimization using analytical shape functions and high-fidelity computational fluid dynamics (CFD) via Cart3D. The focus of the paper is the system-level integration of several key enabling analysis tools and automation methods to perform shape optimization and reduce sonic boom footprint. A boom mitigation case study subject to performance, stability and geometrical requirements is presented to demonstrate a subset of the capabilities of the framework. Lastly, a design space exploration is carried out to assess the key parameters and constraints driving the design.

  13. Booming Sand Dunes

    NASA Astrophysics Data System (ADS)

    Vriend, Nathalie

    "Booming" sand dunes are able to produce low-frequency sound that resembles a pure note from a music instrument. The sound has a dominant audible frequency (70-105 Hz) and several higher harmonics and may be heard from far distances away. A natural or induced avalanche from a slip face of the booming dune triggers the emission that may last for several minutes. There are various references in travel literature to the phenomenon, but to date no scientific explanation covered all field observations. This thesis introduces a new physical model that describes the phenomenon of booming dunes. The waveguide model explains the selection of the booming frequency and the amplification of the sound in terms of constructive interference in a confined geometry. The frequency of the booming is a direct function of the dimensions and velocities in the waveguide. The higher harmonics are related to the higher modes of propagation in the waveguide. The experimental validation includes quantitative field research at the booming dunes of the Mojave Desert and Death Valley National Park. Microphone and geophone recordings of the acoustic and seismic emission show a variation of booming frequency in space and time. The analysis of the sensor data quantifies wave propagation characteristics such as speed, dispersion, and nonlinear effects and allows the distinction between the source mechanism of the booming and the booming itself. The migration of sand dunes results from a complicated interplay between dune building, wind regime, and precipitation. The morphological and morphodynamical characteristics of two field locations are analyzed with various geophysical techniques. Ground-penetrating radar images the subsurface structure of the dunes and reveal a natural, internal layering that is directly related to the history of dune migration. The seismic velocity increases abruptly with depth and gradually increases with downhill position due to compaction. Sand sampling shows local

  14. Aerodynamic Effects of a 24-foot Multisegmented Telescoping Nose Boom on an F-15B Airplane

    NASA Technical Reports Server (NTRS)

    Cumming, Stephen B.; Smith, Mark S.; Frederick, Michael A.

    2008-01-01

    An experimental multisegmented telescoping nose boom has been installed on an F-15B airplane to be tested in a flight environment. The experimental nose boom is representative of one that could be used to tailor the sonic boom signature of an airplane such as a supersonic business jet. The nose boom consists of multiple sections and could be extended during flight to a length of 24 ft. The preliminary analyses indicate that the addition of the experimental nose boom could adversely affect vehicle flight characteristics and air data systems. Before the boom was added, a series of flights was conducted to update the aerodynamic model and characterize the air data systems of the baseline airplane. The baseline results have been used in conjunction with estimates of the nose boom's influence to prepare for a series of research flights conducted with the nose boom installed. Data from these flights indicate that the presence of the experimental boom reduced the static pitch and yaw stability of the airplane. The boom also adversely affected the static-position error of the airplane but did not significantly affect angle-of-attack or angle-of-sideslip measurements. The research flight series has been successfully completed.

  15. Aerodynamic Effects of a 24-Foot, Multisegmented Telescoping Nose Boom on an F-15B Airplane

    NASA Technical Reports Server (NTRS)

    Cumming, Stephen B.; Smith, Mark S.; Frederick, Michael A.

    2007-01-01

    An experimental multisegmented telescoping nose boom has been installed on an F-15B airplane to be tested in a flight environment. The experimental nose boom is representative of one that could be used to tailor the sonic boom signature of an airplane such as a supersonic business jet. The nose boom consists of multiple sections and could be extended during flight to a length of 24 ft. The preliminary analyses indicated that the addition of the experimental nose boom could adversely affect vehicle flight characteristics and air data systems. Before the boom was added, a series of flights was flown to update the aerodynamic model and characterize the air data systems of the baseline airplane. The baseline results have been used in conjunction with estimates of the nose boom s influence to prepare for a series of research flights conducted with the nose boom installed. Data from these flights indicate that the presence of the experimental boom reduced the static pitch and yaw stability of the airplane. The boom also adversely affected the static-position error of the airplane but did not significantly affect angle-of-attack or angle-of-sideslip measurements. The research flight series has been successfully completed.

  16. Sonic boom focal zones due to tactical aircraft maneuvers

    NASA Astrophysics Data System (ADS)

    Plotkin, Kenneth J.

    1990-10-01

    A study has been conducted of the focal zone 'superbooms' associated with tactical maneuvers of military supersonic aircraft. Focal zone footprints were computed for 21 tactical maneuvers: two for the SR-71 and 19 for fighters engaged in air combat maneuver (ACM) training. These footprints provide quantitative results which may be used for environmental planning. A key finding of this study is that focus factors and footprint areas for high-g fighter maneuvers are substantially smaller than those for gentle maneuvers associated with larger aircraft.

  17. The Voyager magnetometer boom

    NASA Technical Reports Server (NTRS)

    Miller, D. C.

    1979-01-01

    The Voyager spacecraft magnetometer experiment utilizes two sensors on a deployable boom. The boom is an Astromast. The implementation of the Astromast into the Voyager design is described along with the hardware used to hold, latch, and deploy the mast and the tests to demonstrate damping, deployment, and alignments. Several problems encountered are discussed and their solutions are given. Flight deployment and preliminary alignment results are presented. Finally, the design is evaluated in retrospect.

  18. Some considerations on the integration of engine nacelles into low-boom aircraft concepts

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    1992-01-01

    A study of wind-tunnel data has shown why unexpected strong shock waves appeared in wind tunnel pressure signatures of two low-boom models, and has indicated that changes to the current methods for analyzing and designing low-boom aircraft are needed. The discussion provided corrections for the interface lift code, and suggested methods of treatment for the equivalent areas of the aircraft, especially the nacelles and the interference lift, which were to be used in the aircraft design and the sonic boom analysis.

  19. Generation of Parametric Equivalent-Area Targets for Design of Low-Boom Supersonic Concepts

    NASA Technical Reports Server (NTRS)

    Li, Wu; Shields, Elwood

    2011-01-01

    A tool with an Excel visual interface is developed to generate equivalent-area (A(sub e)) targets that satisfy the volume constraints for a low-boom supersonic configuration. The new parametric Ae target explorer allows users to interactively study the tradeoffs between the aircraft volume constraints and the low-boom characteristics (e.g., loudness) of the ground signature. Moreover, numerical optimization can be used to generate the optimal A(sub e) target for given A(sub e) volume constraints. A case study is used to demonstrate how a generated low-boom Ae target can be matched by a supersonic configuration that includes a fuselage, wing, nacelle, pylon, aft pod, horizontal tail, and vertical tail. The low-boom configuration is verified by sonic-boom analysis with an off-body pressure distribution at three body lengths below the configuration

  20. Ultrasonic/Sonic Anchor

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Sherrit, Stewart

    2009-01-01

    The ultrasonic/sonic anchor (U/S anchor) is an anchoring device that drills a hole for itself in rock, concrete, or other similar material. The U/S anchor is a recent addition to a series of related devices, the first of which were reported in "Ultrasonic/Sonic Drill/Corers With Integrated Sensors"

  1. The Prep School Boom

    ERIC Educational Resources Information Center

    Stent, Angela

    1976-01-01

    Applications to preparatory schools have risen dramatically in the past five years, as much as 500 percent at some prestigious institutions. Most educators agree that the main reason for this boom is the growing disenchantment with vast, anomic public high schools, both urban and suburban. (LBH)

  2. STANDARDIZING BOOM TEST PROCEDURES

    EPA Science Inventory

    The OHMSETT Interagency Technical Committee (OTIC) sponsored a combined series of in-tank and open-water tests of five booms that cover a wide range of sizes and design parameters. The tests were conducted at the United States Environmental Protection Agency's OHMSETT facility an...

  3. Sonic spectrometer and treatment system

    DOEpatents

    Slomka, Bogdan J.

    1997-06-03

    A novel system and method for treating an object with sonic waveforms. A traveling broad-band sonic waveform containing a broad-band of sonic frequencies is radiated at the object. A traveling reflected sonic waveform containing sonic frequencies reflected by the object is received in response to the traveling broad-band sonic waveform. A traveling transmitted sonic waveform containing sonic frequencies transmitted through the object is also received in response to the traveling broad-band sonic waveform. In a resonance mode, the frequency spectra of the broad-band and reflected sonic waveforms is analyzed so as to select one or more sonic frequencies that cause the object to resonate. An electrical resonance treatment sonic waveform containing the sonic frequencies that cause the object to resonate is then radiated at the object so as to treat the object. In an absorption mode, the frequency spectra of the electrical broad-band, reflected, and transmitted sonic waveforms is compared so as to select one or more sonic frequencies that are absorbed by the object. An electrical absorption treatment sonic waveform containing the sonic frequencies that are absorbed by the object is then radiated at the object so as to treat the object.

  4. Sonic spectrometer and treatment system

    DOEpatents

    Slomka, B.J.

    1997-06-03

    A novel system and method is developed for treating an object with sonic waveforms. A traveling broad-band sonic waveform containing a broad-band of sonic frequencies is radiated at the object. A traveling reflected sonic waveform containing sonic frequencies reflected by the object is received in response to the traveling broad-band sonic waveform. A traveling transmitted sonic waveform containing sonic frequencies transmitted through the object is also received in response to the traveling broad-band sonic waveform. In a resonance mode, the frequency spectra of the broad-band and reflected sonic waveforms is analyzed so as to select one or more sonic frequencies that cause the object to resonate. An electrical resonance treatment sonic waveform containing the sonic frequencies that cause the object to resonate is then radiated at the object so as to treat the object. In an absorption mode, the frequency spectra of the electrical broad-band, reflected, and transmitted sonic waveforms is compared so as to select one or more sonic frequencies that are absorbed by the object. An electrical absorption treatment sonic waveform containing the sonic frequencies that are absorbed by the object is then radiated at the object so as to treat the object. 1 fig.

  5. Doppler effect induced spin relaxation boom.

    PubMed

    Zhao, Xinyu; Huang, Peihao; Hu, Xuedong

    2016-01-01

    We study an electron spin qubit confined in a moving quantum dot (QD), with our attention on both spin relaxation, and the product of spin relaxation, the emitted phonons. We find that Doppler effect leads to several interesting phenomena. In particular, spin relaxation rate peaks when the QD motion is in the transonic regime, which we term a spin relaxation boom in analogy to the classical sonic boom. This peak indicates that a moving spin qubit may have even lower relaxation rate than a static qubit, pointing at the possibility of coherence-preserving transport for a spin qubit. We also find that the emitted phonons become strongly directional and narrow in their frequency range as the qubit reaches the supersonic regime, similar to Cherenkov radiation. In other words, fast moving excited spin qubits can act as a source of non-classical phonons. Compared to classical Cherenkov radiation, we show that quantum dot confinement produces a small but important correction on the Cherenkov angle. Taking together, these results have important implications to both spin-based quantum information processing and coherent phonon dynamics in semiconductor nanostructures. PMID:26996253

  6. Doppler effect induced spin relaxation boom

    PubMed Central

    Zhao, Xinyu; Huang, Peihao; Hu, Xuedong

    2016-01-01

    We study an electron spin qubit confined in a moving quantum dot (QD), with our attention on both spin relaxation, and the product of spin relaxation, the emitted phonons. We find that Doppler effect leads to several interesting phenomena. In particular, spin relaxation rate peaks when the QD motion is in the transonic regime, which we term a spin relaxation boom in analogy to the classical sonic boom. This peak indicates that a moving spin qubit may have even lower relaxation rate than a static qubit, pointing at the possibility of coherence-preserving transport for a spin qubit. We also find that the emitted phonons become strongly directional and narrow in their frequency range as the qubit reaches the supersonic regime, similar to Cherenkov radiation. In other words, fast moving excited spin qubits can act as a source of non-classical phonons. Compared to classical Cherenkov radiation, we show that quantum dot confinement produces a small but important correction on the Cherenkov angle. Taking together, these results have important implications to both spin-based quantum information processing and coherent phonon dynamics in semiconductor nanostructures. PMID:26996253

  7. Doppler effect induced spin relaxation boom

    NASA Astrophysics Data System (ADS)

    Zhao, Xinyu; Huang, Peihao; Hu, Xuedong

    2016-03-01

    We study an electron spin qubit confined in a moving quantum dot (QD), with our attention on both spin relaxation, and the product of spin relaxation, the emitted phonons. We find that Doppler effect leads to several interesting phenomena. In particular, spin relaxation rate peaks when the QD motion is in the transonic regime, which we term a spin relaxation boom in analogy to the classical sonic boom. This peak indicates that a moving spin qubit may have even lower relaxation rate than a static qubit, pointing at the possibility of coherence-preserving transport for a spin qubit. We also find that the emitted phonons become strongly directional and narrow in their frequency range as the qubit reaches the supersonic regime, similar to Cherenkov radiation. In other words, fast moving excited spin qubits can act as a source of non-classical phonons. Compared to classical Cherenkov radiation, we show that quantum dot confinement produces a small but important correction on the Cherenkov angle. Taking together, these results have important implications to both spin-based quantum information processing and coherent phonon dynamics in semiconductor nanostructures.

  8. Measurement of turbulent wind velocities using a rotating boom apparatus

    SciTech Connect

    Sandborn, V.A.; Connell, J.R.

    1984-04-01

    The present report covers both the development of a rotating-boom facility and the evaluation of the spectral energy of the turbulence measured relative to the rotating boom. The rotating boom is composed of a helicopter blade driven through a pulley speed reducer by a variable speed motor. The boom is mounted on a semiportable tower that can be raised to provide various ratios of hub height to rotor diameter. The boom can be mounted to rotate in either the vertical or horizontal plane. Probes that measure the three components of turbulence can be mounted at any location along the radius of the boom. Special hot-film sensors measured two components of the turbulence at a point directly in front of the rotating blade. By using the probe rotated 90/sup 0/ about its axis, the third turbulent velocity component was measured. Evaluation of the spectral energy distributions for the three components of velocity indicates a large concentration of energy at the rotational frequency. At frequencies slightly below the rotational frequency, the spectral energy is greatly reduced over that measured for the nonrotating case measurements. Peaks in the energy at frequencies that are multiples of the rotation frequency were also observed. We conclude that the rotating boom apparatus is suitable and ready to be used in experiments for developing and testing sensors for rotational measurement of wind velocity from wind turbine rotors. It also can be used to accurately measure turbulent wind for testing theories of rotationally sampled wind velocity.

