Particle trajectory computation on a 3-dimensional engine inlet. Final Report Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Kim, J. J.

1986-01-01

A 3-dimensional particle trajectory computer code was developed to compute the distribution of water droplet impingement efficiency on a 3-dimensional engine inlet. The computed results provide the essential droplet impingement data required for the engine inlet anti-icing system design and analysis. The droplet trajectories are obtained by solving the trajectory equation using the fourth order Runge-Kutta and Adams predictor-corrector schemes. A compressible 3-D full potential flow code is employed to obtain a cylindrical grid definition of the flowfield on and about the engine inlet. The inlet surface is defined mathematically through a system of bi-cubic parametric patches in order to compute the droplet impingement points accurately. Analysis results of the 3-D trajectory code obtained for an axisymmetric droplet impingement problem are in good agreement with NACA experimental data. Experimental data are not yet available for the engine inlet impingement problem analyzed. Applicability of the method to solid particle impingement problems, such as engine sand ingestion, is also demonstrated.

Numerical modelling to assess maintenance strategy management options for a small tidal inlet

NASA Astrophysics Data System (ADS)

Shaeri, Saeed; Tomlinson, Rodger; Etemad-Shahidi, Amir; Strauss, Darrell

2017-03-01

Small tidal inlets are found to be more sensitive to anthropogenic alteration than their larger counterparts. Such alterations, although typically supported by technical design reports, sometimes require amendments or modification. One of the most suitable tools to conduct the necessary studies in this regard is numerical modelling, since the behaviour of the inlet system in response to proposed remedial actions, can easily be identified. In this paper, various alternative proposals are investigated to determine the most practical and viable option to mitigate the need for ongoing maintenance at a typical small, jettied tidal inlet. The main tool to investigate the alternatives is the hydro-sedimentological modelling of the inlet system, which was performed using the Delft3D software package. The proposed alternative entrance modifications were based upon structural alterations of the inlet system (such as a jetty extension or submerged weir) and non-structural scenarios (such as a change of the time of the dredging campaign or the deposition location of the dredged material). It was concluded that whilst a detailed study is inevitable in order to achieve a comprehensive design plan, based upon the results of this study the construction of a submerged weir at the entrance channel can satisfy the needs of most of the stakeholders, with justifiable costs over a longer period.

An Investigation of Single- and Dual-Rotation Propellers at Positive and Negative Thrust, and in Combination with an NACA 1-series D-Type Cowling at Mach Numbers up to 0.84

NASA Technical Reports Server (NTRS)

Reynolds, Robert M; Samonds, Robert I; Walker, John H

1957-01-01

An investigation has been made to determine the aerodynamic characteristics of the NACA 4-(5)(05)-041 four-blade, single-relation propeller and the NACA 4-(5)(05)-037 six- and eight-blade, dual-rotation propellers in combination with various spinners and NACA d-type spinner-cowling combinations at Mach numbers up to 0.84. Propeller force characteristics, local velocity distributions in the propeller planes, inlet pressure recoveries, and static-pressure distributions on the cowling surfaces were measured for a wide range of blade angles, advance ratios, and inlet-velocity ratios. Included are data showing: (a) the effect of extended cylindrical spinners on the characteristics of the single-rotation propeller, (b) the effect of variation of the difference in blade angle setting between the front and rear components of the dual-rotation propellers, (c) the negative- and static-thrust characteristics of the propellers with 1 series spinners, and (d) the effects of ideal- and platform-type propeller-spinner junctures on the pressure-recovery characteristics of the single-rotation propeller-spinner-cowling combination.

Complete NACA Muroc Staff of 1954, in front of new NACA building (4800)

NASA Technical Reports Server (NTRS)

1954-01-01

The employees of the NACA High-Speed Flight Station are gathered for a 1954 photo shoot on the front steps of building 4800, the new NACA Facility at Main Base of Edwards Air Force Base, California. This new building was considerably larger than the earlier NACA buildings on South Base, but then the staff had increased and the extra space was needed. From 1950 when an earlier group picture was taken (E-33717) until 1954 the staff at NACA increased from 132 to 250. As the workload increased and more research flights were completed the complement of employees grew to 662 in 1966. More changes took place in 1954 with the Station being called the NACA High-Speed Flight Station. A further name change occurred in October 1958 to the National Aeronautics and Space Administration (NASA) High-Speed Flight Station and again in September 1959 to the NASA Flight Research Center. There would be two more name changes before the next group photo (EC85-33160-2) would be made. On March 1976 to NASA Hugh L. Dryden Flight Research Center and in October 1981 when the Center became the Ames-Dryden Flight Research Facility.

NACA Groundbreaking Ceremony

NASA Technical Reports Server (NTRS)

1953-01-01

The NACA High-Speed Flight Research Station, had initially been subordinate to the Langley Memorial Aeronautical Laboratory near Hampton, Virginia, but as the flight research in the Mojave Desert increasingly proved its worth after 1946, it made sense to make the Flight Research Station a separate entity reporting directly to the headquarters of the National Advisory Committee for Aeronautics. But an autonomous center required all the trappings of a major research facility, including good quarters. With the adoption of the Edwards 'Master Plan,' the Air Force had committed itself to moving from its old South Base to a new location midway between the South and North Bases. The NACA would have to move also--so why not take advantage of the situation and move into a full-blown research facility. The Air Force issued a lease to NACA for a location on the northwestern shore of the Roger Dry Lake. Construction started on the NACA station in early February 1953. On a windy day, January 27, 1953, at a groundbreaking ceremony stood left to right: Gerald Truszynski, Head of Instrumentation Division; Joseph Vensel, Head of the Operations Branch; Walter Williams, Head of the Station, scooping the first shovel full of dirt; Marion Kent, Head of Personnel; and California state official Arthur Samet.

Coordinating Council. Fourth Meeting: NACA Documents Database Project

NASA Technical Reports Server (NTRS)

1991-01-01

This NASA Scientific and Technical Information Coordination Council meeting dealt with the topic 'NACA Documents Database Project'. The following presentations were made and reported on: NACA documents database project study plan, AIAA study, the Optimal NACA database, Deficiencies in online file, NACA documents: Availability and Preservation, the NARA Collection: What is in it? and What to do about it?, and NACA foreign documents and availability. Visuals are available for most presentations.

Investigation of Aerodynamic and Icing Characteristics of a Flush Alternate Inlet Induction System Air Scoop

NASA Technical Reports Server (NTRS)

Lewis, James P.

1953-01-01

An investigation has been made in the NACA Lewis icing research tunnel to determine the aerodynamic and icing characteristics of a full-scale induction-system air-scoop assembly incorporating a flush alternate inlet. The flush inlet was located immediately downstream of the offset ram inlet and included a 180 deg reversal and a 90 deg elbow in the ducting between inlet and carburetor top deck. The model also had a preheat-air inlet. The investigation was made over a range of mass-air- flow ratios of 0 to 0.8, angles of attack of 0 and 4 deg airspeeds of 150 to 270 miles per hour, air temperatures of 0 and 25 F various liquid-water contents, and droplet sizes. The ram inlet gave good pressure recovery in both clear air and icing but rapid blockage of the top-deck screen occurred during icing. The flush alternate inlet had poor pressure recovery in both clear air and icing. The greatest decreases in the alternate-inlet pressure recovery were obtained at icing conditions of low air temperature and high liquid-water content. No serious screen icing was observed with the alternate inlet. Pressure and temperature distributions on the carburetor top deck were determined using the preheat-air supply with the preheat- and alternate-inlet doors in various positions. No screen icing occurred when the preheat-air system was operated in combination with alternate-inlet air flow.

NACA Researcher Examines the Cyclotron

NASA Image and Video Library

1951-02-21

Researcher James Blue examines the new cyclotron at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. Researchers at NACA Lewis began postulating about the use of atomic power for propulsion immediately after World War II. The NACA concentrated its efforts on the study of high temperature materials and heat transfer since it did not have access to the top secret fission information. The military studied the plausibility of nuclear propulsion for aircraft in the late 1940s. The military program was cancelled after four years without any breakthroughs, but the Atomic Energy Commission took on the effort in 1951. The NACA Lewis laboratory was expanding its nuclear-related research during this period. In 1948, Lewis engineers were assigned to the Oak Ridge National Laboratory to obtain expertise in high temperature heat transfer and advanced materials technology. The following year a new 80-person Nuclear Reactor Division was created, and an in-house nuclear school was established to train these researchers. The cyclotron was built behind the Materials and Structures Laboratory to support thermodynamic and materials research for both nuclear aircraft and nuclear rockets. The original NACA Lewis cyclotron was used to accelerate two kinds of particles. To better match the space radiation environment, the cyclotron was later modified to accelerate particles of the newly-discovered Van Allen radiation belts.

An Experimental Investigation of Flow Conditions in the Vicinity of an NACA D(sub S)-type Cowling

NASA Technical Reports Server (NTRS)

Bryant, Rosemary P.; Boswinkle, Robert W.

1946-01-01

Data are presented of the flow conditions in the vicinity of an NACA D sub S -type cowling. Tests were made of a 1/2 scale-nacelle model at inlet-velocity ratios ranging from 0.23 to 1.02 and angles of attack from 6 deg to 10 deg. The velocity and direction of flow in the vertical plane of symmetry of the cowling were determined from orifices and tufts installed on a board aligned with the flow. Diagrams showing velocity ratio contours and lines of constant flow angles are given.

Electrogenic Na+/Ca2+ Exchange

PubMed Central

Danaceau, Jonathan P.; Lucero, Mary T.

2000-01-01

Olfactory receptor neurons (ORNs) from the squid, Lolliguncula brevis, respond to the odors l-glutamate or dopamine with increases in internal Ca2+ concentrations ([Ca2+]i). To directly asses the effects of increasing [Ca2+]i in perforated-patched squid ORNs, we applied 10 mM caffeine to release Ca2+ from internal stores. We observed an inward current response to caffeine. Monovalent cation replacement of Na+ from the external bath solution completely and selectively inhibited the caffeine-induced response, and ruled out the possibility of a Ca2+-dependent nonselective cation current. The strict dependence on internal Ca2+ and external Na+ indicated that the inward current was due to an electrogenic Na+/Ca2+ exchanger. Block of the caffeine-induced current by an inhibitor of Na+/Ca2+ exchange (50–100 μM 2′,4′-dichlorobenzamil) and reversibility of the exchanger current, further confirmed its presence. We tested whether Na+/Ca2+ exchange contributed to odor responses by applying the aquatic odor l-glutamate in the presence and absence of 2′,4′-dichlorobenzamil. We found that electrogenic Na+/Ca2+ exchange was responsible for ∼26% of the total current associated with glutamate-induced odor responses. Although Na+/Ca2+ exchangers are known to be present in ORNs from numerous species, this is the first work to demonstrate amplifying contributions of the exchanger current to odor transduction. PMID:10828249

NACA Wartime Safety Poster

NASA Image and Video Library

1945-04-21

One of many safety posters produced by NACA artists during World War II. The Aircraft Engine Research Laboratory established a Safety Office in 1942 to coordinate and oversee safety-related activities. The lab struggled to maintain a full staff during the war when military research projects were at a peak. NACA management mandated six-day work weeks without overtime and the elimination of holidays. As such, workplace injuries were a serious threat to maintaining productivity needed to sustain the military’s aeronautics efforts.

2015 Summer Series - The NACA - A Hundred Year Legacy

NASA Image and Video Library

2015-07-09

Understanding the past provides insight into our identity and NASA's history lies within NACA, the National Advisory Committee for Aeronautics. NACA's culture of conducting cutting edge research became the spirit of NASA and laid the foundation for America's leap into space. NACA was established on March 3, 1915 in order to promote aeronautical research and was the source behind our air superiority during WWII. The Panel delves into the legacy of the NACA.

Selected bibliography of NACA-NASA aircraft icing publications

NASA Technical Reports Server (NTRS)

Reinmann, J. J. (Compiler)

1981-01-01

A summary of NACA-NASA icing research from 1940 to 1962 is presented. It includes: the main results of the NACA icing program from 1940 to 1950; a selected bibliography of 132 NACA-NASA aircraft icing publications; a technical summary of each document cited in the selected bibliography; and a microfiche copy of each document cited in the selected bibliography.

Rocket Research Presentation at the NACA's 1947 Inspection

NASA Image and Video Library

1947-10-21

Researcher John Sloop briefs visitors on his latest rocket engine research during the 1947 Inspection at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The NACA had been hosting annual Aircraft Engineering Conferences, better known as Inspections, since 1926. Individuals from the manufacturing industry, military, and university settings were invited to tour the NACA laboratories. There were a series of stops on the tour, mostly at test facilities, where researchers would brief the group on the latest efforts in their particular field. The Inspections grew in size and scope over the years and by the mid-1940s required multiple days. The three-day 1947 Inspection was the first time the event was held at NACA Lewis. Over 800 scientists, industrialists, and military leaders attended the three-day event. Talks were given at the Altitude Wind Tunnel, Four Burner Area, Engine Research Building, and other facilities. An array of topics were discussed, including full-scale engine testing, ramjets, axial-flow compressors, turbojets, fuels, icing, and materials. The NACA Lewis staff and their families were able to view the same presentations after the Inspection was over. Sloop, a researcher in the Fuels and Thermodynamics Division, briefed visitors on NACA Lewis’ early research in rocket engine propellants, combustion, and cooling. This early NACA Lewis work led to the development of liquid hydrogen as a viable propellant in the late 1950s.

Experimental Water Droplet Impingement Data on Airfoils, Simulated Ice Shapes, an Engine Inlet and a Finite Wing

NASA Technical Reports Server (NTRS)

Papadakis, M.; Breer, M.; Craig, N.; Liu, X.

1994-01-01

An experimental method has been developed to determine the water droplet impingement characteristics on two- and three-dimensional aircraft surfaces. The experimental water droplet impingement data are used to validate particle trajectory analysis codes that are used in aircraft icing analyses and engine inlet particle separator analyses. The aircraft surface is covered with thin strips of blotter paper in areas of interest. The surface is then exposed to an airstream that contains a dyed-water spray cloud. The water droplet impingement data are extracted from the dyed blotter paper strips by measuring the optical reflectance of each strip with an automated reflectometer. Experimental impingement efficiency data represented for a NLF (1)-0414 airfoil, a swept MS (1)-0317 airfoil, a Boeing 737-300 engine inlet model, two simulated ice shapes and a swept NACA 0012 wingtip. Analytical impingement efficiency data are also presented for the NLF (1)-0414 airfoil and the Boeing 737-300 engine inlet model.

A restored NACA P-51D Mustang in flight

NASA Image and Video Library

2000-09-15

A white plate on the top of the wing of a restored National Advisory Committee for Aeronautics (NACA) P-51D Mustang mounts scale airfoil shapes as used by the NACA in the late 1940s for high-speed research. This former NACA testbed Mustang was rebuilt by John Muszala for Bill Allmon of Las Vegas, Nevada, who has been flying it since 1998. Allmon flew the vintage fighter to NASA's Dryden Flight Research Center at Edwards, California, Sept. 15, 2000 for a reunion of former NACA employees.

NACA Subcommittee on Combustion Meeting

NASA Image and Video Library

1951-12-21

The National Advisory Committee for Aeronautics (NACA) Subcommittee on Combustion holds a meeting at Lewis Flight Propulsion Laboratory in Cleveland, Ohio. The NACA was managed by committees that included members of their own staff along with representatives from industry, the military, other government agencies, and universities. The 17-person Executive Committee was the NACA’s primary administrative body. They met several times a year at the NACA headquarters office in Washington DC to discuss broad issues confronting the US aeronautical community. Jerome Hunsaker, head of the Department of Aeronautical Engineering at the Massachusetts Institute of Technology, served as the NACA chairman from 1941 to 1956. George Lewis was not a member of the Executive Committee but served a key role as the NACA’s Director of Aeronautical Research. The NACA’s organizational chart also included 11 technical committees, several of which had specialized subcommittees. There were over 100 different subcommittees between World War I and 1958. The number of active subcommittees varied over the years. Most existed only for a few years, but some continued for over a decade. The subcommittees met three or four times per year, often at the laboratory most closely associated with the area of research. A team of laboratory researchers presented briefings on their recent activities and plans for the future. The Subcommittee on Combustion existed from 1945 to the NACA’s demise in 1958.

Index of NACA Technical Publications, 1949 - May, 1951

NASA Technical Reports Server (NTRS)

1952-01-01

The Preface to the Index of NACA Technical Publications, 1915-1949, mentioned that regular supplements would be issued in the future. This is the first such Supplement and covers those documents issued through May of 1951. Similar arrangement is used in both Indexes. First, there is a classified listing of the subject categories; second, a chronological listing of NACA publications under each subject category; third, an alphabetical index to the subject categories; and finally, an author index. The latter feature was not included in the basic 1915-1949 Index but has been issued separately and is available upon request. Immediately following this Preface is an Explanatory Chart of NACA Publications Series Designations which may be of use in identifying references to NACA documents encountered in the literature.

Flow Control Application on a Submerged Inlet Characterized by Three-Component LDV

DTIC Science & Technology

2010-12-01

boundary layer deficit accounted for less variation in stresses experienced by the compressor blades . These studies demonstrate the effect of geometry on... deficit region provided the best results. The airspeed and inlet velocity simulated takeoff and landing conditions; velocities ranged from Mach 0.1-0.3...uniformity of the total pressure profile at the compressor face prevents fatigue loading of the blades as they rotate.(5) Pressure recovery directly

A restored NACA P-51D Mustang in flight

NASA Image and Video Library

2000-09-15

The huge compass rose on Rogers Dry Lake formed a backdrop for a genuine NACA (National Advisory Committee for Aeronautics) P-51D Mustang owned and flown by William C. Allmon during a visit to the NASA Dryden Flight Research Center in California's Mojave Desert Sept. 15, 2000 for a reunion of former NACA employees. The NACA was the forerunner of NASA.

NACA Muroc Staff of 1949 at NACA barbecue

NASA Technical Reports Server (NTRS)

1949-01-01

On a nice day in November 1949 the NACA High-Speed Flight Station employees enjoy a break from a week of research by attending a barbecue on the Rawliegh Duntley ranch. The food was excellent and the camaraderie with friends and family members was welcome. Games were played with the winners applauded--fun for everyone before the start of another week.

Aeronautics in NACA and NASA

NASA Technical Reports Server (NTRS)

1991-01-01

Initiated in 1915, the National Advisory Committee for Aeronautics/National Aeronautics and Space Administration (NACA/NASA) aeronautical programs have been the keystone of a sustained U.S. Government, industry, and university research effort which has been a primary factor in the development of our remarkable air transportation systems, the country's largest positive trade balance component, and the world's finest military Air Force. This overview summarizes the flow of events, and the major trends, that have led from the NACA origins to the present NASA Aeronautics program, and indicates some important directions for the years ahead.

Groundbreaking Ceremony at the NACA's Plum Brook Station

NASA Image and Video Library

1956-09-21

Addison Rothrock, the National Advisory Committee for Aeronautics’s (NACA) Assistant Director of Research, speaks at the groundbreaking ceremony for the Lewis Flight Propulsion Laboratory’s new test reactor at Plum Brook Station. This dedication event was held almost exactly one year after the NACA announced that it would build its $4.5 million nuclear reactor on 500 acres of the army’s 9000-acre Plum Brook Ordnance Works. The site was located in Sandusky, Ohio, approximately 60 miles west of the NACA Lewis laboratory in Cleveland. Lewis Director Raymond Sharp is seated to the left of Rothrock, Congressman Albert Baumhart and NACA Secretary John Victory are to the right. Many government and local officials were on hand for the press conference and ensuing luncheon. In the wake of World War II the military, the Atomic Energy Commission, and the NACA became interested in the use of atomic energy for propulsion and power. A Nuclear Division was established at NACA Lewis in the early 1950s. The division’s request for a 60-megawatt research reactor was approved in 1955. The semi-remote Plum Brook location was selected over 17 other possible sites. Construction of the Plum Brook Reactor Facility lasted five years. By the time of its first trial runs in 1961 the aircraft nuclear propulsion program had been cancelled. The space age had arrived, however, and the reactor would be used to study materials for a nuclear powered rocket.