  9. The next boom

    SciTech Connect

    Gipe, P.

    1995-02-01

    In 1994, global windpower projects generated electricity valued at nearly $500 million. The 3,400 MW installed worldwide is split about evenly between the United States and Europe. Windpower`s growth continues as more companies expand and upgrade their product lines while pursuing broader markets. If capacity continues its upward growth - with the potential to double by 2000 - the remainder of the decade may look like the 1980s windpower boom.

  10. A Mixed-Fidelity Approach for Design of Low-Boom Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Li, Wu; Shields, Elwood; Geiselhart, Karl A.

    2010-01-01

    This paper documents a mixed-fidelity approach for the design of low-boom supersonic aircraft as a viable approach for designing a practical low-boom supersonic configuration. A low-boom configuration that is based on low-fidelity analysis is used as the baseline. Tail lift is included to help tailor the aft portion of the ground signature. A comparison of low- and high-fidelity analysis results demonstrates the necessity of using computational fluid dynamics (CFD) analysis in a low-boom supersonic configuration design process. The fuselage shape is modified iteratively to obtain a configuration with a CFD equivalent-area distribution that matches a predetermined low-boom target distribution. The mixed-fidelity approach can easily refine the low-fidelity low-boom baseline into a low-boom configuration with the use of CFD equivalent-area analysis. The ground signature of the final configuration is calculated by using a state-of-the-art CFD-based boom analysis method that generates accurate midfield pressure distributions for propagation to the ground with ray tracing. The ground signature that is propagated from a midfield pressure distribution has a shaped ramp front, which is similar to the ground signature that is propagated from the CFD equivalent-area distribution. This result confirms the validity of the low-boom supersonic configuration design by matching a low-boom equivalent-area target, which is easier to accomplish than matching a low-boom midfield pressure target.

  11. Sonic Thermometer for High-Altitude Balloons

    NASA Technical Reports Server (NTRS)

    Bognar, John

    2012-01-01

    The sonic thermometer is a specialized application of well-known sonic anemometer technology. Adaptations have been made to the circuit, including the addition of supporting sensors, which enable its use in the high-altitude environment and in non-air gas mixtures. There is a need to measure gas temperatures inside and outside of superpressure balloons that are flown at high altitudes. These measurements will allow the performance of the balloon to be modeled more accurately, leading to better flight performance. Small thermistors (solid-state temperature sensors) have been used for this general purpose, and for temperature measurements on radiosondes. A disadvantage to thermistors and other physical (as distinct from sonic) temperature sensors is that they are subject to solar heating errors when they are exposed to the Sun, and this leads to issues with their use in a very high-altitude environment

  12. A precision six-meter deployable boom for the Mariner-Venus-Mercury 1973 magnetometer experiment

    NASA Technical Reports Server (NTRS)

    Burdick, H. F.

    1975-01-01

    A unique deployable boom developed for accurately positioning magnetometers 6 meters (19.7 feet) from a spacecraft is described. Weight, mounting system, magnetic cleanliness, thermal dimensional stability, and natural frequency were critical constraints that were met. The boom was flown on Mariner 10 and deployed flawlessly. The design, development, and testing of the boom and optical alignment of the sensors are described. Design trades and problem solutions are discussed.

  13. Ultrasonic/Sonic Jackhammer

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Sherrit, Stewart; Herz, Jack

    2005-01-01

    An ultrasonic/sonic jackhammer (USJ) is the latest in a series of related devices. Each of these devices cuts into a brittle material by means of hammering and chiseling actions of a tool bit excited with a combination of ultrasonic and sonic vibrations. A small-scale prototype of the USJ has been demonstrated. A fully developed, full-scale version of the USJ would be used for cutting through concrete, rocks, hard asphalt, and other materials to which conventional pneumatic jackhammers are applied, but the USJ would offer several advantages over conventional pneumatic jackhammers.

  14. Full-Carpet Design of a Low-Boom Demonstrator Concept

    NASA Technical Reports Server (NTRS)

    Ordaz, Irian; Wintzer, Mathias; Rallabhandi, Sriram K.

    2015-01-01

    The Cart3D adjoint-based design framework is used to mitigate the undesirable o -track sonic boom properties of a demonstrator concept designed for low-boom directly under the flight path. First, the requirements of a Cart3D design mesh are determined using a high-fidelity mesh adapted to minimize the discretization error of the CFD analysis. Low-boom equivalent area targets are then generated at the under-track and one off-track azimuthal position for the baseline configuration. The under-track target is generated using a trim- feasible low-boom target generation process, ensuring that the final design is not only low-boom, but also trimmed at the specified flight condition. The o -track equivalent area target is generated by minimizing the A-weighted loudness using an efficient adjoint-based approach. The configuration outer mold line is then parameterized and optimized to match the off-body pressure distributions prescribed by the low-boom targets. The numerical optimizer uses design gradients which are calculated using the Cart3D adjoint- based design capability. Optimization constraints are placed on the geometry to satisfy structural feasibility. The low-boom properties of the final design are verified using the adaptive meshing approach. This analysis quantifies the error associated with the CFD mesh that is used for design. Finally, an alternate mesh construction and target positioning approach offering greater computational efficiency is demonstrated and verified.

  15. A wing design methodology for low-boom low-drag supersonic business jet

    NASA Astrophysics Data System (ADS)

    Le, Daniel B.

    2009-12-01

    The arguably most critical hindrance to the successful development of a commercial supersonic aircraft is the impact of the sonic boom signature. The sonic boom signature of a supersonic aircraft is predicted using sonic boom theory, which formulates a relationship between the complex three-dimensional geometry of the aircraft to the pressure distribution and decomposes the geometry in terms of simple geometrical components. The supersonic aircraft design process is typically based on boom minimization theory. This theory provides a theoretical equivalent area distribution which should be matched by the conceptual design in order to achieve the pre-determined sonic boom signature. The difference between the target equivalent area distribution and the actual equivalent area distribution is referred to here as the gap distribution. The primary intent of this dissertation is to provide the designer with a systematic and structured approach to designing the aircraft wings with limited changes to the baseline concept while achieving critical design goals. The design process can be easily overwhelmed and may be difficult to evaluate their effectiveness. The wing design is decoupled into two separate processes, one focused on the planform design and the other on the camber design. Moreover, this design methodology supplements the designer by allowing trade studies to be conducted between important design parameters and objectives. The wing planform design methodology incorporates a continuous gradient-based optimization scheme to supplement the design process. This is not meant to substitute the vast amount of knowledge and design decisions that are needed for a successful design. Instead, the numerical optimization helps the designer to refine creative concepts. Last, this dissertation integrates a risk mitigation scheme throughout the wing design process. The design methodology implements minimal design changes to the wing geometry white achieving the target design goal

  16. The Galeleo spacecraft magnetometer boom

    NASA Technical Reports Server (NTRS)

    Packard, D. T.; Benton, M. D.

    1985-01-01

    The Galileo spacecraft utilizes a deployable lattice boom to position three science instruments at remote distances from the spacecraft body. An improved structure and mechanism to precisely control deployment of the boom, and the unique deployment of an outer protective cover are described.

  17. Test temperature compensated gas meters with sonic nozzles

    SciTech Connect

    Giglio, P.F.

    1983-01-01

    Explains how a sonic nozzle test facility gives accurate, repeatable results in all temperatures. Niagara Mohawk Power Corp., in late 1963, made a decision to introduce the temperature compensated gas meter into their system to facilitate outdoor meter locations. The test facility was constructed utilizing a water and ethylene glycol bath to condition the gas meter and test medium (air) to the nominal temperature requirements. Sonic nozzles produced extremely repeatable test results from the very beginning. Meter testing time could be considerably reduced due to the inherent repeatability of the sonic nozzles and the simplicity of accurately measuring time, temperature and the relative humidity of the test medium. The sonic nozzles were connected to the outlet of the bell prover with their inlet facing the bell prover side of the connection. A vacuum source was then connected to the outlet side of the sonic nozzle to provide the differential pressure necessary to achieve sonic flow. Based on the test results it was decided to utilize 3-psi vacuum for the calibration of the sonic nozzles.

  18. Inverse Design of Low-Boom Supersonic Concepts Using Reversed Equivalent-Area Targets

    NASA Technical Reports Server (NTRS)

    Li, Wu; Rallabhand, Sriam

    2011-01-01

    A promising path for developing a low-boom configuration is a multifidelity approach that (1) starts from a low-fidelity low-boom design, (2) refines the low-fidelity design with computational fluid dynamics (CFD) equivalent-area (Ae) analysis, and (3) improves the design with sonic-boom analysis by using CFD off-body pressure distributions. The focus of this paper is on the third step of this approach, in which the design is improved with sonic-boom analysis through the use of CFD calculations. A new inverse design process for off-body pressure tailoring is formulated and demonstrated with a low-boom supersonic configuration that was developed by using the mixed-fidelity design method with CFD Ae analysis. The new inverse design process uses the reverse propagation of the pressure distribution (dp/p) from a mid-field location to a near-field location, converts the near-field dp/p into an equivalent-area distribution, generates a low-boom target for the reversed equivalent area (Ae,r) of the configuration, and modifies the configuration to minimize the differences between the configuration s Ae,r and the low-boom target. The new inverse design process is used to modify a supersonic demonstrator concept for a cruise Mach number of 1.6 and a cruise weight of 30,000 lb. The modified configuration has a fully shaped ground signature that has a perceived loudness (PLdB) value of 78.5, while the original configuration has a partially shaped aft signature with a PLdB of 82.3.

  19. Low-Boom and Low-Drag Optimization of the Twin Engine Version of Silent Supersonic Business Jet

    NASA Astrophysics Data System (ADS)

    Sato, Koma; Kumano, Takayasu; Yonezawa, Masahito; Yamashita, Hiroshi; Jeong, Shinkyu; Obayashi, Shigeru

    Multi-Objective Optimization has been applied to a design problem of the twin engine concept for Silent Supersonic Business Jet (SSBJ). This problem aims to find main wing, body, tail wing and engine nacelle configurations, which can minimize both sonic boom and drag in a supersonic cruising flight. The multi-objective genetic algorithm (MOGA) coupled with the Kriging model has been used to globally and effectively search for optimal design candidates in the multi-objective problem. The drag and the sonic boom have been evaluated by the computational fluid dynamics (CFD) simulation and the waveform parameter method. As a result, the present optimization has successfully obtained low-boom and low-drag design candidates, which are better than the baseline design by more than 40% regarding each performance. Moreover, the structure of design space has been visualized by the self-organizing map (SOM).

  20. A Boom in Boomerangs

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Ted Bailey, a highly-ranked international boomerang designer and thrower, used information from a variety of NASA technical reports on aerodynamics and low-speed airfoils to design more competitive boomerangs. Because the boomerang is essentially an airfoil like an airplane wing, the technology transferred effectively and even contributed to the 1981 American victory over Australian throwers. In 1985, using four NASA reports, Bailey designed a new MTA (maximum time aloft) boomerang that broke the one-minute barrier, enabled throwers to throw and catch in less than three minutes and allowed competitors to complete the difficult "Super Catch" - five throw/catch sequences after launching the original boom while it is still aloft. Bailey is now considering other boomerang applications.

  1. Lightweight Boom For Rescue Helicopter

    NASA Technical Reports Server (NTRS)

    Haslim, Leonard A.

    1993-01-01

    Telescoping boom and associated mechanisms attached to helicopter aid rescue operations by extending lifeline beyond sweep of main rotor. Pilot observes rescuee and control position of helicopter more effectively than if rescuee directly below and hidden from pilot's view. Rescuee outside downdraft of rotor, which is often powerful enough to blow away or submerge someone in water. Used for marine or land operations. Boom thin and lightweight because it need not support weight of rescuee. Lifeline pulls away from boom after secured around rescuee, who is lifted directly into cabin by winch. Potential application for in situ erection of telescopic space structures.