Blended Wing Body Systems Studies: Boundary Layer Ingestion Inlets With Active Flow Control

NASA Technical Reports Server (NTRS)

Geiselhart, Karl A. (Technical Monitor); Daggett, David L.; Kawai, Ron; Friedman, Doug

2003-01-01

A CFD analysis was performed on a Blended Wing Body (BWB) aircraft with advanced, turbofan engines analyzing various inlet configurations atop the aft end of the aircraft. The results are presented showing that the optimal design for best aircraft fuel efficiency would be a configuration with a partially buried engine, short offset diffuser using active flow control, and a D-shaped inlet duct that partially ingests the boundary layer air in flight. The CFD models showed that if active flow control technology can be satisfactorily developed, it might be able to control the inlet flow distortion to the engine fan face and reduce the powerplant performance losses to an acceptable level. The weight and surface area drag benefits of a partially submerged engine shows that it might offset the penalties of ingesting the low energy boundary layer air. The combined airplane performance of such a design might deliver approximately 5.5% better aircraft fuel efficiency over a conventionally designed, pod-mounted engine.

Re-Computation of Numerical Results Contained in NACA Report No. 496

NASA Technical Reports Server (NTRS)

Perry, Boyd, III

2015-01-01

An extensive examination of NACA Report No. 496 (NACA 496), "General Theory of Aerodynamic Instability and the Mechanism of Flutter," by Theodore Theodorsen, is described. The examination included checking equations and solution methods and re-computing interim quantities and all numerical examples in NACA 496. The checks revealed that NACA 496 contains computational shortcuts (time- and effort-saving devices for engineers of the time) and clever artifices (employed in its solution methods), but, unfortunately, also contains numerous tripping points (aspects of NACA 496 that have the potential to cause confusion) and some errors. The re-computations were performed employing the methods and procedures described in NACA 496, but using modern computational tools. With some exceptions, the magnitudes and trends of the original results were in fair-to-very-good agreement with the re-computed results. The exceptions included what are speculated to be computational errors in the original in some instances and transcription errors in the original in others. Independent flutter calculations were performed and, in all cases, including those where the original and re-computed results differed significantly, were in excellent agreement with the re-computed results. Appendix A contains NACA 496; Appendix B contains a Matlab(Reistered) program that performs the re-computation of results; Appendix C presents three alternate solution methods, with examples, for the two-degree-of-freedom solution method of NACA 496; Appendix D contains the three-degree-of-freedom solution method (outlined in NACA 496 but never implemented), with examples.

Preliminary Data on the Effects of Inlet Pressure Distortions on the J57-P-1 Turbojet Engine

NASA Technical Reports Server (NTRS)

Wallner, Lewis E.; Lubick, Robert J.; Einstein, Thomas H.

1954-01-01

An investigation to determine the steady-state and surge characteristics of the J57-P-1 two-spool turbojet engine with various inlet air-flow distortions was conducted in the altitude wind tunnel at the NACA Lewis laboratory. Along with a uniform inlet total-pressure distribution, one circumferential and three radial pressure distortions were investigated. Data were obtained over a complete range of compressor speeds both with and without intercompressor air bleed at a flight Mach number of 0.8 and at altitudes of 35,000 and 50,000 feet. Total-pressure distortions of the magnitudes investigated had very little effect on the steady-state operating line for either the outer or inner compressor. The small radial distortions investigated also had engine over that obtained with the uniform inlet pressure distribution. The circumferential distortion, however, raised the minimum speed at which the engine could operate without encountering surge when the intercompressor bleeds were closed. This increase in minimum speed resulted in a substantial reduction in the operable speed range accompanied by a reduction in the altitude operating limit.

Index of Naca Technical Publications, June 1953 - May 1954

NASA Technical Reports Server (NTRS)

1954-01-01

The Preface to the Index of NACA Technical Publications, 1915 - 1949, mentioned that regular supplements would be issued in the future. This is the third such Supplement and covers those documents issued from June 1953 through May 1954. Also included are certain documents dated prior to June 1953 which have been declassified during the period covered by this supplement. Similar arrangement is used in these Indexes. First, there is a classified listing of the subject categories; second, a chronological listing of NACA publications under each subject category; third, an alphabetical index to the subject categories; and finally, an author index. Immediately following this Preface is an Explanatory Chart of NACA Publications Series Designations which may be of use in identifying references to NACA research reports encountered in the literature.

NACA Photographer North American F-100A (NACA-200) Super Sabre Airplane take-off. The blowing-tupe

NASA Technical Reports Server (NTRS)

1957-01-01

NACA Photographer North American F-100A (NACA-200) Super Sabre Airplane take-off. The blowing-tupe boundary-layer control on the leading- and trailing-edge provided large reductions in takeoff and landing approach speeds. Approach speeds were reduced by about 10 knots (Mar 1960). Note: Used in publication in Flight Research at Ames; 57 Years of Development and Validation of Aeronautical Technology NASA SP-1998-3300 fig. 102 and and Memoirs of a Flight Test Engneer NASA SP-2002-4525

Pressure distribution over an NACA 23012 airfoil with an NACA 23012 external-airfoil flap

NASA Technical Reports Server (NTRS)

Wenzinger, Carl J

1938-01-01

Report presents the results of pressure-distribution tests of an NACA 23012 airfoil with an NACA 23012 external airfoil flap made in the 7 by 10-foot wind tunnel. The pressures were measured on the upper and lower surfaces at one chord section on both the main airfoil and on the flap for several different flap deflections and at several angles of attack. A test installation was used in which the airfoil was mounted horizontally in the wind tunnel between vertical end planes so that two-dimensional flow was approximated. The data are presented in the form of pressure-distribution diagrams and as graphs of calculated coefficients for the airfoil-and-flap combination and for the flap alone.

Entrance to the NACA's Flight Propulsion Research Laboratory

NASA Image and Video Library

1948-08-21

The sign near the entrance of the National Advisory Committee for Aeronautics (NACA) Flight Propulsion Research Laboratory. The name was changed several weeks later to the Lewis Flight Propulsion Laboratory in honor of the NACA’s former Director of Aeronautical Research, George W. Lewis. The research laboratory has had five different names since its inception in 1941. The Cleveland laboratory was originally known as the NACA Aircraft Engine Research Laboratory. In 1947 it was renamed the NACA Flight Propulsion Research Laboratory to reflect the expansion of the research activities beyond just engines. Following the death of George Lewis, the name was changed to the NACA Lewis Flight Propulsion Laboratory in September 1948. On October 1, 1958, the lab was incorporated into the new NASA space agency, and it was renamed the NASA Lewis Research Center. Following John Glenn’s flight on the space shuttle, the name was changed again to the NASA Glenn Research Center on March 1, 1999. From his office in Washington DC, George Lewis managed the aeronautical research conducted at the NACA for over 20 years. His most important accomplishment, however, may have been an investigative tour of German research facilities in the fall of 1936. The visit resulted in the broadening of the scope of the NACA’s research and the physical expansion that included the new engine laboratory in Cleveland.

Index of NACA Technical Publications: June, 1955 - June, 1956

NASA Technical Reports Server (NTRS)

1956-01-01

This Index of NACA Technical Publications covers those NACA research reports issued in the period of June 1955 through June 1956. It is the fifth supplement to the basic 1919-1949 Index. The res ear c h reports issued prior to June 1955 which have been declassified since that date have also been included. In addition, current announcement of newly declassified materials is regularly made in the NACA Research Abstracts and Reclassification Notice. The arrangement of the present Index follows that of its predecessors: (1) A listing of the subject categories by numerical classifications, (2) a chronological listing of the NACA research reports under each subject category, (3) an aIphabe ic a I index to the subject categories, and (4) an author index. An Explanatory Chart on page iii may be helpful in identifying references to NACA research reports encountered in the literature. Entries included herein duplicate in part the information of the index cards furnished with the individual research reports. Recipients maintaining card fiIes may wish to discard those index cards on hand for unclassified research reports issued during the June 1955-June 1956 period. Newly available research reports are currently announced in the NACA Research Abstracts and Reclassification Notice and are normally available for a period of five years after announcement. Most of the older research reports (those issued prior to May 1951) are thus available on a "loan only" basis within the United States

Spatial and mineralogic variation of Na-Ca alteration in Laramide porphyry systems of Arizona

NASA Astrophysics Data System (ADS)

Runyon, S.; Seedorff, E.; Barton, M. D.; Mazdab, F. K.; Lecumberri-Sanchez, P.; Steele-MacInnis, M.