  2. Ultrasonic/Sonic Jackhammer

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph (Inventor); Sherrit, Stewart (Inventor); Herz, Jack L. (Inventor)

    2014-01-01

    The invention provides a novel jackhammer that utilizes ultrasonic and/or sonic vibrations as source of power. It is easy to operate and does not require extensive training, requiring substantially less physical capabilities from the user and thereby increasing the pool of potential operators. An important safety benefit is that it does not fracture resilient or compliant materials such as cable channels and conduits, tubing, plumbing, cabling and other embedded fixtures that may be encountered along the impact path. While the ultrasonic/sonic jackhammer of the invention is able to cut concrete and asphalt, it generates little back-propagated shocks or vibrations onto the mounting fixture, and can be operated from an automatic platform or robotic system. PNEUMATICS; ULTRASONICS; IMPACTORS; DRILLING; HAMMERS BRITTLE MATERIALS; DRILL BITS; PROTOTYPES; VIBRATION

  3. Sonic rhinoplasty: innovative applications.

    PubMed

    Pribitkin, Edmund; Greywoode, Jewel D

    2013-04-01

    Sonic rhinoplasty involves the use of the Sonopet ultrasonic bone aspirator (Stryker, Inc., Kalamazoo, MI, USA) to precisely sculpt the nasal bones without damage to the surrounding nasal cartilage, soft tissue, and mucosa. By employing ultrasonic waves to emulsify and remove bone under concurrent irrigation and suction, sonic rhinoplasty improves upon the conventional osteotome, drill, rasp, and powered rasp techniques that may be associated with decreased visualization, heat generation, mechanical chatter, and a lack of surgical precision with attendant soft tissue injury. We have applied this technology to bony dorsal hump and nasal spine removal, deepening of the glabellar angle and reshaping of irregular nasal contours, septoplasty, turbinate reduction, and the correction of bony asymmetries. PMID:23564245

  4. Boom Softening and Nacelle Integration on an Arrow-Wing High-Speed Civil Transport Concept

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    1999-01-01

    During the last cycle of concept design and wind-tunnel testing, the goal of the low-boom- shaped HSCT concepts (the B-935, the LB-16, and the LB- 1 8) was to meet mission requirements and generate shaped, ground-level pressure signatures with nose shock strengths of 1.0 psf or less. The wind-tunnel tests of these concepts produced results that were partially successful and encouraging although not fully up to expectations. In spite of this, however, these conceptual designs were overly optimistic and not acceptable because: the wing planforms had excessive area; the wing structural aspect ratio was too high; one concept had aft-fuselage rather than under-the-wing engines; and the gross takeoff weights were unrealistically low because of engines that were early, high-tech versions of later, revised, more-realistic engines. The need for reducing the ground-level overpressure shock strengths still existed; a need to be met within more restrictive guidelines of mission performance and gross takeoff weight limitations. Therefore, it was decided that the next conceptual design cycle would focus on decreased nose shock strengths, "boom softening," in the signatures of the Boeing and the McDonnell Douglas baseline concepts rather than low-boom concepts with shaped-signature designs. Overly-optimistic results were not the only problem with these low-sonic-boom concepts. Papers given at the 1994 Sonic-Boom Workshop had demonstrated that the problem of successful nacelle integration on HSCT concepts had only been partially solved. Wind-tunnel pressure signature data, from the HSCT-11B (a.k.a. the LB-18) wind-tunnel model, showed that the Langley HSCT design and analysis method had been successful in reducing the nacelle-volume disturbances in the flow field. This was due.to the engine nacelles mounted behind the wing trailing-edge on the aft fuselage so that no nacelle-wing interference-lift flow-field disturbances were generated. While acceptable from a sonic-boom research

  5. Sonication standard laboratory module

    DOEpatents

    Beugelsdijk, Tony; Hollen, Robert M.; Erkkila, Tracy H.; Bronisz, Lawrence E.; Roybal, Jeffrey E.; Clark, Michael Leon

    1999-01-01

    A standard laboratory module for automatically producing a solution of cominants from a soil sample. A sonication tip agitates a solution containing the soil sample in a beaker while a stepper motor rotates the sample. An aspirator tube, connected to a vacuum, draws the upper layer of solution from the beaker through a filter and into another beaker. This beaker can thereafter be removed for analysis of the solution. The standard laboratory module encloses an embedded controller providing process control, status feedback information and maintenance procedures for the equipment and operations within the standard laboratory module.

  6. Sonic temperature sensor for food processing

    SciTech Connect

    Akers, D.W.; Porter, A.M.; Tow, D.M.

    1997-09-01

    The lack of adequate temperature measurement is the major barrier to the development of more efficient and better quality food processing methods. The objective of the sonic temperature sensor for food processing project is to develop a prototype sensor to noninvasively measure the interior temperature of particulate foods during processing. This, a joint project with the National Food Processors Association, utilizes the property of materials that when the temperature of a material changes, there is a corresponding change in the speed of sound. The approach taken for the sonic sensor system is to determine the speed of sound inside particulate foods using a tomographic reconstruction process. This work has shown that the speed of sound can be accurately determined to an accuracy of {+-}0.4%, corresponding to a temperature uncertainty of {+-}2{degree}C using tomographic reconstruction methods.

  7. Asymmetric neutron emissions from sonicated steel

    NASA Astrophysics Data System (ADS)

    Petrucci, Andrea; Rosada, Alberto; Santoro, Emilio

    2015-05-01

    Following up published works in which we studied and experimentally verified the assumptions of the theory of "Deformed Space-Time" in relation to piezonuclear emissions, and according to previous experiments of sonication by ultrasounds performed on solid materials with high density, cylindrical bars of AISI 304 steel have been sonicated by ultrasounds of the power of 330 Watts and frequency of 20 KHz. We verified by means of passive detectors CR39 (PADC) pulsed emissions of neutrons. In this work, following a recent proposal, it was decided to perform a stereoscopic measurement of neutron emission. It has been verified that they are characterized by a distribution which is anisotropic and asymmetric in the space. The work shows a wide and accurate description of the experiment and the results of neutron emissions, and we stress that there exist two directions corresponding to maximum emission (maximum dose) and zero emission (null dose).

  8. Statistical theories of Langmuir turbulence. II - Subsonic to sonic transition

    NASA Technical Reports Server (NTRS)

    Dubois, D. F.; Rose, H. A.; Nicholson, D. R.

    1985-01-01

    The subsonic limit of the quadratic direct interaction approximation (DIA) applied to the Zakharov equations is compared with the cubic DIA applied to the nonlinear Schroedinger equation, which is the subsonic limit of the Zakharov equations. Comparisons with Monte Carlo simulations of a truncated system show that the first theory more accurately describes the regime of stationary turbulence, while the second theory more accurately describes the subsonic evolution of the modulational instability. The weak turbulence limits of the two theories describe the sonic and subsonic regimes, respectively. The addition of vertex corrections to the DIA leads to a hybrid weak turbulence theory that smoothly interpolates between the sonic and subsonic regimes.

  9. Mixed-Fidelity Approach for Design of Low-Boom Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Li, Wu; Shields, Elwood; Geiselhart, Karl

    2011-01-01

    This paper documents a mixed-fidelity approach for the design of low-boom supersonic aircraft with a focus on fuselage shaping.A low-boom configuration that is based on low-fidelity analysis is used as the baseline. The fuselage shape is modified iteratively to obtain a configuration with an equivalent-area distribution derived from computational fluid dynamics analysis that attempts to match a predetermined low-boom target area distribution and also yields a low-boom ground signature. The ground signature of the final configuration is calculated by using a state-of-the-art computational-fluid-dynamics-based boom analysis method that generates accurate midfield pressure distributions for propagation to the ground with ray tracing. The ground signature that is propagated from a midfield pressure distribution has a shaped ramp front, which is similar to the ground signature that is propagated from the computational fluid dynamics equivalent-area distribution. This result supports the validity of low-boom supersonic configuration design by matching a low-boom equivalent-area target, which is easier to accomplish than matching a low-boom midfield pressure target.

  10. A multilayer sonic film

    NASA Astrophysics Data System (ADS)

    Munteanu, L.; Chiroiu, V.; Sireteanu, T.; Dumitriu, D.

    2015-10-01

    A non-periodic multilayer film was analyzed to show that, despite its non-periodicity, the film exhibits full band-gaps and localized modes at its interfaces, as well as in the sonic composites. The film consists of alternating layers of two different materials that follow a triadic Cantor sequence. The Cantor structure shows extremely low thresholds for subharmonic generation of ultrasonic waves, compared with homogeneous and periodic structures. The coupling between the extended-mode (phonon) and the localized-mode (fracton) vibration regimes explains the generation of full band-gaps, for which there are no propagating Lamb waves. The large enhancement of the nonlinear interaction results from a more favorable frequency and spatial matching of coupled modes. A full band-gap that excludes Love waves is also analyzed.

  11. Evaluation of a new sonic anemometer for routine monitoring and emergency response applications

    SciTech Connect

    Gouveia, F.J; Baskett, R.L.

    1997-02-01

    Recently, several new sonic anemometers have become available for routine wind measurements. Sonic anemometers avoid many problems associated with the traditional rotating anemometer and vane sets- inertia of moving parts, bearing wear, contamination from dust and ice, frequent maintenance. Without a starting threshold, the sonic anemometer also produces more accurate measurements of wind direction and sigma theta at very low wind speeds. We illustrate these advantages by comparing 20 days of observations from a new sonic anemometer with data from existing cup and vane sensors at the 10-m level of Lawrence Livermore National Laboratory`s meteorological tower.

  12. Cost effectiveness of sonic drilling

    SciTech Connect

    Masten, D.; Booth, S.R.

    1996-03-01

    Sonic drilling (combination of mechanical vibrations and rotary power) is an innovative environmental technology being developed in cooperation with DOE`s Arid-Site Volatile Organic Compounds Integrated Demonstration at Hanford and the Mixed Waste Landfill Integrated Demonstration at Sandia. This report studies the cost effectiveness of sonic drilling compared with cable-tool and mud rotary drilling. Benefit of sonic drilling is its ability to drill in all types of formations without introducing a circulating medium, thus producing little secondary waste at hazardous sites. Progress has been made in addressing the early problems of failures and downtime.

  13. The Sonic Altimeter for Aircraft

    NASA Technical Reports Server (NTRS)

    Draper, C S

    1937-01-01

    Discussed here are results already achieved with sonic altimeters in light of the theoretical possibilities of such instruments. From the information gained in this investigation, a procedure is outlined to determine whether or not a further development program is justified by the value of the sonic altimeter as an aircraft instrument. The information available in the literature is reviewed and condensed into a summary of sonic altimeter developments. Various methods of receiving the echo and timing the interval between the signal and the echo are considered. A theoretical discussion is given of sonic altimeter errors due to uncertainties in timing, variations in sound velocity, aircraft speed, location of the sending and receiving units, and inclinations of the flight path with respect to the ground surface. Plots are included which summarize the results in each case. An analysis is given of the effect of an inclined flight path on the frequency of the echo. A brief study of the acoustical phases of the sonic altimeter problem is carried through. The results of this analysis are used to predict approximately the maximum operating altitudes of a reasonably designed sonic altimeter under very good and very bad conditions. A final comparison is made between the estimated and experimental maximum operating altitudes which shows good agreement where quantitative information is available.

  14. Current-driven plasmonic boom instability in three-dimensional gated periodic ballistic nanostructures

    NASA Astrophysics Data System (ADS)

    Aizin, G. R.; Mikalopas, J.; Shur, M.

    2016-05-01

    An alternative approach of using a distributed transmission line analogy for solving transport equations for ballistic nanostructures is applied for solving the three-dimensional problem of electron transport in gated ballistic nanostructures with periodically changing width. The structures with varying width allow for modulation of the electron drift velocity while keeping the plasma velocity constant. We predict that in such structures biased by a constant current, a periodic modulation of the electron drift velocity due to the varying width results in the instability of the plasma waves if the electron drift velocity to plasma wave velocity ratio changes from below to above unity. The physics of such instability is similar to that of the sonic boom, but, in the periodically modulated structures, this analog of the sonic boom is repeated many times leading to a larger increment of the instability. The constant plasma velocity in the sections of different width leads to resonant excitation of the unstable plasma modes with varying bias current. This effect (that we refer to as the superplasmonic boom condition) results in a strong enhancement of the instability. The predicted instability involves the oscillating dipole charge carried by the plasma waves. The plasmons can be efficiently coupled to the terahertz electromagnetic radiation due to the periodic geometry of the gated structure. Our estimates show that the analyzed instability should enable powerful tunable terahertz electronic sources.

  15. Under-Track CFD-Based Shape Optimization for a Low-Boom Demonstrator Concept

    NASA Technical Reports Server (NTRS)

    Wintzer, Mathias; Ordaz, Irian; Fenbert, James W.

    2015-01-01

    The detailed outer mold line shaping of a Mach 1.6, demonstrator-sized low-boom concept is presented. Cruise trim is incorporated a priori as part of the shaping objective, using an equivalent-area-based approach. Design work is performed using a gradient-driven optimization framework that incorporates a three-dimensional, nonlinear flow solver, a parametric geometry modeler, and sensitivities derived using the adjoint method. The shaping effort is focused on reducing the under-track sonic boom level using an inverse design approach, while simultaneously satisfying the trim requirement. Conceptual-level geometric constraints are incorporated in the optimization process, including the internal layout of fuel tanks, landing gear, engine, and crew station. Details of the model parameterization and design process are documented for both flow-through and powered states, and the performance of these optimized vehicles presented in terms of inviscid L/D, trim state, pressures in the near-field and at the ground, and predicted sonic boom loudness.

  16. Boom and chassis articulation joints

    NASA Technical Reports Server (NTRS)

    Murphy, Joel T., Jr.; Nguyen, Vien; Turner, Bonnie; Wheeler, Bobby; Williams, Kimberlyn

    1992-01-01

    The primary goal of our design project was to develop articulation joints for the chassis and boom of the proof-of-concept lunar vehicle. This is an ongoing project and the work of previous student groups was extensively reviewed. Some of the ideas generated are variations of past proposals. Although the project is funded by NASA/USRA, it is totally a student design effort.

  17. Stowage and Deployment of Slit Tube Booms

    NASA Technical Reports Server (NTRS)

    Adams, Larry (Inventor); Turse, Dana (Inventor); Richardson, Doug (Inventor)

    2016-01-01

    A system comprising a boom having a first end, a longitudinal length, and a slit that extends along the longitudinal length of the boom; a drum having an elliptic cross section and a longitudinal length; an attachment mechanism coupled with the first end of the boom and the drum such that the boom and the drum are substantially perpendicular relative to one another; an inner shaft having a longitudinal length, the inner shaft disposed within the drum, the longitudinal length of the inner shaft is aligned substantially parallel with the longitudinal length of the drum, the inner shaft at least partially rotatable relative to the drum, and the inner shaft is at least partially rotatable with the drum; and at least two cords coupled with the inner shaft and portions of the boom near the first end of the boom.

  18. Amplitude loss of sonic waveform due to source coupling to the medium

    USGS Publications Warehouse

    Lee, Myung W.; Waite, William F.

    2007-01-01

    In contrast to hydrate-free sediments, sonic waveforms acquired in gas hydrate-bearing sediments indicate strong amplitude attenuation associated with a sonic velocity increase. The amplitude attenuation increase has been used to quantify pore-space hydrate content by attributing observed attenuation to the hydrate-bearing sediment's intrinsic attenuation. A second attenuation mechanism must be considered, however. Theoretically, energy radiation from sources inside fluid-filled boreholes strongly depends on the elastic parameters of materials surrounding the borehole. It is therefore plausible to interpret amplitude loss in terms of source coupling to the surrounding medium as well as to intrinsic attenuation. Analyses of sonic waveforms from the Mallik 5L-38 well, Northwest Territories, Canada, indicate a significant component of sonic waveform amplitude loss is due to source coupling. Accordingly, all sonic waveform amplitude analyses should include the effect of source coupling to accurately characterize a formation's intrinsic attenuation.

  19. The Sonic Pathfinder: An Evaluation.

    ERIC Educational Resources Information Center

    Dodds, Allan G.; And Others

    1984-01-01

    An objective evaluation of the Sonic Pathfinder, a new ultrasonic mobility aid, showed that use of the aid changes mobility in many ways. Reduced perception of environmental sounds was not reflected in performance. The majority of users traveled slowly and exhibited less than optimal strategies. (Author/CL)

  20. Community Response to an Oil Boom.

    ERIC Educational Resources Information Center

    Copp, James H.

    A study of the process of a 1977-1983 oil and gas boom in Caldwell, Texas, disproved the assumption that local social effects of rapid energy development are severe and negative. Using interviews, surveys, observation, local newspapers, and other writings as data sources, researchers determined that during the boom, Caldwell's population grew…

  1. 33 CFR 401.8 - Landing booms.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Landing booms. 401.8 Section 401.8 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.8 Landing booms. (a)...

  2. The Analysis and Design of Low Boom Configurations Using CFD and Numerical Optimization Techniques

    NASA Technical Reports Server (NTRS)

    Siclari, Michael J.

    1999-01-01

    The use of computational fluid dynamics (CFD) for the analysis of sonic booms generated by aircraft has been shown to increase the accuracy and reliability of predictions. CFD takes into account important three-dimensional and nonlinear effects that are generally neglected by modified linear theory (MLT) methods. Up to the present time, CFD methods have been primarily used for analysis or prediction. Some investigators have used CFD to impact the design of low boom configurations using trial and error methods. One investigator developed a hybrid design method using a combination of Modified Linear Theory (e.g. F-functions) and CFD to provide equivalent area due to lift driven by a numerical optimizer to redesign or modify an existing configuration to achieve a shaped sonic boom signature. A three-dimensional design methodology has not yet been developed that completely uses nonlinear methods or CFD. Constrained numerical optimization techniques have existed for some time. Many of these methods use gradients to search for the minimum of a specified objective function subject to a variety of design variable bounds, linear and nonlinear constraints. Gradient based design optimization methods require the determination of the objective function gradients with respect to each of the design variables. These optimization methods are efficient and work well if the gradients can be obtained analytically. If analytical gradients are not available, the objective gradients or derivatives with respect to the design variables must be obtained numerically. To obtain numerical gradients, say, for 10 design variables, might require anywhere from 10 to 20 objective function evaluations. Typically, 5-10 global iterations of the optimizer are required to minimize the objective function. In terms of using CFD as a design optimization tool, the numerical evaluation of gradients can require anywhere from 100 to 200 CFD computations per design for only 10 design variables. If one CFD

  3. High Precision UTDR Measurements by Sonic Velocity Compensation with Reference Transducer

    PubMed Central

    Stade, Sam; Kallioinen, Mari; Mänttäri, Mika; Tuuva, Tuure

    2014-01-01

    An ultrasonic sensor design with sonic velocity compensation is developed to improve the accuracy of distance measurement in membrane modules. High accuracy real-time distance measurements are needed in membrane fouling and compaction studies. The benefits of the sonic velocity compensation with a reference transducer are compared to the sonic velocity calculated with the measured temperature and pressure using the model by Belogol'skii, Sekoyan et al. In the experiments the temperature was changed from 25 to 60 °C at pressures of 0.1, 0.3 and 0.5 MPa. The set measurement distance was 17.8 mm. Distance measurements with sonic velocity compensation were over ten times more accurate than the ones calculated based on the model. Using the reference transducer measured sonic velocity, the standard deviations for the distance measurements varied from 0.6 to 2.0 μm, while using the calculated sonic velocity the standard deviations were 21–39 μm. In industrial liquors, not only the temperature and the pressure, which were studied in this paper, but also the properties of the filtered solution, such as solute concentration, density, viscosity, etc., may vary greatly, leading to inaccuracy in the use of the Belogol'skii, Sekoyan et al. model. Therefore, calibration of the sonic velocity with reference transducers is needed for accurate distance measurements. PMID:24991939

  4. High precision UTDR measurements by sonic velocity compensation with reference transducer.

    PubMed

    Stade, Sam; Kallioinen, Mari; Mänttäri, Mika; Tuuva, Tuure

    2014-01-01

    An ultrasonic sensor design with sonic velocity compensation is developed to improve the accuracy of distance measurement in membrane modules. High accuracy real-time distance measurements are needed in membrane fouling and compaction studies. The benefits of the sonic velocity compensation with a reference transducer are compared to the sonic velocity calculated with the measured temperature and pressure using the model by Belogol'skii, Sekoyan et al. In the experiments the temperature was changed from 25 to 60 °C at pressures of 0.1, 0.3 and 0.5 MPa. The set measurement distance was 17.8 mm. Distance measurements with sonic velocity compensation were over ten times more accurate than the ones calculated based on the model. Using the reference transducer measured sonic velocity, the standard deviations for the distance measurements varied from 0.6 to 2.0 µm, while using the calculated sonic velocity the standard deviations were 21-39 µm. In industrial liquors, not only the temperature and the pressure, which were studied in this paper, but also the properties of the filtered solution, such as solute concentration, density, viscosity, etc., may vary greatly, leading to inaccuracy in the use of the Belogol'skii, Sekoyan et al. model. Therefore, calibration of the sonic velocity with reference transducers is needed for accurate distance measurements. PMID:24991939

  5. A Performance Assessment of Eight Low-Boom High-Speed Civil Transport Concepts

    NASA Technical Reports Server (NTRS)

    Baize, Daniel G.; McElroy, Marcus O.; Fenbert, James A.; Coen, Peter G.; Ozoroski, Lori P.; Domack, Chris S.; Needleman, Kathy E.; Geiselhart, Karl A.

    1999-01-01

    A performance assessment of eight low-boom high speed civil transport (HSCT) configurations and a reference HSCT configuration has been performed. Although each of the configurations was designed with different engine concepts, for consistency, a year 2005 technology, 0.4 bypass ratio mixed-flow turbofan (MFTF) engine was used for all of the performance assessments. Therefore, all original configuration nacelles were replaced by a year 2005 MFRF nacelle design which corresponds to the engine deck utilized. The engine thrust level was optimized to minimize vehicle takeoff gross weight. To preserve the configuration's sonic-boom shaping, wing area was not optimized or altered from its original design value. Performance sizings were completed when possible for takeoff balanced field lengths of 11,000 ft and 12,000 ft, not considering FAR Part 36 Stage III noise compliance. Additionally, an arbitrary sizing with thrust-to-weight ratio equal to 0.25 was performed, enabling performance levels to be compared independent of takeoff characteristics. The low-boom configurations analyzed included designs from the Boeing Commercial Airplane Group, Douglas Aircraft Company, Ames Research Center, and Langley Research Center. This paper discusses the technology level assumptions, mission profile, analysis methodologies, and the results of the assessment. The results include maximum lift-to-drag ratios, total fuel consumption, number of passengers, optimum engine sizing plots, takeoff performance, mission block time, and takeoff gross weight for all configurations. Results from the low-boom configurations are also compared with a non-low-boom reference configuration. Configuration dependent advantages or deficiencies are discussed as warranted.

  6. High Speed Research Program Sonic Fatigue

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A. (Technical Monitor); Beier, Theodor H.; Heaton, Paul

    2005-01-01

    The objective of this sonic fatigue summary is to provide major findings and technical results of studies, initiated in 1994, to assess sonic fatigue behavior of structure that is being considered for the High Speed Civil Transport (HSCT). High Speed Research (HSR) program objectives in the area of sonic fatigue were to predict inlet, exhaust and boundary layer acoustic loads; measure high cycle fatigue data for materials developed during the HSR program; develop advanced sonic fatigue calculation methods to reduce required conservatism in airframe designs; develop damping techniques for sonic fatigue reduction where weight effective; develop wing and fuselage sonic fatigue design requirements; and perform sonic fatigue analyses on HSCT structural concepts to provide guidance to design teams. All goals were partially achieved, but none were completed due to the premature conclusion of the HSR program. A summary of major program findings and recommendations for continued effort are included in the report.

  7. Counterexamples to the Sonic Criterion

    NASA Astrophysics Data System (ADS)

    Elling, Volker

    2009-12-01

    We consider self-similar (pseudo-steady) shock reflection at an oblique wall. There are three parameters: wall corner angle, Mach number, angle of incident shock. Ever since Ernst Mach discovered the irregular reflection named after him, researchers have sought to predict precisely for which parameters the reflection is regular. Three conflicting proposals—the detachment, sonic and von Neumann criteria—have been studied extensively without a clear result. We demonstrate that the sonic criterion is not correct. We consider polytropic potential flow and prove that there is an open nonempty set of parameters that admit a global regular reflection with a reflected shock that is transonic. We also provide a clear physical reason: the flow type (sub- or supersonic) is not decisive; instead the reflected shock type (weak or strong) determines whether structural perturbations decay towards the reflection point.

  8. Review of sonic fatigue technology

    NASA Technical Reports Server (NTRS)

    Clarkson, B. L.

    1994-01-01

    From the early-1960s until the mid-1980s, there was very little theoretical development for sonic fatigue prediction. Design nomographs based on simple theoretical models and results of specially designed tests were developed for most common aircraft structures. The use of advanced composites in the 1980s, however, generated an increased interest in development of more sophisticated theoretical models because of the possibilities for a much wider range of structural designs. The purpose of this report is to review sonic fatigue technology and, in particular, to assess recent developments. It also suggests a plan for a coordinated program of theoretical and experimental work to meet the anticipated needs of future aerospace vehicles.

  9. Dispersion of Single Walled Carbon Nanotubes Using a Novel Type of Sonication: Focused Sonication.

    PubMed

    Sachin, Bramhe N; Ae, Hwangbo Seon; Chu, Min Cheol

    2016-03-01

    We demonstrate the use of novel type of sonication method, focused sonication, with added advantages over bath and probe type of sonication for the dispersion of single walled carbon nanotubes (SWNT). Di-chloro benzene was used as the solvent for dispersion of SWNT. Results from focused sonication and bath sonication were compared and found that focused sonication results in better dispersion. Also Raman spectroscopy was analysed to ascertain if focused sonication causes any damage to the tubes and it was found that there was no damage to the SWNT. We believe that with the added advantages like in-situ temperature control and large sample volume processing, focused sonication would prove to be the most proficient method of sonication for dispersion of nanoparticles. PMID:27455717

  10. Optimisation of sonic thermographic inspection

    NASA Astrophysics Data System (ADS)

    Tsoi, Kelly A.; Yousif, Khalid; Rajic, Nik; Powlesland, Ian

    2009-03-01

    A versatile and broad-field technique, sonic thermography uses high intensity acoustic waves to induce frictional heating at defect locations and the thermal signature is then detected using IR imaging. Sonic thermography has the potential to be used as a quantitative technique for difficult inspection problems. One example is the inspection of interference fit fasteners. In the case of poorly fitted interference fasteners, the acoustic waves induce relative motion between the fastener and host, causing frictional heating which can then be detected. The preliminary results of an inspection of interference fit levels in fastened metallic plates, reminiscent of the F-111C wing skin, are discussed. By improving the repeatability of the acoustic energy transfer, the heat detected using the IR thermographic system can be correlated to the interference fit levels of the fasteners. The results provide encouragement for the development of a quantitative assessment capability, however one of the remaining critical issues, which has hindered the use of sonic thermography as a quantitative technique, is the poor repeatability of acoustic excitations. This paper will also report on an experimental study which investigates this repeatability issue, in particular the role of the interface material used between the horn tip and the structure to enhance energy transfer.

  11. Sonic Booms and Diffusion Wakes Generated by a Heavy Quark in Thermal Gauge-String Duality

    SciTech Connect

    Gubser, Steven S.; Pufu, Silviu S.; Yarom, Amos

    2008-01-11

    We evaluate the Poynting vector generated by a heavy quark moving through a thermal state of N=4 gauge theory using the gauge-string duality. A significant diffusion wake is observed as well as a Mach cone. We discuss the ratio of the energy going into sound modes to the energy coming in from the wake.

  12. The effect of a coastline on the underwater penetration of sonic booms.

    PubMed

    Garrelick, Joel

    2002-01-01

    A simplified analysis is presented for the underwater noise levels from a steady supersonic flight traversing a coastline. The effect of the coast is to introduce a propagating noise component that does not exhibit the classic evanescent attenuation with depth for flights subsonic in water. Expressions are given to estimate the boundary of, and levels within, the coastal region where this component dominates. An illustrative example is presented. PMID:11837966

  13. Sonic booms and diffusion wakes generated by a heavy quark in thermal gauge-string duality.

    PubMed

    Gubser, Steven S; Pufu, Silviu S; Yarom, Amos

    2008-01-11

    We evaluate the Poynting vector generated by a heavy quark moving through a thermal state of N=4 gauge theory using the gauge-string duality. A significant diffusion wake is observed as well as a Mach cone. We discuss the ratio of the energy going into sound modes to the energy coming in from the wake. PMID:18232753

  14. Effect of stratification and geometrical spreading on sonic boom rise time

    NASA Technical Reports Server (NTRS)

    Cleveland, Robin O.; Hamilton, Mark F.; Blackstock, David T.

    1994-01-01

    The purpose of our investigation is to determine the effect of unsteadiness (not associated with turbulence) on rise time. The unsteadiness considered here is due to (1) geometrical spreading, (2) stratification, which includes variation in density, temperature, and relative humidity, and (3) N shaped waveform. A very general Burgers equation, which includes all these effects, is the propagation model for our study. The equation is solved by a new computational algorithm in which all the calculations are done in the time domain. The present paper is a progress report in which some of the factors contributing to unsteadiness are studied, namely geometrical spreading and variation in relative humidity. The work of Pierce and Kang, which motivated our study, is first reviewed. We proceed with a discussion of the Burgers equation model and the algorithm for solving the equation. Some comparison tests to establish the validity of the algorithm are presented. The algorithm is then used to determine the distance required for a steady-state shock, on encountering an abrupt change in relative humidity, to reach a new steady state based on the new humidity. It is found that the transition distance for plane shocks of amplitude 70 Pa is about 4 km when the change in relative humidity is 10 percent. Shocks of amplitude 140 Pa require less distance. The effect of spherical and cylindrical spreading is also considered. We demonstrate that a spreading shock wave never reaches steady state and that its rise time will be less than the equivalent steady state shock. Finally we show that an N wave has a slightly shorter rise time than a step shock of the same amplitude.