2017-12-01

Na-Ca alteration is characterized by the metasomatic addition of Ca ± Na and the loss of K. Minor volumes of Na-Ca alteration in Laramide porphyry systems develops from 3 to 8 km paleodepth. Mineral assemblages, mineral compositions, hydrogen isotopes, whole-rock analyses, and reconnaissance fluid inclusion characteristics have been documented for Na-Ca alteration in Laramide porphyry systems such as Tea Cup and Sierrita. Volumetrically minor Na-Ca alteration in Laramide porphyry systems documented in this study commonly takes the form of one of three mineral assemblages: albite-epidote-chlorite, Na-plagioclase-actinolite ± epidote, and garnet- or diopside-stable Na-plagioclase-actinolite ± epidote. These different Na-Ca mineral assemblages have broad spatial relationships, from shallow albite-chlorite-epidote to deeper Na-plagioclase-actinolite within a given district. Hydrogen isotope data on Na-Ca alteration minerals shows consistently distinct δD compositions of Na-Ca alteration minerals compared to igneous minerals in a given district. Further, calculated hydrogen isotope composition of fluids in equilibrium with Na-Ca alteration minerals are consistently enriched in δD compared to magmatic-hydrothermal fluids. Whole-rock analyses show consistent losses of K and variable addition of Na and Ca across different Na-Ca alteration assemblages. Na-Ca alteration has been well documented associated with the Jurassic arc. Previous studies demonstrated through mass balance, timing and spatial relationships, isotopic, and fluid inclusion studies that Na-Ca alteration associated with the Jurassic arc likely formed from the circulation of external, highly saline, non-magmatic fluids (e.g., Battles and Barton, 1995; Dilles et al., 1995). Na-Ca alteration documented in Laramide systems is generally similar to Na-Ca alteration documented along the Jurassic arc in mineral assemblages, compositions, and timing, but the volume of Na-Ca alteration in the Laramide systems is

A restored NACA P-51D Mustang in flight

NASA Image and Video Library

2000-09-15

Bill Allmon of Las Vegas, Nevada, brought his restored NACA P-51D to a reunion of former NACA employees at the NASA Dryden Flight Research Center located at Edwards Air Force Base, Calif., on Sept. 15, 2000. Allmon's award-winning restoration is a genuine former NACA testbed that saw service at the Langley Research Center in Virginia in the late 1940s. Later this Mustang was put on outdoor static display as an Air National Guard monument in Pittsburgh, Pa., where exposure to the elements ravaged its metal structure, necessitating an extensive four-year rebuild.

NACA Engineer Examines Wind Tunnel Compressor Blades

NASA Image and Video Library

1955-09-21

An engineer examines the main compressor for the 10- by 10-Foot Supersonic Wind Tunnel at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The engineers were preparing the new wind tunnel for its initial runs in early 1956. The 10- by 10 was the most powerful propulsion wind tunnel in the nation. The facility was part of Congress’ Unitary Plan Act which coordinated wind tunnel construction at the NACA, Air Force, industry, and universities. The 10- by 10 was the largest of the three NACA tunnels built under the act. The 20-foot diameter eight-stage axial flow compressor, seen in this photograph, could generate air flows up to Mach 2.5 through the test section. The stainless steel compressor had 584 blades ranging from 1.8 to 3.25 feet in length. This main compressor was complemented by a secondary axial flow compressor. Working in tandem the two could generate wind streams up to Mach 3.5. The Cleveland Chamber of Commerce presented NACA Lewis photographer Bill Bowles with a second place award for this photograph in their Business and Professional category. The photograph was published in October 1955 edition of its periodical, The Clevelander, which highlighted local professional photographers. Fellow Lewis photographer Gene Giczy won second place in another category for a photograph of Cleveland Municipal Airport.

Index of NACA Technical Publications, July 1956 - June 1957

NASA Technical Reports Server (NTRS)

1957-01-01

This index of NACA Technical Publications covers the NACA research reports issued in the period of July 1956 through June 1957. It is the sixth supplement to the basic 1915-1949 Index. The research reports issued prior to July 1956 which have been declassified since that date have also been included. A list of these reports may be found on pages 243-244. Cards for this list may be discarded as entries for them are included in this Index. Current announcement of newly declassified materials is regularly made in the NACA Research Abstracts and Reclassification Notice. The arrangement of this Index follows: (1) Explanatory chart of NACA publications series designations, (2) outline of subject classification system, (3) chronological list of NACA reports under each subject classification, (4) list of reports declassified from July 1956 through June 1957, (5) alphabetical index to subject categories, and (6) author index. Entries included herein duplicate in part the information of the index cards furnished with the individual research reports. Recipients maintaining card files may wish to discard those index cards on hand for unclassified research reports issued during the July 1956-June 1957 period. Such cards were printed on yellow stock for easy identification in the discard process. Please note that some classified reports issued during the July-December 1956 period are included in the yellow stock area. Therefore care must be taken to avoid destroying such cards. Newly available research reports are currently announced in the NACA Research Abstracts and Reclassification Notice and are normally available for a period of five years after announcement. Most of the older research reports (those issued prior to July 1952) are thus available on a "loan only" basis within the United states.

NACA Pilots at the Aircraft Engine Research Laboratory

NASA Image and Video Library

1945-07-21

The Aircraft Engine Research Laboratory’s pilot corps during the final days of World War II: from left to right, Joseph Vensel, Howard Lilly, William Swann, and Joseph Walker. William “Eb” Gough joined the group months after this photograph. These men were responsible for flying the various National Advisory Committee for Aeronautics (NACA) aircraft to test new engine modifications, study ice buildup, and determine fuel performance. Vensel, a veteran pilot from Langley, was the Chief of Flight Operations and a voice of reason at the laboratory. In April 1947 Vensel was transferred to lead the new Muroc Flight Tests Unit in California until 1966. Lilly was a young pilot with recent Navy experience. Lilly also flew in the 1946 National Air Races. He followed Vensel to Muroc in July 1947 where he became the first NACA pilot to penetrate the sound barrier. On May 3, 1948, Lilly became the first NACA pilot to die in the line of duty. Swann was a young civilian pilot when he joined the NACA. He spent his entire career at the Cleveland laboratory, and led the flight operations group from the early 1960s until 1979. Two World War II veterans joined the crew after the war. Walker was a 24-year-old P–38 reconnaissance pilot. He joined the NACA as a physicist in early 1945 but soon worked his way into the cadre of pilots. Walker later gained fame as an X-plane pilot at Muroc and was killed in a June 1966 fatal crash. Gough survived being shot down twice during the war and was decorated for flying rescue missions in occupied areas.

Aerodynamic Characteristics of a Two-blade NACA 10-(3)(062)-045 Propeller and of a Two-blade NACA 10-(3)(08)-045 Propeller

NASA Technical Reports Server (NTRS)

Solomon, William

1953-01-01

Characteristics are given for the two-blade NACA 10-(3)(062)-045 propeller and for the two-blade NACA 10-(3)(08)-045 propeller over a range of advance ratio from 0.5 to 3.8, through a blade-angle range from 20 degrees to 55 degrees measured at the 0.75 radius. Maximum efficiencies of the order of 91.5 to 92 percent were obtained for the propellers. The propeller with the thinner airfoil sections over the outboard portion of the blades, the NACA 10-(3)(062)-045 propeller, had lower losses at high tip speeds, the difference amounting to about 5 percent at a helical tip Mach number of 1.10.

Some NACA Muroc personnel with snowman

NASA Technical Reports Server (NTRS)

1949-01-01

The late 1940s saw increased flight activity, and more women computers were needed at the NACA Muroc Flight Test Unit than the ones who had originally arrived in 1946. A call went out to the NACA Langley, Lewis, and Ames laboratories for more women computers. Pictured in this photograph with the Snowman are some of the women computers who responded to the call for help in 1948 along with Roxanah, Emily, Dorothy, who were already here. Standing left to right: Mary (Tut) Hedgepeth, from Langley; Lilly Ann Bajus, Lewis; Roxanah Yancey, Emily Stephens, Jane Collons (Procurement), Leona Corbett (Personnel), Angel Dunn, Langley. Kneeling left to right: Dorothy (Dottie) Crawford Roth, Lewis; Dorothy Clift Hughes, and Gertrude (Trudy) Wilken Valentine, Lewis. In National Advisory Committee for Aeronautics (NACA) terminology of 1946, computers were employees who performed laborious and time-consuming mathematical calculations and data reduction from long strips of records generated by onboard aircraft instrumentation. Virtually without exception, computers were female; at least part of the rationale seems to have been the notion that the work was long and tedious, and men were not thought to have the patience to do it. Though equipment changed over the years and most computers eventually found themselves programming and operating electronic computers, as well as doing other data processing tasks, being a computer initially meant long hours with a slide rule, hunched over illuminated light boxes measuring line traces from grainy and obscure strips of oscillograph film. Computers suffered terrible eyestrain, and those who didn't begin by wearing glasses did so after a few years. But they were initially essential employees at the Muroc Flight Test Unit and NACA High-Speed Flight Research Station, taking the oscillograph flight records and 'reducing' the data on them to make them useful to research engineers, who analyzed the data.

Analysis of the Na+/Ca2+ Exchanger Gene Family within the Phylum Nematoda

PubMed Central

He, Chao; O'Halloran, Damien M.

2014-01-01

Na+/Ca2+ exchangers are low affinity, high capacity transporters that rapidly transport calcium at the plasma membrane, mitochondrion, endoplasmic (and sarcoplasmic) reticulum, and the nucleus. Na+/Ca2+ exchangers are widely expressed in diverse cell types where they contribute homeostatic balance to calcium levels. In animals, Na+/Ca2+ exchangers are divided into three groups based upon stoichiometry: Na+/Ca2+ exchangers (NCX), Na+/Ca2+/K+ exchangers (NCKX), and Ca2+/Cation exchangers (CCX). In mammals there are three NCX genes, five NCKX genes and one CCX (NCLX) gene. The genome of the nematode Caenorhabditis elegans contains ten Na+/Ca2+ exchanger genes: three NCX; five CCX; and two NCKX genes. Here we set out to characterize structural and taxonomic specializations within the family of Na+/Ca2+ exchangers across the phylum Nematoda. In this analysis we identify Na+/Ca2+ exchanger genes from twelve species of nematodes and reconstruct their phylogenetic and evolutionary relationships. The most notable feature of the resulting phylogenies was the heterogeneous evolution observed within exchanger subtypes. Specifically, in the case of the CCX exchangers we did not detect members of this class in three Clade III nematodes. Within the Caenorhabditis and Pristionchus lineages we identify between three and five CCX representatives, whereas in other Clade V and also Clade IV nematode taxa we only observed a single CCX gene in each species, and in the Clade III nematode taxa that we sampled we identify NCX and NCKX encoding genes but no evidence of CCX representatives using our mining approach. We also provided re-annotation for predicted CCX gene structures from Heterorhabditis bacteriophora and Caenorhabditis japonica by RT-PCR and sequencing. Together, these findings reveal a complex picture of Na+/Ca2+ transporters in nematodes that suggest an incongruent evolutionary history of proteins that provide central control of calcium dynamics. PMID:25397810

Na/Ca Ratio in Large Benthic Foraminifera as a Novel Proxy for Past Ocean Calcium

NASA Astrophysics Data System (ADS)

Rosenthal, Y.; Hauzer, H.; Evans, D.; Erez, J.