  15. PERFORMANCE TESTING OF SELECTED SORBENT BOOMS

    EPA Science Inventory

    Performance tests on three commercially available sorbent booms were conducted at the U.S. Environmental Protection Agency's Oil and Hazardous Materials Simulated Environmental Test Tank (OHMSETT) test facility. Test variables included wave condition, tow speed, and quantity of o...

  16. Was There Really a Popular Science "Boom"?

    ERIC Educational Resources Information Center

    Lewenstein, Bruce V.

    1987-01-01

    Traces the major developments and trends in contemporary popular science. Identifies magazines, television shows, and newspaper sections devoted to popular science and discusses their status and impact. Comments on the rise, fall, and future of the "science boom." (ML)

  17. Adaptive Aft Signature Shaping of a Low-Boom Supersonic Aircraft Using Off-Body Pressures

    NASA Technical Reports Server (NTRS)

    Ordaz, Irian; Li, Wu

    2012-01-01

    The design and optimization of a low-boom supersonic aircraft using the state-of-the- art o -body aerodynamics and sonic boom analysis has long been a challenging problem. The focus of this paper is to demonstrate an e ective geometry parameterization scheme and a numerical optimization approach for the aft shaping of a low-boom supersonic aircraft using o -body pressure calculations. A gradient-based numerical optimization algorithm that models the objective and constraints as response surface equations is used to drive the aft ground signature toward a ramp shape. The design objective is the minimization of the variation between the ground signature and the target signature subject to several geometric and signature constraints. The target signature is computed by using a least-squares regression of the aft portion of the ground signature. The parameterization and the deformation of the geometry is performed with a NASA in- house shaping tool. The optimization algorithm uses the shaping tool to drive the geometric deformation of a horizontal tail with a parameterization scheme that consists of seven camber design variables and an additional design variable that describes the spanwise location of the midspan section. The demonstration cases show that numerical optimization using the state-of-the-art o -body aerodynamic calculations is not only feasible and repeatable but also allows the exploration of complex design spaces for which a knowledge-based design method becomes less effective.

  18. Is amplitude loss of sonic waveforms due to intrinsic attenuation or source coupling to the medium?

    USGS Publications Warehouse

    Lee, Myung W.

    2006-01-01

    Sonic waveforms acquired in gas-hydrate-bearing sediments indicate strong amplitude loss associated with an increase in sonic velocity. Because the gas hydrate increases sonic velocities, the amplitude loss has been interpreted as due to intrinsic attenuation caused by the gas hydrate in the pore space, which apparently contradicts conventional wave propagation theory. For a sonic source in a fluid-filled borehole, the signal amplitude transmitted into the formation depends on the physical properties of the formation, including any pore contents, in the immediate vicinity of the source. A signal in acoustically fast material, such as gas-hydrate-bearing sediments, has a smaller amplitude than a signal in acoustically slower material. Therefore, it is reasonable to interpret the amplitude loss in the gas-hydrate-bearing sediments in terms of source coupling to the surrounding medium as well as intrinsic attenuation. An analysis of sonic waveforms measured at the Mallik 5L-38 well, Northwest Territories, Canada, indicates that a significant part of the sonic waveform's amplitude loss is due to a source-coupling effect. All amplitude analyses of sonic waveforms should include the effect of source coupling in order to accurately characterize the formation's intrinsic attenuation.

  19. Activities of the Boom and Chassis Group

    NASA Technical Reports Server (NTRS)

    Dell, Jason Scott; Meeks, Thomas Bayne; Merkel, Kelly; Nelson, Brent; Winchell, Tom

    1992-01-01

    Group One of the NASA Lunar Enabler Project has designed the primary chassis and boom structures for the lunar vehicle. Both components also feature V-clamps that were adapted to interface connections within the structure. The chassis features a front end, rear end section, middle cross-section, and face plate. The rear section contains an extra compartment for the engine, hydraulic pump, fuel bottles, and oil reservoir necessary for the wheel drives. Each section consists of tubular aluminum 6061-T6. The boom features four degrees of freedom system, where the minimum factor of safety of any part is 1.5 (but, normally much higher). It consists of a tapered upper boom, lower boom, and three elbows that complement the articulation joints. Each section of the boom has been constructed from aluminum 6061-T6. There are four joints and eight V-clamps in the boom assembly. The V-clamps feature support rings that prevent axial rotation. They provide easy adaptability and assembly.

  20. Permeability extraction: A sonic log inversion

    SciTech Connect

    Akbar, N.; Kim, J.J.

    1994-12-31

    In this paper the authors provide the missing important link between permeability and acoustic velocities by generating a permeability-dependent synthetic sonic log in a carbonate reservoir. The computations are based on Akbar`s theory that relates wave velocity to frequency, rock properties (e.g., lithology, permeability, and porosity), and fluid saturation and properties (viscosity, density, and compressibility). An inverted analytical expression of the theory is used to extract permeability from sonic velocity. The synthetic sonic and the computed permeability are compared with the observed sonic log and with plug permeability, respectively. The results demonstrate, as predicted by theory, that permeability can be related directly to acoustic velocities.

  1. Ultrasonic/Sonic Impacting Penetrators

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Chang, Zensheu; Sherrit, Stewart; Stark, Randall A.

    2008-01-01

    Ultrasonic/sonic impacting penetrators (USIPs) are recent additions to the series of apparatuses based on ultrasonic/sonic drill corers (USDCs). A USIP enables a rod probe to penetrate packed soil or another substance of similar consistency, without need to apply a large axial force that could result in buckling of the probe or in damage to some buried objects. USIPs were conceived for use in probing and analyzing soil to depths of tens of centimeters in the vicinity of buried barrels containing toxic waste, without causing rupture of the barrels. USIPs could also be used for other purposes, including, for example, searching for pipes, barrels, or other hard objects buried in soil; and detecting land mines. USDCs and other apparatuses based on USDCs have been described in numerous previous NASA Tech Briefs articles. The ones reported previously were designed, variously, for boring into, and/or acquiring samples of, rock or other hard, brittle materials of geological interest. To recapitulate: A USDC can be characterized as a lightweight, low-power, piezoelectrically driven jackhammer in which ultrasonic and sonic vibrations are generated and coupled to a tool bit. As shown in the figure, a basic USDC includes a piezoelectric stack, a backing and a horn connected to the stack, a free mass (free in the sense that it can slide axially a short distance between the horn and the shoulder of tool bit), and a tool bit, i.e., probe for USIP. The piezoelectric stack is driven at the resonance frequency of the stack/horn/backing assembly to create ultrasonic vibrations that are mechanically amplified by the horn. To prevent fracture during operation, the piezoelectric stack is held in compression by a bolt. The bouncing of the free mass between the horn and the tool bit at sonic frequencies generates hammering actions to the bit that are more effective for drilling than is the microhammering action of ultrasonic vibrations in ordinary ultrasonic drills. The hammering actions

  2. Boom Rendezvous Alternative Docking Approach

    NASA Technical Reports Server (NTRS)

    Bonometti, Joseph A.

    2006-01-01

    Space rendezvous and docking has always been attempted with primarily one philosophic methodology. The slow matching of one vehicle's orbit by a second vehicle and then a final closing sequence that ends in matching the orbits with perfect precision and with near zero relative velocities. The task is time consuming, propellant intensive, risk inherent (plume impingement, collisions, fuel depletion, etc.) and requires substantial hardware mass. The historical background and rationale as to why this approach is used is discussed in terms of the path-not-taken and in light of an alternate methodology. Rendezvous and docking by boom extension is suggested to have inherent advantages that today s technology can readily exploit. Extension from the primary spacecraft, beyond its inherent large inertia, allows low inertia connections to be made rapidly and safely. Plume contamination issues are eliminated as well as the extra propellant mass and risk required for the final thruster (docking) operations. Space vehicle connection hardware can be significantly lightened. Also, docking sensors and controls require less fidelity; allowing them to be more robust and less sensitive. It is the potential safety advantage and mission risk reduction that makes this approach attractive, besides the prospect of nominal time and mass savings.

  3. Sleipner mishap jolts booming Norway

    SciTech Connect

    Not Available

    1991-09-02

    This paper reports on Norway's buoyant offshore industry that was stunned when the concrete substructure for Sleipner natural gas field's main production platform sank in the Grandsfjord off Stavanger late last month. The accident, a blow to Norway's gas sales program in Europe, came with offshore activity in the Norwegian North Sea moving into a new boom period. Currently, 10 oil and gas fields are under development, and several projects are on the drawing board. Aker Oil and Gas, a leading offshore firm, says the country's construction industry will be working at capacity for the next 4 years. Norwegian oil production has been hovering just below 2 million b/d since the beginning of this year, making Norway the North Sea's largest producer, a position formerly held by the U.K. Gas production averages about 3 bcfd. With European gas demand sharply increasing, Norway is under pressure to increase output from new fields in the mid to late 1990s. The Sleipner setback forces state owned Den norske stats oljeselskap AS (Statoil) to cast around for supplies. Sleipner was to have begun deliveries to a consortium of continental gas companies in October 1993. Statoil believes it can fill the gap from existing fields in Norwegian waters.

  4. Sonic temperature sensor for food processing. Final report

    SciTech Connect

    1998-06-01

    The lack of adequate temperature measurement is the major barrier to the development of more efficient and better quality food processing methods. The objective of the sonic temperature sensor for food processing project is to develop a prototype sensor system to noninvasively measure the interior temperature of particulate foods during processing. The development of the prototype sensor is a collaborative project with the National Food Processors Association. The project is based on the property of materials that involves a change in the temperature of a material having a corresponding change in the speed of sound. The approach for the sonic sensor system is to determine the speed of sound through particulate foods using a tomographic reconstruction process. This work has shown that the speed of sound accurately can be determined using tomographic reconstruction methods to an accuracy of {+-} 0.4%, which corresponds to a temperature uncertainty of {+-}2{degrees}C.

  5. Conceptual Design of Low-Boom Aircraft with Flight Trim Requirement

    NASA Technical Reports Server (NTRS)

    Ordaz, Irian; Geiselhart, Karl A.; Fenbert, James W.

    2014-01-01

    A new low-boom target generation approach is presented which allows the introduction of a trim requirement during the early conceptual design of supersonic aircraft. The formulation provides an approximation of the center of pressure for a presumed aircraft configuration with a reversed equivalent area matching a low-boom equivalent area target. The center of pressure is approximated from a surrogate lift distribution that is based on the lift component of the classical equivalent area. The assumptions of the formulation are verified to be sufficiently accurate for a supersonic aircraft of high fineness ratio through three case studies. The first two quantify and verify the accuracy and the sensitivity of the surrogate center of pressure corresponding to shape deformation of lifting components. The third verification case shows the capability of the approach to achieve a trim state while maintaining the low-boom characteristics of a previously untrimmed configuration. Finally, the new low-boom target generation approach is demonstrated through the early conceptual design of a demonstrator concept that is low-boom feasible, trimmed, and stable in cruise.

  6. An Evaluation of Measured Pressure Signatures From Wind-Tunnel Models of Three Low-Boom Concepts

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.

    2005-01-01

    Revised 1990-1991 sonic-boom design and analysis methodology was assessed by applying it to the design of three low-boom concepts. Models of these concepts were built and used to measure pressure signatures in the wind tunnel. An analysis of wind-tunnel data showed unexpected nacelle-inlet and the nacelle-wing interference-lift shocks in the pressure signatures from the two engine-under-the-wing models, but not in the measured pressure signatures from the wind-tunnel model with the engine nacelles mounted on the aft fuselage. However, additional lift-induced shocks were found in the pressure signature data from all three wind-tunnel models indicating that other flow-field disturbance effects were present.

  7. Using homogenization, sonication and thermo-sonication to inactivate fungi.

    PubMed

    Campaniello, Daniela; Bevilacqua, Antonio; Sinigaglia, Milena; Corbo, Maria Rosaria

    2016-01-01

    Ultrasound (US), Thermo-sonication (TS) and High Pressure Homogenization (HPH) were studied as tools to inactivate the spores of Penicillium spp. and Mucor spp. inoculated in distilled water. For US, the power ranged from 40% to 100%, pulse from 2 to 10 s, and duration of the treatment from 2 to 10 min. TS was performed combining US (40-80% of power, for 8 min and pulse of 2 s) with a thermal treatment (50, 55 and 60°C at 4, 8 and 12 min). Homogenization was done at 30-150 MPa for 1, 2 and 3 times. Power was the most important factors to determine the antifungal effect of US and TS towards the conidia of Penicillium spp.; on the other hand, in US treatments Mucor spp. was also affected by pulse and time. HPH exerted a significant antifungal effect only if the highest pressures were applied for 2-3 times. PMID:27375964

  8. Using homogenization, sonication and thermo-sonication to inactivate fungi

    PubMed Central

    Bevilacqua, Antonio; Sinigaglia, Milena; Corbo, Maria Rosaria

    2016-01-01

    Ultrasound (US), Thermo-sonication (TS) and High Pressure Homogenization (HPH) were studied as tools to inactivate the spores of Penicillium spp. and Mucor spp. inoculated in distilled water. For US, the power ranged from 40% to 100%, pulse from 2 to 10 s, and duration of the treatment from 2 to 10 min. TS was performed combining US (40–80% of power, for 8 min and pulse of 2 s) with a thermal treatment (50, 55 and 60°C at 4, 8 and 12 min). Homogenization was done at 30–150 MPa for 1, 2 and 3 times. Power was the most important factors to determine the antifungal effect of US and TS towards the conidia of Penicillium spp.; on the other hand, in US treatments Mucor spp. was also affected by pulse and time. HPH exerted a significant antifungal effect only if the highest pressures were applied for 2–3 times. PMID:27375964

  9. Graphite Composite Booms with Integral Hinges

    NASA Technical Reports Server (NTRS)

    Alexander, Wes; Carlos, Rene; Rossoni, Peter; Sturm, James

    2006-01-01

    A document discusses lightweight instrument booms under development for use aboard spacecraft. A boom of this type comprises a thin-walled graphite fiber/ matrix composite tube with an integral hinge that can be bent for stowage and later allowed to spring back to straighten the boom for deployment in outer space. The boom design takes advantage of both the stiffness of the composite in tubular geometry and the flexibility of thin sections of the composite. The hinge is formed by machining windows in the tube at diametrically opposite locations so that there remain two opposing cylindrical strips resembling measuring tapes. Essential to the design is a proprietary composite layup that renders the hinge tough yet flexible enough to be bendable as much as 90 in either of two opposite directions. When the boom is released for deployment, the torque exerted by the bent hinge suffices to overcome parasitic resistance from harnesses and other equipment, so that the two sections of the hinge snap to a straight, rigid condition in the same manner as that of measuring tapes. Issues addressed in development thus far include selection of materials, out-of-plane bending, edge cracking, and separation of plies.

  10. Stakeholder acceptance analysis ResonantSonic drilling

    SciTech Connect

    Peterson, T.

    1995-12-01

    This report presents evaluations, recommendations, and requirements concerning ResonantSonic Drilling (Sonic Drilling), derived from a three-year program of stakeholder involvement. Sonic Drilling is an innovative method to reach contamination in soil and groundwater. The resonant sonic drill rig uses counter-rotating weights to generate energy, which causes the drill pipe to vibrate elastically along its entire length. In the resonant condition, forces of up to 200,000 pounds are transmitted to the drill bit face to create a cutting action. The resonant energy causes subsurface materials to move back into the adjacent formation, permitting the drill pipe to advance. This report is for technology developers and those responsible for making decisions about the use of technology to remediate contamination by volatile organic compounds. Stakeholders` perspectives help those responsible for technology deployment to make good decisions concerning the acceptability and applicability of sonic drilling to the remediation problems they face.

  11. Development of the sonic pump levitation

    NASA Technical Reports Server (NTRS)

    Dunn, S. A.

    1984-01-01

    A prototype levitating/positioning device termed the Sonic Pump Levitator was designed, built and successfully tested in full gravity and in the reduced gravity of the parabolic flight regime of the KC-135. Positioning is achieved by timely and appropriate application of gas momentum from one or more of six sonic pumps. The sonic pumps, which are arranged orthogonally in opposed pairs about the levitation region, are activated by an electro-optical, computer controlled, feedback system. The sonic pump is a transducer which is capable of converting sound energy into a directed flow of gas. It consists of a loudspeaker whose face is sealed by a closure perforated by one or more orifices. The diaphragm of the loudspeaker is the only moving part of the sonic pump, no valves being needed. This very low inertia electromechanical device was developed to provide the short response time necessary to keep pace with the demands of computerized position keeping.

  12. Thermal static bending of deployable interlocked booms

    NASA Technical Reports Server (NTRS)

    Staugaitis, C. L.; Predmore, R. E.

    1973-01-01

    Metal ribbons processed with a heat-forming treatment are enabled to form tubelike structures when deployed from a roll. Deployable booms of this have been utilized for gravity-gradient stabilization on the RAE, ATS, and Nimbus D satellites. An experimental thermal-mechanics test apparatus was developed to measure the thermal static bending and twist of booms up to 3 meters long. The apparatus was calibrated by using the correlation between calculated and observed thermal bending of a seamless tube. Thermal static bending values of 16 interlocked deployable booms were observed to be within a factor of 2.5 of the values calculated from seamless-tube theory. Out-of-Sun-plane thermal bending was caused by complex heat transfer across the interlocked seam. Significant thermal static twisting was not observed.

  13. DEPLOYMENT CONFIGURATIONS FOR IMPROVED OIL CONTAINMENT WITH SELECTED SORBENT BOOMS

    EPA Science Inventory

    Performance tests on three catenary oil containment configurations using sorbent booms sections alone and in conjunction with a conventional containment boom, were conducted at the U.S. Environmental Protection Agency's Oil and Hazardous Materials Simulated Environmental Test Tan...

  14. 53. VIEW OF PASSENGER SPEEDER 04 IN FOREGROUND, BOOM SPEEDER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. VIEW OF PASSENGER SPEEDER 04 IN FOREGROUND, BOOM SPEEDER 75 IN BACKGROUND LEFT, AND BOOM SPEEDER 59 IN BACKGROUND RIGHT - Electron Hydroelectric Project, Along Puyallup River, Electron, Pierce County, WA

  15. A Mystery Unraveled: Booming Sand Dunes

    NASA Astrophysics Data System (ADS)

    Vriend, N. M.; Hunt, M. L.; Clayton, R. W.

    2007-12-01

    "Booming" sand dunes have intrigued travelers and scientist for centuries. These dunes emit a persistent, low-frequency sound during a slumping event or a natural avalanche on the leeward face of the dune. The sound can last for several minutes and be audible from miles away. The resulting acoustic emission is characterized by a dominant audible frequency (70 - 105 Hz) and several higher harmonics. In the work of Vriend et al. (2007), seismic refraction experiments proved the existence of a multi-layer internal structure in the dune that acts as a waveguide for the acoustic energy. Constructive interference between the reflecting waves enables the amplification and sets the frequency of each boom. A relationship was established that correctly predicts the measured frequency in terms of the thickness (~ 2.0 m) and the seismic body wave velocity of the loose, dry surficial layer (~ 240 m/s) and the substrate half-space (~ 350 m/s). The current work highlights additional measurements and simulations supporting the waveguide model for booming sand dunes. Experiments with ground penetrating radar continuously display the subsurface features which confirm the layered subsurface structure within the dune. Cross-correlation analysis shows that the booming sound propagates at speeds close to the measured body wave velocity. Squeaking sounds, which are generated during the onset of the slide and precede the sustained booming emission, have been found to have distinctly different characteristics. These short bursts of sound are emitted at a lower frequency (50 - 65 Hz) and propagate at a lower propagation speed (125 m/s) than the booming emission. The acoustic and elastic wave propagation in the dune has been simulated with a finite difference code. The interaction between the air and the ground produces a coupling wave along the surface. The reflections in the surficial layer propagate in a dispersive band at a group velocity that is slower than the phase velocity of the

  16. Sonic fatigue of launch vehicle components

    SciTech Connect

    Wentz, K.R.; Camden, M.P.

    1997-01-01

    Wright Laboratory has long been a leader in the technologies required for aerospace structures. One of these driving technology areas is that of the dynamic environments of acoustics and vibration to which structures are exposed and required to survive. This paper presents an overview of sonic fatigue of launch vehicle components. An experimental program to develop sonic fatigue design criteria for a proposed thermal protection system is reviewed. Wright Laboratory{close_quote}s experimental facilities utilized to subject structures to simulated launch vehicle environments which are necessary to generate the experimental data required to provide sonic fatigue design criteria are described. {copyright} {ital 1997 American Institute of Physics.}

  17. Micro-sonicator for spore lysis

    DOEpatents

    Miles, Robin R.; Belgrader, Phillip; Nasarabadi, Shanavaz L.

    2000-01-01

    A micro-sonicator for spore lysis. Using micromachining technology, the micro-sonicator uses ultrasonic excitation of spores to perform spore and cell lysis. The micro-sonicator comprises a container with a cavity therein for retaining the sample in an ultrasonic transmission medium, the cavity being closed by a silicon membrane to which an electrode and piezoelectric material are attached, with the electrode and piezoelectric material being electrically connected to an AC signal generator which causes the membrane to flex and vibrate at the frequency of the applied voltage.

  18. F-16XL ship #1 and SR-71 in formation flight with afterburner studying the characteristics of sonic

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The single-seat F-16XL NASA 849, with it's afterburner firing, on a flight for the recent sonic boom research program conducted by the Dryden Flight Research Center, Edwards, California., conducted with an SR-71A, NASA 844. During the missions, the F-16XL probed the shockwaves generated by the SR-71, while at lower altitudes sensors on an F-18 and on a YO-3A, and also on the ground, recorded data from the same shockwave. Information from the program, managed by NASA's Langely Research Center, is being used for NASA's High Speed Research program.

  19. Babies Bottom Out--A 'Maybe Boom'

    ERIC Educational Resources Information Center

    Science News, 1977

    1977-01-01

    Data for the period September 1976 through April 1977 indicate a rise in the United States birth rate; however, the rate is still below the replacement level. It is speculated that the increase is an "echo" effect to the post-World War II baby boom which peaked in 1957. (SL)

  20. Structural evaluation of deployable aerodynamic spike booms

    NASA Technical Reports Server (NTRS)

    Richter, B. J.

    1975-01-01

    An extendable boom consisting of a series of telescopic cylindrical tube segments and overlapping lock joints developed for use as an aerodynamic spike mounted atop a missile is described. Two candidate design concepts differing mainly in the particular overlapping lock joint designs are undergoing a combined analytical/experimental evaluation. Some of the results of this evaluation are presented.

  1. The Baby Boom--Entering Midlife.

    ERIC Educational Resources Information Center

    Bouvier, Leon F.; De Vita, Carol J.

    1991-01-01

    The U.S. baby-boom generation, born between 1946 and 1964, is the largest generation in the nations's history. Numbering over 80 million people in 1990, this giant generation has indelibly changed U.S. society, requiring adjustments in schools, labor markets, housing markets, and government programs. Perhaps more than any other institution,…

  2. Mapping the Stratigraphy of Booming Sand Dunes

    NASA Astrophysics Data System (ADS)

    Vriend, N. M.; Hunt, M. L.; Clayton, R. W.

    2008-12-01

    Booming dunes emit a loud rumbling sound after a man-made or natural sand avalanche is generated on the slip face of a large desert dune. The sound consist of one dominant frequency (70 - 105 Hz) with several higher harmonics. A recent publication (Vriend et al., 2007) presented a model of an internal, natural waveguide that propagates the booming emission, amplifies the sound, and sets the booming frequency. The mapping of the subsurface layering, which is necessary for the existence of a waveguide, prompted additional work on the dune structure and stratigraphy. The current work highlights geophysical measurements at Eureka Dunes in Death Valley National Park, CA and Dumont Dunes in the Mojave Desert, CA. Seismic refraction studies indicate strong layering with large velocity jumps across the interfaces. Ground Penetrating Radar (GPR) profiles, at frequencies of 100 MHz and 200 MHz, map out the stratigraphic structure of the dunes. Variations in the near surface layering are able to predict the seasonal variability in booming frequency both quantitatively and qualitatively. The Kirchhoff migrated GPR profiles are superimposed on the local topography obtained with a laser rangefinder. The complex dune structure is resolved to a depth of over 30 meters for the 100 MHz antenna. The GPR profiles of the longitudinal Eureka dune display complex internal structures from old dune crests. Both slopes have slip faces at 30 degrees with parallel layering (< 2m) at the near surface. At the transverse Dumont dune the GPR profile exhibits strong parallel layering on the booming leeward slipface only. The shallower windward face features a remarkable tilted repetitive layering that cuts through the surface. At Dumont Dunes the layering on the leeward face explains the change in booming frequency between 70 - 95 Hertz in the period 2005 - 2008. The tilted layering structure of the shallow windward face prevents the formation of a waveguide and is never able to sustain the

  3. Conceptual analyses of extensible booms to support a solar sail

    NASA Technical Reports Server (NTRS)

    Crawford, R. F.; Benton, M. D.

    1977-01-01

    Extensible booms which could function as the diagonal spars and central mast of an 800 meter square, non-rotating Solar Sailing Vehicle were conceptually designed and analyzed. The boom design concept that was investigated is an extensible lattice boom which is stowed and deployed by elastically coiling and uncoiling its continuous longerons. The seven different free-span lengths in each spar which would minimize the total weights of the spars and mast were determined. Boom weights were calculated by using a semi-empirical formulation which related the overall weight of a boom to the weight of its longerons.

  4. Impacts on Dissipative Sonic Vacuum

    NASA Astrophysics Data System (ADS)

    Xu, Yichao; Nesterenko, Vitali

    We investigate the propagating compression bell shape stress waves generated by the strikers with different masses impacting the sonic vacuum - the discrete dissipative strongly nonlinear metamaterial with zero long wave sound speed. The metamaterial is composed of alternating steel disks and Nitrile O-rings. Being a solid material, it has exceptionally low speed of the investigated stress waves in the range of 50 - 74 m/s, which is a few times smaller than the speed of sound or shock waves in air generated by blast. The shape of propagating stress waves was dramatically changed by the viscous dissipation. It prevented the incoming pulses from splitting into trains of solitary waves, a phenomenon characteristic of the non-dissipative strongly nonlinear discrete systems when the striker mass is larger than the cell mass. Both high-speed camera images and numerical simulations demonstrate the unusual rattling behavior of the top disk between the striker and the rest of the system. The linear momentum and energy from the striker were completely transferred to the metamaterial. This strongly nonlinear dissipative metamaterial can be designed for the optimal attenuation of dynamic loads generated by impact or contact explosion. Author 1 wants to acknowledge the support provided by UCSD.

  5. Nano-booms — A new class of WIMP detectors

    NASA Astrophysics Data System (ADS)

    Drukier, A. K.; Fagaly, R. L.; Bielski, R.

    2014-07-01

    Weakly Interacting Massive Particles (WIMPs) can constitute a large fraction of the dark matter (DM) in the universe. The importance of coherent scattering and detection of annual modulation effect (AME), diurnal modulation effect (DME) and direction sensitive AME was documented. In particular, DAMA/NaI and DAMA/LIBRA have released data collected during 14 annual cycles, which support in model independent way, the presence of DM particles in the galactic halo. There is a clear evidence of AME signature in DAMA data. Recently, positive hints have also been reported by CoGeNT on AME signature in Ge, while CREST-II and CDMS-Si have published some events in excess of estimated background; these events are compatible with WIMP-like candidates. If these results would be analyzed all together in some WIMP scenario, one could derive: MDM < 10 GeV/c2. Current generation of detectors is far from being optimal or in some cases even reliable when MDM approaches 5 GeV/c2. We propose a detector, which can detect the direction of incoming WIMPs. This paper focus on a particular implementation of the new class of nano-explosive DM detectors. The local heating ignites an explosion, which release chemical energy stored in such a nano-grain. Use of two component nano-explosive permits to amplify the bolometric effect due to WIMP-candidates. The energy available becomes 100,000-fold larger than the energy initially deposited by DM candidate. This leads to a sonic-boom, which can be detected remotely. This new class of nano-explosive detectors may be especially important in detection of WIMPs with very low mass, say MDM = O(5 GeV/c2). We describe a configuration, which leads to explosive-triode, and permits detection of the direction of incoming WIMPs.