2017-12-01

Culture experiments with Operculina ammonoides (a large symbiont bearing benthic foraminifer and an extant relative of the Eocene Nummulites) were carried out varying seawater [Ca], temperature and salinity. The main results of these experiments are: 1. Na/Ca in these foraminifera shells varies with the Na/Ca ratio in the seawater 2. Na/Ca shows small, non-systematic variations with temperature (22-28 ºC) that are within our analytical precision. 3. Na/Ca in the shells show very low changes, increasing linearly with salinity. The sensitivity to salinity is very low compared to that caused by changes of Na/Ca in seawater. Over the seawater experimental range of Na/Ca (10-18 mM), a change of 5 ppt salinity induced a slight Na/Ca increase comparable to the analytical error for Na, or that caused by temperature. Initial reconstructions of seawater [Ca], based on these calibrations, generally agree well with previous models and reconstructions confirming that seawater [Ca] concentrations were substantially higher during the early-mid Cenozoic than today.

NACA Conference on Aircraft Loads, Flutter, and Structures: A compilation of Papers Presented.

DTIC Science & Technology

1953-03-04

Variation of Atmospheric Turbulence With Altitude and Its Effect on Airplane Gust Loads . . . by Robert L. McDougal, Thomas L. Coleman, and Philip L. Smith ...SKOPINSKI, T. H. NACA - Langley Laboratory xvii CONFIDENTIAL CONFIDENTIAL SMETHERS, Rollo G. Bureau of Aeronautics SMITH , Dana W. NACA Subcommittee on...Aircraft Structural Materials SMITH , Frank C. National Bureau of Standards SMITH , Henry G. Hughes Aircraft Co. SMITH , Howard W. NACA Subcommittee on Aircraft

Review of parameters influencing the structural response of a submerged body under cavitation conditions

NASA Astrophysics Data System (ADS)

Escaler, X.; De La Torre, O.; Farhat, M.

2015-12-01

Submerged structures that operate under extreme flows are prone to suffer large scale cavitation attached to their surfaces. Under such conditions the added mass effects differ from the expected ones in pure liquids. Moreover, the existence of small gaps between the structure and surrounding bodies filled with fluid also influence the dynamic response. A series of experiments and numerical simulations have been carried out with a truncated NACA0009 hydrofoil mounted as a cantilever beam at the LMH-EPFL cavitation tunnel. The three first modes of vibration have been determined and analysed under various hydrodynamic conditions ranging from air and still water to partial cavitation and supercavitation. A remote nonintrusive excitation system with piezoelectric patches has been used for the experiments. The effects of the cavity properties and the lateral gap size on the natural frequencies and mode shapes have been determined. As a result, the significance of several parameters in the design of such structures is discussed.

D-558-1 on ramp with ground crew and NACA pilot Bob Champine

NASA Technical Reports Server (NTRS)

1949-01-01

NACA test pilot Robert Champine is seen in the cockpit of the Douglas D-558-1 Skystreak with the ground crew. Robert A. Champine was a research pilot with the National Advisory Committee for Aeronautics (NACA) and the National Aeronautics and Space Administration (NASA) from December 1947 to 1979, when he retired as Langley Research Center's senior research pilot. He began his career with the NACA at the Langley Memorial Aeronautical Laboratory in Hampton, Virginia (as Langley Research Center was then called). He transferred to the NACA's High-Speed Flight Research Station in the Mojave Desert of California in October 1948, where he flew the X-1 and D-558-1 and -2 research airplanes. On December 2, 1948, Bob became the 6th man and 3rd civilian to break the mysterious sound barrier. He exceeded Mach 1 on NACA flight 23 checking handling qualities and pressure distribution on the XS-1 #2, after having been dropped from the B-29 mother ship, above the Rogers Dry Lake in California. On August 4, 1949, NACA flight 32, he again exceeded Mach 1 performing rolls, pullups, sideslips, and check of stabilizer effectiveness. This was his 13th and last flight in the XS-1. He flew the first NACA research flight of the D-558-1 #3 (Skystreak) on April 22, 1949, and the first NACA research flight of the D-558-2 #2 (Skyrocket) on May 24, 1949, beginning the supersonic research program for these aircraft on June l, 1949. Conceived in 1945, the D558-1 Skystreak was designed by the Douglas Aircraft Company for the U.S. Navy Bureau of Aeronautics, in conjunction with the National Advisory Committee for Aeronautics (NACA). The Skystreaks were turojet powered aircraft that took off from the ground under their own power and had straight wings and tails. All three D-558-1 Skystreaks were powered by Allison J35-A-11 turbojet engines producing 5,000 pounds of thrust. All the Skystreaks were initially painted scarlet, which lead to the nickname 'crimson test tube.' NACA later had the color of

Comparison of NACA 6-series and 4-digit airfoils for Darrieus wind turbines

NASA Astrophysics Data System (ADS)

Migliore, P. G.

1983-08-01

The aerodynamic efficiency of Darrieus wind turbines as effected by blade airfoil geometry was investigated. Analysis was limited to curved-bladed machines having rotor solidities of 7-21 percent and operating at a Reynolds number of 3 x 10 to the 6th. Ten different airfoils, having thickness-to-chord ratios of 12, 15, and 18 percent, were studied. Performance estimates were made using a blade element/momentum theory approach. Results indicated that NACA 6-series airfoils yield peak power coefficients as great as NACA 4-digit airfoils and have broader and flatter power coefficient-tip speed ratio curves. Sample calculations for an NACA 63(2)-015 airfoil showed an annual energy output increase of 17-27 percent, depending on rotor solidity, compared to an NACA 0015 airfoil.

NACA Conference on Aircraft Loads, Structures, and Flutter

NASA Technical Reports Server (NTRS)

1957-01-01

This document contains reproductions of technical papers on some of the most recent research results on aircraft loads, flutter, and structures from the NACA laboratories. These papers were presented by members of the staff of the NACA laboratories at the Conference held at the Langley Aeronautical Laboratory March 5, 6, and 7, 1957. The primary purpose of this Conference was to convey to contractors of the military services and others concerned with the design of aircraft these recent research results and to provide those attending an opportunity to discuss the results. The papers in this document are in the same form in which they were presented at the Conference in order to facilitate their prompt distribution. The original presentation and this record are considered as complementary to, rather than as substitutes for, the Committee?s more complete and formal reports. Accordingly, if information from this document is utilized it is requested that this document not be listed as a reference. Individual reports dealing with most of the information presented at the Conference will subsequently be published by NACA and will therefore be suitable as reference material.

Inlet Geomorphology Evolution

DTIC Science & Technology

2015-04-01

APR 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Inlet Geomorphology Evolution 5a. CONTRACT NUMBER 5b...Std Z39-18 Coastal Inlets Research Program Inlet Geomorphology Evolution The Inlet Geomorphology Evolution work unit of the CIRP evaluates

Historical perspectives on thermostructural research at the NACA Langley Aeronautical Laboratory from 1948 to 1958

NASA Technical Reports Server (NTRS)

Heldenfels, R. R.

1982-01-01

Some of the early research on structural problems produced by aerodynamic heating, conducted at the Langley Aeronautical Laboratory of the National Advisory Committee for Aeronautics from 1948 to 1958 is described. That was the last decade of the NACA; in 1958 NACA became the nucleus of NASA. The NACA initially contracted for research but was aware that a well-equipped and suitably staffed laboratory was required to fulfill its obligations. Langley was established in 1920; the other listed were added during the NACA expansion in the World War II years. Some specific research activities are described, starting with calculation of the temperature of the structure.

Historical perspectives on thermostructural research at the NACA Langley Aeronautical Laboratory from 1948 to 1958

NASA Astrophysics Data System (ADS)

Heldenfels, R. R.

Some of the early research on structural problems produced by aerodynamic heating, conducted at the Langley Aeronautical Laboratory of the National Advisory Committee for Aeronautics from 1948 to 1958 is described. That was the last decade of the NACA; in 1958 NACA became the nucleus of NASA. The NACA initially contracted for research but was aware that a well-equipped and suitably staffed laboratory was required to fulfill its obligations. Langley was established in 1920; the other listed were added during the NACA expansion in the World War II years. Some specific research activities are described, starting with calculation of the temperature of the structure.

Submerged in darkness: adaptations to prolonged submergence by woody species of the Amazonian floodplains

PubMed Central

Parolin, Pia

2009-01-01

Background In Amazonian floodplain forests, >1000 tree species grow in an environment subject to extended annual submergence which can last up to 9 months each year. Water depth can reach 10 m, fully submerging young and also adult trees, most of which reproduce during the flood season. Complete submergence occurs regularly at the seedling or sapling stage for many species that colonize low-lying positions in the flooding gradient. Here hypoxic conditions prevail close to the water surface in moving water, while anaerobic conditions are common in stagnant pools. Light intensities in the floodwater are very low. Questions and Aims Despite a lack of both oxygen and light imposed by submergence for several months, most leafed seedlings survive. Furthermore, underwater growth has also been observed in several species in the field and under experimental conditions. The present article assesses how these remarkable plants react to submergence and discusses physiological mechanisms and anatomical adaptations that may explain their success. PMID:19001429

NACA: 25 Years of Flight Research

NASA Image and Video Library

2018-05-10

A narrated film documentary of flight tests at the NACA and NASA’s Flight Research Center shows the X-1, D-558-II, X-3, X-4, X-5, and X-15 in flight and on the ground. The story describes what each aircraft contributed to flight’s expansion.