  6. Design and analysis of low boom concepts at Langley Research Center

    NASA Technical Reports Server (NTRS)

    Darden, Christine M.; Mack, Robert J.; Needleman, Kathy E.; Baize, Daniel G.; Coen, Peter G.; Barger, Raymond L.; Melson, N. Duane; Adams, Mary S.; Shields, Elwood W.; Mcgraw, Marvin E.

    1992-01-01

    The objective of the sonic boom research in the current High Speed Research Program is to ultimately make possible overland supersonic flight by a high speed civil transport. To accomplish this objective, it is felt that results in four areas must demonstrate that such a vehicle would be acceptable by the general public, by the airframers, and by the airlines. It should be demonstrated: (1) that some waveform shape has the possibility of being acceptable to the general public; (2) that the atmosphere would not totally destroy such a waveform during propagation; (3) that a viable airplane could be built which produces such a waveform; and (4) that any performance penalty suffered by a low boom aircraft would be counteracted by the economic benefit of overland supersonic flight. The work being done at LaRC is in support of the third element listed above--the area of configuration design. The initial part of the paper will give a review of the theory being used for configuration designs and discuss two theory validation models which were built and tested within the past two years. Discussion of the wind tunnel and theoretical results (linear theory and higher order methods) and their implications for future designs will be included.

  7. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT; ULTRASONIC AQUEOUS CLEANING SYSTEMS, SMART SONIC CORPORATION, SMART SONIC

    EPA Science Inventory

    This report is a product of the U.S. EPA's Environmental Technoloy Verification (ETV) Program and is focused on the Smart Sonics Ultrasonic Aqueous Cleaning Systems. The verification is based on three main objectives. (1) The Smart Sonic Aqueous Cleaning Systems, Model 2000 and...

  8. Production Well Performance Enhancement using Sonication Technology

    SciTech Connect

    Adewumi, Michael A; Ityokumbul, M Thaddeus; Watson, Robert W; Eltohami, Eltohami; Farias, Mario; Heckman, Glenn; Houlihan, Brendan; Karoor, Samata Prakash; Miller, Bruce G; Mohammed, Nazia; Olanrewaju, Johnson; Ozdemir, Mine; Rejepov, Dautmamed; Sadegh, Abdallah A; Quammie, Kevin E; Zaghloul, Jose; Hughes, W Jack; Montgomery, Thomas C

    2005-12-31

    The objective of this project was to develop a sonic well performance enhancement technology that focused on near wellbore formation damage. In order to successfully achieve this objective, a three-year project was defined. The entire project was broken into four tasks. The overall objective of all this was to foster a better understanding of the mechanisms involved in sonic energy interactions with fluid flow in porous media and adapt such knowledge for field applications. The fours tasks are: • Laboratory studies • Mathematical modeling • Sonic tool design and development • Field demonstration The project was designed to be completed in three years; however, due to budget cuts, support was only provided for the first year, and hence the full objective of the project could not be accomplished. This report summarizes what was accomplished with the support provided by the US Department of Energy. Experiments performed focused on determining the inception of cavitation, studying thermal dissipation under cavitation conditions, investigating sonic energy interactions with glass beads and oil, and studying the effects of sonication on crude oil properties. Our findings show that the voltage threshold for onset of cavitation is independent of transducer-hydrophone separation distance. In addition, thermal dissipation under cavitation conditions contributed to the mobilization of deposited paraffins and waxes. Our preliminary laboratory experiments suggest that waxes are mobilized when the fluid temperature approaches 40°C. Experiments were conducted that provided insights into the interactions between sonic wave and the fluid contained in the porous media. Most of these studies were carried out in a slim-tube apparatus. A numerical model was developed for simulating the effect of sonication in the nearwellbore region. The numerical model developed was validated using a number of standard testbed problems. However, actual application of the model for scale

  9. Laboratory testing of a flexible boom for ice management

    SciTech Connect

    Loeset, S. . Norwegian Hydrotechnical Lab.); Timco, G.W. )

    1993-08-01

    Combating oil spills in the Arctic is a major challenge. Drilling or producing oil or gas in the marginal ice zone (MIZ) may allow booms to be deployed upstream of an offshore structure to clear the water of ice, thereby enabling conventional oil spill countermeasures to be used. Such a boom would be kept in place by two ice-going service vessels or by moored buoys. SINTEF NHL and NRC have performed a number of small-scale tests with a flexible boom in the NRC ice basin in Ottawa. The purpose of the tests was to measure the effectiveness of using a flexible boom for collecting ice, and to determine the loads associated with collecting the ice. In the tests, various boom configurations were towed against a broken ice field consisting of ice pieces typically 50--100 mm across and 30 mm thick. The ice concentration was usually 10/10, but it was reduced to 8/10 and 5/10 for two tests. The boom was towed at speeds of 20 and 50 mm-s[sup [minus]1]. Both the width of the boom and the slackness of the boom were varied over reasonable ranges. Two six-component dynamometers were used to support the boom. Thus, the force components on each end of the boom were measured. Further, two video cameras were used to record the effectiveness of each boom configuration. In this paper, the full results of this test program are presented and the application of the test results to the full-scale situation are discussed. The tests show that, under certain conditions, the use of boom is feasible for ice management in oil-contaminated water.

  10. Sonic Combustion using One THz Radiation

    SciTech Connect

    Johansen, Donald G

    2004-03-30

    A model is presented for sonic region radiation-heated flow. Sonic combustion provides a direct and efficient heating method and can meet specific impulse and thrust requirements for orbital insertion and escape. The model allows investigation of flow geometry, real gas effects and stability issues using 1, 2 and 3-dimensional simulations. Concept feasibility, design optimization and trade studies are possible with this model. The paper introduces the concept of end-to-end simulation whereby computer modeling is used for all aspects of beamed energy propulsion from source through path to propulsion module.

  11. Development of the sonic pump levitator

    NASA Technical Reports Server (NTRS)

    Dunn, S. A.

    1985-01-01

    The process and mechanism involved in producing glass microballoons (GMBs) of acceptable quality for laser triggered inertial fusion through use of glass jet levitation and manipulation are considered. The gas jet levitation device, called sonic pumps, provides positioning by timely and appropriate application of gas mementum from one or more of six sonic pumps which are arranged orthogonally in opposed pairs about the levitation region and are activated by an electrooptical, computer controlled, feedback system. The levitation device was fabricated and its associated control systems were assembled into a package and tested in reduced gravity flight regime of the NASA KC-135 aircraft.

  12. Performance of floating oil booms in unsheltered waters

    NASA Astrophysics Data System (ADS)

    Iglesias, Gregorio; Castro, Alberte

    2013-04-01

    Oil booms are a fundamental tool to diminish the impact of an oil spill. They tend to perform reasonably well in sheltered waters, e.g. within a harbour. However, their performance is often inadequate in open water conditions, under waves, winds and currents. And it is precisely in those conditions that they are needed if oil slicks are to be prevented from reaching certain particularly sensitive areas, such as estuaries, rias, etc. (Castro et al., 2010; Iglesias et al., 2010). In this work the performance of floating oil booms under waves and currents is assessed on the basis of laboratory experiments carried out in a state-of-the-art wave-current flume. Different oil boom models are used, representative of booms with long and short skirts and with different weights. The results show that different booms behave very differently under waves and currents, hence the importance of selecting the boom design that is appropriate for the actual conditions under which it will have to contain the oil slick. Thus, different oil booms should be used for different areas. References A. Castro, G. Iglesias, R. Carballo, J.A. Fraguela, 2010. Floating boom performance under waves and currents, Journal of Hazardous Materials 174, 226-235 G. Iglesias, A.Castro, J.A.Fraguela, 2010. Artificial intelligence applied to floating boom behavior under waves and currents, Ocean Engineering 37, 1513-1521.

  13. [Building and testing of Pickard Line-up Boom

    SciTech Connect

    Not Available

    1992-01-01

    The Packard Line-up Boom is a device for controlling the placing together of the ends of two sections of pipe for clamping and welding. Consistently better weld quality is possible because the optimum weld space is achieved and held constant throughout every stringer bead, regardless of the welding method. With the use of the Pickard Line-Up Boom, there will be a minimum of pipe movement while the stringer bead is being run. Since the welder can rely on conditions being the same throughout the weld, he can regulate the weld to eliminate backwelding almost entirely. During the grant period and with the assistance of DOE grant funds, Pickard Line-up Boom Associates (PLUBA) successfully completed Task 1, construction of the Packard Boom. PLUBA contracted with Sawyer Manufacturing Company (1031 North Columbia Place, Tulsa, Oklahoma) to construct the new boom. After completion of the new boom by Sawyer, the boom was successfully tested by PLUBA, thereafter PLUBA attempted to obtain lease agreements with pipeline contractors (Tasks 2 and 3). Toward the end of the project period, PLUBA entered into a license/marketing agreement with Sabre International with. the objective of first securing contracts outside of the United States. Once this is achieved and the Packard Boom is used successfully in the field, it is believed that pipeline contractors may be more willing to use the Packard Boom in the United States.

  14. Quantifying Snow Transport Using Snow Fences and Sonic Sensors

    NASA Astrophysics Data System (ADS)

    Sturm, M.; Berezovskaya, S.; Hiemstra, C.; Gelvin, A.

    2010-12-01

    Accurate assessment of snow transport (T) during wind events is a prerequisite to reliable estimation of snow loads on infrastructure and prediction of avalanche danger in the mountains. It is also a critical term in the winter water balance, affecting snow sublimation. To assess T we constructed two snow fences in northern Alaska and used an existing municipal fence near Barrow, Alaska to trap the wind-blown flux of snow. On the leeward side of each fence we installed a line of SR50 sonic ranging sensors that could be used to track the increase in snow height with time. We also installed web-cameras to monitor changes in drift shape. Periodic snow surface elevation surveys using a DGPS system provided more detailed drift profiles during the winter. Wind speed and direction were monitored near the fences. The sonic sensor results have been combined with the DGPS surveys to produce a time series of drift cross-section from which the flux has been computed. We have related this flux to individual wind events in an effort to identify the optimal conditions for blowing snow transport and to derive an empirical expression for T from weather measurements.

  15. Particle-Molecule Collection by Sonic Flow Impingers

    ERIC Educational Resources Information Center

    Jackson, Melbourne L.

    1974-01-01

    The theoretical basis of the sonic-flow impinger is discussed. Details are given for the design, prediction of performance, preliminary evaluation for particle collection, and field use of a sonic-flow impinger train. (DT)

  16. Generation of sonic power during welding

    NASA Technical Reports Server (NTRS)

    Mc Campbell, W. M.

    1969-01-01

    Generation of intense sonic and ultrasonic power in the weld zone, close to the puddle, reduces the porosity and refinement of the grain. The ac induction brazing power supply is modified with long cables for deliberate addition of resistance to that circuit. The concept is extensible to the molding of metals and plastics.

  17. Evaluation of fracture strength by sonic testing

    SciTech Connect

    Kennedy, C.R.

    1981-01-01

    The Griffith-Irwin equation is used to describe the fracture characteristics of graphite. The material constants, Young's modulus and mean flaw size, are measured sonically from velocity and attenuation measurements. The effects of steam oxidation and neutron irradiation on fracture strength are shown to be predictable assuming a constant strain-energy release rate.

  18. The Sound of Stigmatization: Sonic Habitus, Sonic Styles, and Boundary Work in an Urban Slum.

    PubMed

    Schwarz, Ori

    2015-07-01

    Based on focus groups and interviews with student renters in an Israeli slum, the article explores the contributions of differences in sonic styles and sensibilities to boundary work, social categorization, and evaluation. Alongside visual cues such as broken windows, bad neighborhoods are characterized by sonic cues, such as shouts from windows. Students understand "being ghetto" as being loud in a particular way and use loudness as a central resource in their boundary work. Loudness is read as a performative index of class and ethnicity, and the performance of middle-class studentship entails being appalled by stigmatized sonic practices and participating in their exoticization. However, the sonic is not merely yet another resource of boundary work. Paying sociological attention to senses other than vision reveals complex interactions between structures anchored in the body, structures anchored in language, and actors' identification strategies, which may refine theorizations of the body and the senses in social theory. PMID:26430711

  19. The GEOS-20 m Cable Boom Mechanism

    NASA Technical Reports Server (NTRS)

    Schmidt, G. K.; Suttner, K.

    1977-01-01

    The GEOS Cable Boom Mechanism which allows the controlled deployment of a 20 m long cable in a centrifugal force field is described. In launch configuration the flat cable is reeled on a 240 mm diameter drum. The electrical connection between the rotating drum and the stationary housing is accomplished via a flexlead positioned inside the drum. Active motion control of this drum is achieved by a self locking worm gear, driven by a stepper motor. The deployment length of the cable is monitored by an optical length indicator, sensing black bars engraved on the cable surface.

  20. GEOS-20 m cable boom mechanism

    NASA Technical Reports Server (NTRS)

    Schmidt, B. K.; Suttner, K.

    1977-01-01

    The GEOS cable boom mechanism allows the controlled deployment of a 20 m long cable in a centrifugal force field. In launch configuration the flat cable is reeled on a 240 mm diameter drum. The electrical connection between the rotating drum and the stationary housing is accomplished via a flexlead positioned inside the drum. Active motion control of this drum is achieved by a self locking worm gear, driven by a stepper motor. The deployment length of the cable is monitored by an optical length indicator, sensing black bars engraved on the cable surface.

  1. Sonic morphology: Aesthetic dimensional auditory spatial awareness

    NASA Astrophysics Data System (ADS)

    Whitehouse, Martha M.

    The sound and ceramic sculpture installation, " Skirting the Edge: Experiences in Sound & Form," is an integration of art and science demonstrating the concept of sonic morphology. "Sonic morphology" is herein defined as aesthetic three-dimensional auditory spatial awareness. The exhibition explicates my empirical phenomenal observations that sound has a three-dimensional form. Composed of ceramic sculptures that allude to different social and physical situations, coupled with sound compositions that enhance and create a three-dimensional auditory and visual aesthetic experience (see accompanying DVD), the exhibition supports the research question, "What is the relationship between sound and form?" Precisely how people aurally experience three-dimensional space involves an integration of spatial properties, auditory perception, individual history, and cultural mores. People also utilize environmental sound events as a guide in social situations and in remembering their personal history, as well as a guide in moving through space. Aesthetically, sound affects the fascination, meaning, and attention one has within a particular space. Sonic morphology brings art forms such as a movie, video, sound composition, and musical performance into the cognitive scope by generating meaning from the link between the visual and auditory senses. This research examined sonic morphology as an extension of musique concrete, sound as object, originating in Pierre Schaeffer's work in the 1940s. Pointing, as John Cage did, to the corporeal three-dimensional experience of "all sound," I composed works that took their total form only through the perceiver-participant's participation in the exhibition. While contemporary artist Alvin Lucier creates artworks that draw attention to making sound visible, "Skirting the Edge" engages the perceiver-participant visually and aurally, leading to recognition of sonic morphology.

  2. 12. BOOM, FROM SUPERSTRUCTURE DECK (ABOVE WINCH ROOM), SHOWING DETAIL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. BOOM, FROM SUPERSTRUCTURE DECK (ABOVE WINCH ROOM), SHOWING DETAIL OF GEARED WHEEL OF BOOM, FLYBRIDGE AT LEFT. - U.S. Coast Guard Cutter WHITE LUPINE, U.S. Coast Guard Station Rockland, east end of Tillson Avenue, Rockland, Knox County, ME

  3. Baby Boom Equals Career Bust. Monographs on Career Education.

    ERIC Educational Resources Information Center

    Moore, Charles Guy

    Presenting the Baby Boom (1946-1965) as both a potential social problem and opportunity for American leadership, this monograph discusses the following aspects of this population concern: (1) its immediate and long-term impact on career opportunities for those college graduates who make up the baby boom generation; (2) its impact on those whose…

  4. A RIGID, PERFORATED PLATE OIL BOOM FOR HIGH CURRENTS

    EPA Science Inventory

    A boom capable of diverting oil spills toward shore in a 3-knot (1.5 m/s) river or tidal current has been developed. Loss of No. 2 and No. 4 Fuel Oil at this velocity is typically less than 15 percent when the angle of the boom is 45 degrees to the shoreline. In contrast, convent...

  5. Uncertainty Quantification and Certification Prediction of Low-Boom Supersonic Aircraft Configurations

    NASA Technical Reports Server (NTRS)

    West, Thomas K., IV; Reuter, Bryan W.; Walker, Eric L.; Kleb, Bil; Park, Michael A.

    2014-01-01

    The primary objective of this work was to develop and demonstrate a process for accurate and efficient uncertainty quantification and certification prediction of low-boom, supersonic, transport aircraft. High-fidelity computational fluid dynamics models of multiple low-boom configurations were investigated including the Lockheed Martin SEEB-ALR body of revolution, the NASA 69 Delta Wing, and the Lockheed Martin 1021-01 configuration. A nonintrusive polynomial chaos surrogate modeling approach was used for reduced computational cost of propagating mixed, inherent (aleatory) and model-form (epistemic) uncertainty from both the computation fluid dynamics model and the near-field to ground level propagation model. A methodology has also been introduced to quantify the plausibility of a design to pass a certification under uncertainty. Results of this study include the analysis of each of the three configurations of interest under inviscid and fully turbulent flow assumptions. A comparison of the uncertainty outputs and sensitivity analyses between the configurations is also given. The results of this study illustrate the flexibility and robustness of the developed framework as a tool for uncertainty quantification and certification prediction of low-boom, supersonic aircraft.

  6. Noise and sonic-boom impact technology. PCBOOM computer program for sonic-boom research. Volume 2. Program users/computer operations manual. Final report, May 1987-October 1988

    SciTech Connect

    Salvetti, A.; Seidman, H.

    1988-10-01

    This report contains the information for both the user and for computer operations. The report provides the user with the information necessary to effectively use PCBOOM. In addition, it provides the computer operations personnel with a description of the computer system and its associated environment. Two other reports provide a technical discussion of the algorithms used and a program maintenance manual.

  7. Laser needle guide for the sonic flashlight.

    PubMed

    Wang, David; Wu, Bing; Stetten, George

    2005-01-01

    We have extended the real-time tomographic reflection display of the Sonic Flashlight to a laser guidance system that aims to improve safety and accuracy of needle insertion, especially for deep procedures. This guidance system is fundamentally different from others currently available. Two low-intensity lasers are mounted on opposite sides of a needle aimed parallel to the needle. The needle is placed against a notch in the Sonic Flashlight mirror such that the laser beams reflect off the mirror to create bright red spots on the flat panel display. Due to diffuse reflection from these spots, the virtual image created by the flat panel display contains the spots, identifying the projected destination of the needle at its actual location in the tissue. We have implemented our design and validated its performance, identifying several areas for potential improvement. PMID:16685901

  8. Sonic Temperature Sensor for Food Processing

    SciTech Connect

    Akers, D. W.; Porter, A. M.; Tow, D. M.

    1997-09-01

    The lack of adequate temperature measurement is the major barrier to the development of more efficient and better quality food processing methods. The objective of the sonic temperature sensor for food processing project is to develop a prototype sensor system to noninvasively measure the interior temperature of particulate foods during processing. The development of the prototype sensor is a collaborative project with the National Food Processors Association. The project is based on the property of materials that involves a change in the temperature of a material having a corresponding change in the speed of sound. The approach for the sonic sensor system is to determine the speed of sound through particulate foods using a tomographic reconstruction process.

  9. Brazil's sugarcane boom could affect regional temperatures

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-04-01

    With the world seeking to cut its dependence on fossil fuels, the use of bioethanol and other biofuels is on the rise. In Brazil, the second largest producer and consumer of bioethanol, this has led to a boom in sugarcane production. Based on new laws and trade agreements, researchers expect Brazil's production of sugarcane-derived ethanol to increase tenfold over the next decade, with considerable land being converted for growing sugarcane. Much of this expansion is expected to come at a loss of some of the country's cerrado savannas. So while a major aim of the turn to biofuels is to reduce the transfer of carbon to the atmosphere and mitigate global climate change, the shifting agricultural activity could have direct consequences on Brazil's climate by changing the region's physical and biogeochemical properties.

  10. Continuous subsonic-sonic flows in a general nozzle

    NASA Astrophysics Data System (ADS)

    Wang, Chunpeng

    2015-10-01

    This paper concerns continuous subsonic-sonic potential flows in a two dimensional finite nozzle with a general upper wall and a straight lower wall. We give a class of nozzles where continuous subsonic-sonic flows may exist. Consider a continuous subsonic-sonic flow in such a nozzle after rescaling the upper wall in a small scale. It is shown that for a given inlet and a fixed point at the upper wall, there exists uniquely a continuous subsonic-sonic flow whose velocity vector is along the normal direction at the inlet and the sonic curve, which satisfies the slip conditions on the nozzle walls and whose sonic curve intersects the upper wall at the fixed point. Furthermore, the sonic curve of this flow is a free boundary, where the flow is singular in the sense that the speed is only C 1 / 2 Hölder continuous and the acceleration blows up at the sonic state. As the scale tends to zero, the precise convergent rate of the continuous subsonic-sonic flow converging to the sonic state is also determined.

  11. Study of a 30-M Boom For Solar Sail-Craft: Model Extendibility and Control Strategy

    NASA Technical Reports Server (NTRS)

    Keel, Leehyun

    2005-01-01

    Space travel propelled by solar sails is motivated by the fact that the momentum exchange that occurs when photons are reflected and/or absorbed by a large solar sail generates a small but constant acceleration. This acceleration can induce a constant thrust in very large sails that is sufficient to maintain a polar observing satellite in a constant position relative to the Sun or Earth. For long distance propulsion, square sails (with side length greater than 150 meters) can reach Jupiter in two years and Pluto in less than ten years. Converting such design concepts to real-world systems will require accurate analytical models and model parameters. This requires extensive structural dynamics tests. However, the low mass and high flexibility of large and light weight structures such as solar sails makes them unsuitable for ground testing. As a result, validating analytical models is an extremely difficult problem. On the other hand, a fundamental question can be asked. That is whether an analytical model that represents a small-scale version of a solar-sail boom can be extended to much larger versions of the same boom. To answer this question, we considered a long deployable boom that will be used to support the solar sails of the sail-craft. The length of fully deployed booms of the actual solar sail-craft will exceed 100 meters. However, the test-bed we used in our study is a 30 meter retractable boom at MSFC. We first develop analytical models based on Lagrange s equations and the standard Euler-Bernoulli beam. Then the response of the models will be compared with test data of the 30 meter boom at various deployed lengths. For this stage of study, our analysis was limited to experimental data obtained at 12ft and 18ft deployment lengths. The comparison results are positive but speculative. To observe properly validate the analytic model, experiments at longer deployment lengths, up to the full 30 meter, have been requested. We expect the study to answer the

  12. Assimilation of Sonic Velocity and Thin Section Measurements from the NEEM Ice Core

    NASA Astrophysics Data System (ADS)

    Hay, Michael; Pettit, Erin; Kluskiewicz, Dan; Waddington, Edwin

    2016-04-01

    We examine the measurement of crystal orientation fabric (COF) in ice cores using thin sections and sound-wave velocities, focusing on the NEEM core in Greenland. Ice crystals have substantial plastic anisotropy, with shear orthogonal to the crystallographic c-axis occuring far more easily than deformation in other orientations. Due to strain-induced grain-rotation, COFs can become highly anisotropic, resulting in bulk anisotropic flow. Thin-section measurements taken from ice cores allow sampling of the crystal fabric distribution. Thin-section measurements, however, suffer from sampling error, as they sample a small amount of ice, usually on the order of a hundred grans. They are typically only taken at intervals of several meters, which means that meter-scale variations in crystal fabric are difficult to capture. Measuring sonic velocities in ice cores provides an alternate method of determining crystal fabric. The speed of vertical compression waves is affected by the vertical clustering of c-axes, but is insensitive to azimuthal fabric anisotropy. By measuring splitting between the fast and slow shear-wave directions, information on the azimuthal distribution of orientations can be captured. Sonic-velocity measurements cannot capture detailed information on the orientation distribution of the COF, but they complement thin-section measurements with several advantages. Sonic-logging measurements can be taken at very short intervals, eliminating spatial gaps. In addition, sonic logging samples a large volume of ice with each measurement, reducing sampling error. Our logging tool has a depth resolution of around 3m/s, and can measure velocity features on the order of 1m/s. Here, we show the results of compression-wave measurements at NEEM. We also combine sonic-velocity measurements and thin-section measurements to produce a more accurate and spatially-complete representation of ice-crystal orientations in the vicinity of the NEEM core.

  13. Effect of sonication on eliminating of phorate in apple juice.

    PubMed

    Zhang, Yuanyuan; Zhang, Zhe; Chen, Fang; Zhang, Hui; Hu, Xiaosong

    2012-01-01

    The degradation of phorate in apple juice by sonication was investigated in the present study. Results showed that sonication was effective in eliminating phorate in apple juice, and the ultrasonic power and sonication time significantly influenced the degradation of phorate (p<0.05). The degradation of phorate followed the first-order kinetics model well. Phorate-oxon and phorate sulfoxide were identified as the degradation products of phorate by gas chromatography-mass spectrometry (GC-MS). Moreover, the toxicity of apple juice samples spiked with phorate was significantly reduced by sonication (p<0.05). The quality indexes of apple juice including pH, titratable acidity (TA), electrical conductivity (EC), total soluble solids (TSS), and the contents of sucrose, glucose and fructose were not affected by sonication, and no visible difference in color was observed between the sonicated samples and the control. PMID:21669544

  14. 12. BOOM, FROM SUPERSTRUCTURE DECK (ABOVE WINCH ROOM), LOOKING TOWARDS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. BOOM, FROM SUPERSTRUCTURE DECK (ABOVE WINCH ROOM), LOOKING TOWARDS BOW. - U.S. Coast Guard Cutter WHITE HEATH, USGS Integrated Support Command Boston, 427 Commercial Street, Boston, Suffolk County, MA

  15. 13. DETAIL OF BOOM'S GEARED WHEEL, FROM SUPERSTRUCTURE DECK (ABOVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. DETAIL OF BOOM'S GEARED WHEEL, FROM SUPERSTRUCTURE DECK (ABOVE WINCH ROOM), FLYBRIDGE IS AT LEFT. - U.S. Coast Guard Cutter WHITE HEATH, USGS Integrated Support Command Boston, 427 Commercial Street, Boston, Suffolk County, MA

  16. 14. FLYBRIDGE, LOOKING TOWARDS PORT, SHOWING BOOM CONTROLS, PILOT HOUSE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. FLYBRIDGE, LOOKING TOWARDS PORT, SHOWING BOOM CONTROLS, PILOT HOUSE AT LEFT. - U.S. Coast Guard Cutter WHITE HEATH, USGS Integrated Support Command Boston, 427 Commercial Street, Boston, Suffolk County, MA

  17. 9. PERSPECTIVE OF THE BOOMS, SHOWING THE MANNER IN WHICH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. PERSPECTIVE OF THE BOOMS, SHOWING THE MANNER IN WHICH STONE WAS HOISTED UPON THE PIER AFTER REMOVAL OF THE DERRICKS. - Potomac Aqueduct, Spanning Potomac River, Washington, District of Columbia, DC

  18. World's Senior Population Forecast to Boom by 2050

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_157999.html World's Senior Population Forecast to Boom by 2050 Public ... 28, 2016 (HealthDay News) -- The percentage of the world's population aged 65 and older is expected to ...

  19. 1. Distant view of mill ruins with boom crane for ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Distant view of mill ruins with boom crane for unloading sugar cane in foreground, looking W. - Laurel Valley Sugar Plantation, Sugar Mill, 2 miles South of Thibodaux on State Route 308, Thibodaux, Lafourche Parish, LA

  20. 14. Photocopy of c. 1906 photograph of 70 foot boom ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Photocopy of c. 1906 photograph of 70 foot boom crane that unloaded the sugar cane. - Laurel Valley Sugar Plantation, Sugar Mill, 2 miles South of Thibodaux on State Route 308, Thibodaux, Lafourche Parish, LA