A preliminary investigation of the drag and ventilation characteristics of livestock haulers

NASA Technical Reports Server (NTRS)

Hoffman, J. A.; Sandin, D. R.

1983-01-01

A wind tunnel evaluation of the drag and ventilation characteristics of a conventional (unmodified) and five modified subscale model livestock haulers at 0 deg yaw angle has been made. The unmodified livestock hauler has a relatively high drag coefficient, and a low velocity recirculation region exists in the forward portion of the hauler. The use of a streamlined forebody and enclosed gap reduced the drag coefficient of one model by 42% and improved the rate at which contaminants can be flushed from the cargo compartment by a factor of 2.5. From the limited data obtained, any increase in the fraction of open area of the trailer sides was found to improve the trailer ventilation. The use of a ram air inlet can improve the ventilation within the hauler and remove the low velocity recirculation region at the expense of a modest increase in the truck's drag coefficient. A mathematical model for vehicles with ram air or NACA submerged inlets was developed and appears to adequately predict the ventilation characteristics of livestock haulers.

Aerodynamic data banks for Clark-Y, NACA 4-digit and NACA 16-series airfoil families

NASA Technical Reports Server (NTRS)

Korkan, K. D.; Camba, J., III; Morris, P. M.

1986-01-01

With the renewed interest in propellers as means of obtaining thrust and fuel efficiency in addition to the increased utilization of the computer, a significant amount of progress was made in the development of theoretical models to predict the performance of propeller systems. Inherent in the majority of the theoretical performance models to date is the need for airfoil data banks which provide lift, drag, and moment coefficient values as a function of Mach number, angle-of-attack, maximum thickness to chord ratio, and Reynolds number. Realizing the need for such data, a study was initiated to provide airfoil data banks for three commonly used airfoil families in propeller design and analysis. The families chosen consisted of the Clark-Y, NACA 16 series, and NACA 4 digit series airfoils. The various component of each computer code, the source of the data used to create the airfoil data bank, the limitations of each data bank, program listing, and a sample case with its associated input-output are described. Each airfoil data bank computer code was written to be used on the Amdahl Computer system, which is IBM compatible and uses Fortran.

Rocket Propellant Talk at the 1957 NACA Lewis Inspection

NASA Image and Video Library

1957-10-21

A researcher works a demonstration board in the Rocket Engine Test Facility during the 1957 Inspection of the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory in Cleveland, Ohio. Representatives from the military, aeronautical industry, universities, and the press were invited to the laboratory to be briefed on the NACA’s latest research efforts and tour the test facilities. Over 1700 people visited the Lewis during the October 7-10, 1957 Inspection. The Soviet Union launched their first Sputnik satellite just days before on October 4. NACA Lewis had been involved in small rockets and propellants research since 1945, but the NACA leadership was wary of involving itself too deeply with the work since ballistics traditionally fell under the military’s purview. The Lewis research was performed by the High Temperature Combustion section in the Fuels and Lubricants Division in a series of small cinderblock test cells. The rocket group was expanded in 1952 and made several test runs in late 1954 using liquid hydrogen as a propellant. A larger test facility, the Rocket Engine Test Facility, was approved and became operational just in time for the Inspection.

Low-speed performance of an axisymmetric, mixed-compression, supersonic inlet with auxiliary inlets

NASA Technical Reports Server (NTRS)

Trefny, C. J.; Wasserbauer, J. W.

1986-01-01

A test program was conducted to determine the aerodynamic performance and acoustic characteristics associated with the low-speed operation of a supersonic, axisymmetric, mixed-compression inlet with auxiliary inlets. Blow-in-auxiliary doors were installed on the NASA Ames P inlet. One door per quadrant was located on the cowl in the subsonic diffuser selection of the inlet. Auxiliary inlets with areas of 20 and 40 percent of the inlet capture area were tested statically and at free-stream Mach numbers of 0.1 and 0.2. The effects of boundary layer bleed inflow were investigated. A JT8D fan simulator driven by compressed air was used to pump inlet flow and to provide a characteristic noise signature. Baseline data were obtained at static free-stream conditions with the sharp P-inlet cowl lip replaced by a blunt lip. Auxiliary inlets increased overall total pressure recovery of the order of 10 percent.

Investigation of the NACA 4-(5)(08)-03 and NACA 4-(10)(08)-03 Two-Blade Propellers at Forward Mach Numbers to 0.725 to Determine the Effects of Camber and Compressibility on Performance

NASA Technical Reports Server (NTRS)

Delano, James B

1951-01-01

As part of a general investigation of propellers at high forward speeds, tests of two-blade propellers having the NACA 4-(5)(08)-03 and NACA 4-(10)(08)-03 blade designs were made in the Langley 8-foot high-speed tunnel through a range of blade angle from 20 degrees to 60 degrees for forward Mach numbers from 0.165 to 0.70 to determine the effect of camber and compressibility on propeller characteristics. Results previously reported for similar tests of a two-blade propeller having the NACA 4-(3)(08)-03 blade design are included for comparison.

Ramjet Testing in the NACA's Altitude Wind Tunnel

NASA Image and Video Library

1946-02-21

A 20-inch diameter ramjet installed in the Altitude Wind Tunnel at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The Altitude Wind Tunnel was used in the 1940s to study early ramjet configurations. Ramjets provide a very simple source of propulsion. They are basically a tube which takes in high-velocity air, ignites it, and then expels the expanded airflow at a significantly higher velocity for thrust. Ramjets are extremely efficient and powerful but can only operate at high speeds. Therefore a turbojet or rocket was needed to launch the vehicle. This NACA-designed 20-inch diameter ramjet was installed in the Altitude Wind Tunnel in May 1945. The ramjet was mounted under a section of wing in the 20-foot diameter test section with conditioned airflow ducted directly to the engine. The mechanic in this photograph was installing instrumentation devices that led to the control room. NACA researchers investigated the ramjet’s overall performance at simulated altitudes up to 47,000 feet. Thrust measurements from these runs were studied in conjunction with drag data obtained during small-scale studies in the laboratory’s small supersonic tunnels. An afterburner was attached to the ramjet during the portions of the test program. The researchers found that an increase in altitude caused a reduction in the engine’s horsepower. They also determined the optimal configurations for the flameholders, which provided the engine’s ignition source.

An experimental low Reynolds number comparison of a Wortmann FX67-K170 airfoil, a NACA 0012 airfoil and a NACA 64-210 airfoil in simulated heavy rain

NASA Technical Reports Server (NTRS)

Craig, Anthony P.; Hansman, R. John

1987-01-01

Wind tunnel experiments were conducted on Wortmann FX67-K170, NACA 0012, and NACA 64-210 airfoils at rain rates of 1000 mm/hr and Reynolds numbers of 310,000 to compare the aerodynamic performance degradation of the airfoils and to attempt to identify the various mechanisms which affect performance in heavy rain conditions. Lift and drag were measured in dry and wet conditions, a variety of flow visualization techniques were employed, and a computational code which predicted airfoil boundary layer behavior was used. At low angles of attack, the lift degradation in wet conditions varied significantly between the airfoils. The Wortmann section had the greatest overall lift degradation and the NACA 64-210 airfoil had the smallest. At high angles of attack, the NACA 64-210 and 0012 airfoils had improved aerodynamic performance in rain conditions due to an apparent reduction of the boundry layer separation. Performance degradation in heavy rain for all three airfoils at low angles of attack could be emulated by forced boundary layer transition near the leading edge. The secondary effect occurs at time scales consistent with top surface water runback times. The runback layer is thought to effectively alter the airfoil geometry. The severity of the performance degradation for the airfoils varied. The relative differences appeared to be related to the susceptibility of each airfoil to premature boundary layer transition.

46 CFR 7.35 - Sandy Hook, NJ to Cape May, NJ.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Breakwater Light “2” to Shark River Inlet South Breakwater Light “1”. (b) A line drawn from Manasquan Inlet North Breakwater Light to Manasquan Inlet South Breakwater Light. (c) A line drawn along the submerged... Light “5”; thence along the submerged Barnegat Inlet South Breakwater to shore. (d) A line drawn from...

46 CFR 7.35 - Sandy Hook, NJ to Cape May, NJ.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Breakwater Light “2” to Shark River Inlet South Breakwater Light “1”. (b) A line drawn from Manasquan Inlet North Breakwater Light to Manasquan Inlet South Breakwater Light. (c) A line drawn along the submerged... Light “5”; thence along the submerged Barnegat Inlet South Breakwater to shore. (d) A line drawn from...

46 CFR 7.35 - Sandy Hook, NJ to Cape May, NJ.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Breakwater Light “2” to Shark River Inlet South Breakwater Light “1”. (b) A line drawn from Manasquan Inlet North Breakwater Light to Manasquan Inlet South Breakwater Light. (c) A line drawn along the submerged... Light “5”; thence along the submerged Barnegat Inlet South Breakwater to shore. (d) A line drawn from...

46 CFR 7.35 - Sandy Hook, NJ to Cape May, NJ.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Breakwater Light “2” to Shark River Inlet South Breakwater Light “1”. (b) A line drawn from Manasquan Inlet North Breakwater Light to Manasquan Inlet South Breakwater Light. (c) A line drawn along the submerged... Light “5”; thence along the submerged Barnegat Inlet South Breakwater to shore. (d) A line drawn from...

Role of Na+/Ca2+ Exchangers in Therapy Resistance of Medulloblastoma Cells.

PubMed

Pelzl, Lisann; Hosseinzadeh, Zohreh; Al-Maghout, Tamer; Singh, Yogesh; Sahu, Itishri; Bissinger, Rosi; Schmidt, Sebastian; Alkahtani, Saad; Stournaras, Christos; Toulany, Mahmoud; Lang, Florian

2017-01-01

Alterations of cytosolic Ca2+-activity ([Ca2+]i) are decisive in the regulation of tumor cell proliferation, migration and survival. Transport processes participating in the regulation of [Ca2+]i include Ca2+ extrusion through K+-independent (NCX) and/or K+-dependent (NCKX) Na+/Ca2+-exchangers. The present study thus explored whether medulloblastoma cells express Na+/Ca2+-exchangers, whether expression differs between therapy sensitive D283 and therapy resistant UW228-3 medulloblastoma cells, and whether Na+/Ca2+-exchangers participate in the regulation of cell survival. In therapy sensitive D283 and therapy resistant UW228-3 medulloblastoma cells transcript levels were estimated by RT-PCR, protein abundance by Western blotting, cytosolic Ca2+-activity ([Ca2+]i) from Fura-2-fluorescence, Na+/ Ca2+-exchanger activity from the increase of [Ca2+]i (Δ[Ca2+]i) and from whole cell current (Ica) following abrupt replacement of Na+ containing (130 mM) and Ca2+ free by Na+ free and Ca2+ containing (2 mM) extracellular perfusate as well as cell death from PI -staining and annexin-V binding in flow cytometry. The transcript levels of NCX3, NCKX2, and NCKX5, protein abundance of NCX3, slope and peak of Δ[Ca2+]i as well as Ica were significantly lower in therapy sensitive D283 than in therapy resistant UW228-3 medulloblastoma cells. The Na+/Ca2+-exchanger inhibitor KB-R7943 (10 µM) significantly blunted Δ[Ca2+]i, and augmented the ionizing radiation-induced apoptosis but did not significantly modify clonogenicity of medulloblastoma cells. Apoptosis was further enhanced by NCX3 silencing. Na+/Ca2+-exchanger activity significantly counteracts apoptosis but does not significantly affect clonogenicity after radiation of medulloblastoma cells. © 2017 The Author(s). Published by S. Karger AG, Basel.

Acoustic and adsorption properties of submerged wood

NASA Astrophysics Data System (ADS)

Hilde, Calvin Patrick

Wood is a common material for the manufacture of many products. Submerged wood, in particular, is used in niche markets, such as the creation of musical instruments. An initial study performed on submerged wood from Ootsa Lake, British Columbia, provided results that showed that the wood was not suitable for musical instruments. This thesis re-examined the submerged wood samples. After allowing the wood to age unabated in a laboratory setting, the wood was retested under the hypothesis that the physical acoustic characteristics would improve. It was shown, however, that the acoustic properties became less adequate after being left to sit. The adsorption properties of the submerged wood were examined to show that the submerged wood had a larger accessible area of wood than that of control wood samples. This implied a lower amount of crystalline area within the submerged wood. From the combined adsorption and acoustic data for the submerged wood, relationships between the moisture content and speed of sound were created and combined with previous research to create a proposed model to describe how the speed of sound varies with temperature, moisture content and the moisture content corresponding to complete hydration of sorption sites within the wood.

Effect of inlet disturbances on fan inlet noise during a static test

NASA Technical Reports Server (NTRS)

Bekofske, K. L.; Sheer, R. E., Jr.; Wang, J. C. F.

1977-01-01

Measurements of fan rotor inlet noise taken during static test situations are at variance with aircraft engine flight data. In particular, static tests generally yield a significantly higher tone at blade passage frequency than that measured during flight. To explain this discrepancy, the extent of the influence of inlet ground vortices and large-scale inlet turbulence on the forward-radiated fan noise measured at a static test facility was investigated. While such inlet disturbances were generated intentionally in an anechoic test chamber, far-field acoustic measurements and inlet flow-field hot-film mappings of a fan rotor were obtained. Experimental results indicate that the acoustic effect of such disturbances appears to be less severe for supersonic than for subsonic tip speeds. Further, a reverse flow that occurs on the exterior cowl in static test facilities appears to be an additional prime candidate for creating inlet disturbances and causing variance between flight and static acoustic data.

New Ebb-Tidal Delta at an Old Inlet, Shark River Inlet, New Jersey

DTIC Science & Technology

2011-01-01

examine interacting beach and inlet processes and to test numerical simulation models for predicting morphology change at inlets. This study was...intertidal, oyster-encrusted Figure 4. A) Shark River Inlet, February-March 1920, post early construction (1915), but during rehabilitation of...the original State-built, curved jetties; B) Shark River Inlet, 23 January 1933, post construction of curved jetties and land reclamation of the flood

Subsonic Scarf Inlets Investigated

NASA Technical Reports Server (NTRS)

Abbott, John M.

2005-01-01

A computational investigation is underway at the NASA Glenn Research Center to determine the aerodynamic performance of subsonic scarf inlets. These inlets are characterized as being longer over the lower portion of the inlet, as shown in the preceding figure. One of the key variables being investigated in the research is the circumferential extent of the longer portion of the inlet. It shows two specific geometries that are being examined: one in which the length of the inlet transitions from long-to-short over the full 180 deg. from bottom to top, and a second in which the length transitions over 67.5 deg.

NACA Researcher Sets up a Test of a New Seat Design

NASA Image and Video Library

1954-05-21

A researcher at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory prepares for a test of an NACA-designed aircraft seat. The laboratory had undertaken a multi-year investigation into the causes and prevention of fires on low altitude aircraft crashes. The program was expanded in the mid-1950s to include the study of impact on passengers, types of seat restraints, and seat design. The crash impact portion of the program began by purposely wrecking surplus Fairchild C-82 Packet and Piper Cub aircraft into barricades at the end of a test runway at the Ravenna Arsenal, located approximately 40 miles south of the Lewis lab in Cleveland. Instrumented dummies and cameras were installed in the pilot and passenger areas. After determining the different loads and their effects on the passengers, the NACA researchers began designing new types of seats and restraints. The result was an elastic seat that flexed upon impact, absorbing 75 percent of the loads before it slowly recoiled. This photograph shows the seats mounted on a pendulum with a large spring behind the platform to provide the jolt that mimicked the forces of a crash. The seat was constructed without any potentially damaging metal parts and included rubber-like material, an inflated back and arms, and a seat cushion. After the pendulum tests, the researchers compared the flexible seats to the rigid seats during a crash of a transport aircraft. They found the passengers in the rigid seats received 66 percent higher g-forces than the NACA-designed seats.

Index of NACA Technical Publications: 1915-1949

NASA Technical Reports Server (NTRS)

1949-01-01

The Index of NACA Technical Publications covers reports issued from the date of origin of the Committee in 1915 until approximately September 1949. Because omissions were noted after publication of the Index issued in 1947, and since many new reports have been released since that time, it was decided to issue a new volume to supersede completely the 1947 Index, with supplements to be issued regularly in the future. Commencing with all publications issued after September 1, 1949, subject classifications were revised, the most important change involving the transfer of aircraft loads reports from the Aerodynamics classification to Structures. For those maintaining a file of NACA index cards, it is recommended that cards issued for reports dated prior to September 1, 1949 be removed from the file. This volume includes the same index information. Supplements covering periods following September 1, 1949, will be arranged according to the revised subject classifications. On the pages immediately following, the subject classifications are indexed in order of breakdown. There is included in the back of this volume an alphabetical arrangement of the subject classifications.

IPAC-Inlet Performance Analysis Code

NASA Technical Reports Server (NTRS)

Barnhart, Paul J.

1997-01-01

A series of analyses have been developed which permit the calculation of the performance of common inlet designs. The methods presented are useful for determining the inlet weight flows, total pressure recovery, and aerodynamic drag coefficients for given inlet geometric designs. Limited geometric input data is required to use this inlet performance prediction methodology. The analyses presented here may also be used to perform inlet preliminary design studies. The calculated inlet performance parameters may be used in subsequent engine cycle analyses or installed engine performance calculations for existing uninstalled engine data.

Development of Wing Inlets

NASA Technical Reports Server (NTRS)

Racisz, Stanley F.

1946-01-01

Lift, drag, internal flow, and pressure distribution measurements were made on a low-drag airfoil incorporating various air inlet designs. Two leading-edge air inlets are developed which feature higher lift coefficients and critical Mach than the basic airfoil. Higher lift coefficients and critical speeds are obtained for leading half of these inlet sections but because of high suction pressures near exist, slightly lower critical speeds are obtained for the entire inlet section than the basic airfoil.

Drought and submergence tolerance in plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Hewei; Zhou, Yufan; Oksenberg, Nir

The invention provides methods of genetically modified plants to increase tolerance to drought and/or submergence. The invention additionally provides plants having increased drought and/or submergence tolerance engineered using such methods.

The Origin of Inlet Buzz in a Mach 1.7 Low Boom Inlet Design

NASA Technical Reports Server (NTRS)

Anderson, Bernhard H.; Weir, Lois

2014-01-01

Supersonic inlets with external compression, having a good level performance at the critical operating point, exhibit a marked instability of the flow in some subcritical operation below a critical value of the capture mass flow ratio. This takes the form of severe oscillations of the shock system, commonly known as "buzz". The underlying purpose of this study is to indicate how Detached Eddy Simulation (DES) analysis of supersonic inlets will alter how we envision unsteady inlet aerodynamics, particularly inlet buzz. Presented in this paper is a discussion regarding the physical explanation underlying inlet buzz as indicated by DES analysis. It is the normal shock wave boundary layer separation along the spike surface which reduces the capture mass flow that is the controlling mechanism which determines the onset of inlet buzz, and it is the aerodynamic characteristics of a choked nozzle that provide the feedback mechanism that sustains the buzz cycle by imposing a fixed mean corrected inlet weight flow. Comparisons between the DES analysis of the Lockheed Martin Corporation (LMCO) N+2 inlet and schlieren photographs taken during the test of the Gulfstream Large Scale Low Boom (LSLB) inlet in the NASA 8x6 ft. Supersonic Wind Tunnel (SWT) show a strong similarity both in turbulent flow field structure and shock wave formation during the buzz cycle. This demonstrates the value of DES analysis for the design and understanding of supersonic inlets.

Separating the from the Imagined: Flight Research at the NACA and NASA, 1915-1998

NASA Technical Reports Server (NTRS)

Gorn, Michael H.

2000-01-01

One of the most important, but under-appreciated, aspects of the NACA/NASA mission is its aeronautical R&D efforts. Within a short time of the first flight of the Wright brothers in 1903, the United States government recognized the importance of fostering development in the new and critical field of aeronautics. NASA's predecessor, the National Advisory Committee for Aeronautics (NACA), was chartered by Congress in 1915 specifically "to supervise and direct the scientific study of the problems of flight, with a view to their practical solution. " This became an enormously important government research and development activity for the next half century, materially enhancing the development of aeronautics 'in America. The results of the NACA's research appeared in more than 16,000 research reports of one type or another, distributed widely for the benefit of all. Many of the reports documenting R&D conducted under NACA auspices are still being used today. Since the creation of NASA in 1958, the critical R&D function has continued but is not well known. This work documents the historical R&D program of the agency by focusing on flight research.

Small inlet optical panel and a method of making a small inlet optical panel

DOEpatents

Veligdan, James T.; Slobodin, David

2001-01-01

An optical panel having a small inlet, and a method of making a small inlet optical panel, are disclosed, which optical panel includes a individually coating, stacking, and cutting a first plurality of stacked optical waveguides to form an outlet face body with an outlet face, individually coating, stacking, and cutting a second plurality of stacked optical waveguides to form an inlet face body with an inlet face, and connecting an optical coupling element to the first plurality and to the second plurality, wherein the optical coupling element redirects light along a parallel axis of the inlet face to a parallel axis of the outlet face. In the preferred embodiment of the present invention, the inlet face is disposed obliquely with and askew from the outlet face.

Cloud-Droplet Ingestion in Engine Inlets with Inlet Velocity Ratios of 1.0 and 0.7

NASA Technical Reports Server (NTRS)

Brun, Rinaldo J

1957-01-01

The paths of cloud droplets into two engine inlets have been calculated for a wide range of meteorological and flight conditions. The amount of water in droplet form ingested by the inlets and the amount and distribution of water impinging on the inlet walls are obtained from these droplet-trajectory calculations. In both types of inlet, a prolate ellipsoid of revolution represents either part or all of the forebody at the center of an annular inlet to an engine. The configurations can also represent a fuselage of an airplane with side ram-scoop inlets. The studies were made at an angle of attack of 0 degree. The principal difference between the two inlets studied is that the inlet-air velocity of one is 0.7 that of the other. The studies of the two velocity ratios lead to some important general concepts of water ingestion in inlets.

Orders of Magnitude. A History of the NACA and NASA, 1915-1990. The NASA History Series.

ERIC Educational Resources Information Center

Bilstein, Roger E.

This is a history of the National Advisory Committee for Aeronautics (NACA) and its successor agency the National Aeronautics and Space Administration (NASA). Main chapters included are: (1) "NACA Origins (1915-1930)"; (2) "New Facilities, New Designs (1930-1945)"; (3) "Going Supersonic (1945-1958)"; (4) "On the…

The effects of NACA 0012 airfoil modification on aerodynamic performance improvement and obtaining high lift coefficient and post-stall airfoil

NASA Astrophysics Data System (ADS)

Sogukpinar, Haci

2018-02-01

In this study, aerodynamic performances of NACA 0012 airfoils with distinct modification are numerically investigated to obtain high lift coefficient and post-stall airfoils. NACA 0012 airfoil is divided into two part thought chord line then suction sides kept fixed and by changing the thickness of the pressure side new types of airfoil are created. Numerical experiments are then conducted by varying thickness of NACA 0012 from lower surface and different relative thicknesses asymmetrical airfoils are modified and NACA 0012-10, 0012-08, 0012-07, 0012-06, 0012-04, 0012-03, 0012-02, 0012-01 are created and simulated by using COMSOL software.

Design and Analysis Tools for Supersonic Inlets

NASA Technical Reports Server (NTRS)

Slater, John W.; Folk, Thomas C.

2009-01-01

Computational tools are being developed for the design and analysis of supersonic inlets. The objective is to update existing tools and provide design and low-order aerodynamic analysis capability for advanced inlet concepts. The Inlet Tools effort includes aspects of creating an electronic database of inlet design information, a document describing inlet design and analysis methods, a geometry model for describing the shape of inlets, and computer tools that implement the geometry model and methods. The geometry model has a set of basic inlet shapes that include pitot, two-dimensional, axisymmetric, and stream-traced inlet shapes. The inlet model divides the inlet flow field into parts that facilitate the design and analysis methods. The inlet geometry model constructs the inlet surfaces through the generation and transformation of planar entities based on key inlet design factors. Future efforts will focus on developing the inlet geometry model, the inlet design and analysis methods, a Fortran 95 code to implement the model and methods. Other computational platforms, such as Java, will also be explored.

NACA collections: A directory of significant collections of the documents of the National Advisory Committee for Aeronautics

NASA Technical Reports Server (NTRS)

Smith, Ruth S.

1994-01-01

An alphabetical listing is given of 42 centers that hold National Advisory Committee for Aeronautics (NACA) documents. Information is given on the number of NACA holdings in paper copy, bound volumes, and microfiche. Additional information is given on the bibliographic records and availability.

Wind-tunnel investigation of an NACA 23012 airfoil with 30 percent-chord venetian-blind flaps

NASA Technical Reports Server (NTRS)

Rogallo, F M; Spano, Bartholomew S

1942-01-01

Report presents the results of an investigation made in the NACA 7 by 10-foot wind tunnel of a NACA 23012 airfoil with 30-percent-chord venetian-blind flaps having one, two, three, and four slats of Clark y section. The three-slat arrangements was aerodynamically the best of those tested but showed practically no improvement over the comparable arrangement used in the preliminary tests published in NACA Technical Report No. 689. The multiple-slat flaps gave slightly higher lift coefficients than the one-slat (Fowler) flap but gave considerably greater pitching-moment coefficients. An analysis of test data indicates that substitution of a thicker and more cambered section for the Clark y slats should improve the aerodynamic and the structural characteristics of the venetian-blind flap.

Drive Fan of the NACA's Icing Research Tunnel

NASA Image and Video Library

1956-10-21

A researcher examines the drive fan inside the Icing Research Tunnel at the National Advisory Committee for Aeronautics (NACA) Flight Propulsion Research Laboratory in Cleveland, Ohio. The facility was built in the mid-1940s to simulate the atmospheric conditions that caused ice to build up on aircraft. Carrier Corporation refrigeration equipment reduced the internal air temperature to -45⁰ F, and a spray bar system injected water droplets into the air stream. The 24-foot diameter drive fan, seen in this photograph, created air flow velocities up to 400 miles per hour. The 1950s were prime years for the Icing Research Tunnel. NACA engineers had spent the 1940s trying to resolve the complexities of the spray bar system. The final system put into operation in 1950 included six horizontal spray bars with 80 nozzles that produced a 4- by 4-foot cloud in the test section. The icing tunnel was used for extensive testing of civilian and military aircraft components in the 1950s. The NACA also launched a major investigation of the various methods of heating leading edge surfaces. The hot-air anti-icing technology used on today’s commercial transports was largely developed in the facility during this period. Lewis researchers also made significant breakthroughs with icing on radomes and jet engines. Although the Icing Research Tunnel yielded major breakthroughs in the 1950s, the Lewis icing research program began tapering off as interest in the space program grew. The icing tunnel’s use declined in 1956 and 1957. The launch of Sputnik in October 1957 signaled the end of the facility’s operation. The icing staff was transferred to other research projects and the icing tunnel was temporarily mothballed.

Scramjet Inlets

DTIC Science & Technology

2010-09-01

needed in scramjets are then made, followed by a design example of a three-dimensional scramjet inlet for use in an access-to-space system that must...integration et gestion thermique) 14. ABSTRACT The supersonic combustion ramjet, or scramjet, is the engine cycle most suitable for sustained...then made, followed by a design example of a three-dimensional scramjet inlet for use in an access-to-space system that must operate between Mach 6

Desktop Access to Full-Text NACA and NASA Reports: Systems Developed by NASA Langley Technical Library

NASA Technical Reports Server (NTRS)

Ambur, Manjula Y.; Adams, David L.; Trinidad, P. Paul

1997-01-01

NASA Langley Technical Library has been involved in developing systems for full-text information delivery of NACA/NASA technical reports since 1991. This paper will describe the two prototypes it has developed and the present production system configuration. The prototype systems are a NACA CD-ROM of thirty-three classic paper NACA reports and a network-based Full-text Electronic Reports Documents System (FEDS) constructed from both paper and electronic formats of NACA and NASA reports. The production system is the DigiDoc System (DIGItal Documents) presently being developed based on the experiences gained from the two prototypes. DigiDoc configuration integrates the on-line catalog database World Wide Web interface and PDF technology to provide a powerful and flexible search and retrieval system. It describes in detail significant achievements and lessons learned in terms of data conversion, storage technologies, full-text searching and retrieval, and image databases. The conclusions from the experiences of digitization and full- text access and future plans for DigiDoc system implementation are discussed.

Preliminary Tests in the NACA Free-Spinning Wind Tunnel

NASA Technical Reports Server (NTRS)

Zimmerman, C H

1937-01-01

Typical models and the testing technique used in the NACA free-spinning wind tunnel are described in detail. The results of tests on two models afford a comparison between the spinning characteristics of scale models in the tunnel and of the airplanes that they represent.

Inlet-engine matching for SCAR including application of a bicone variable geometry inlet

NASA Technical Reports Server (NTRS)

Wasserbauer, J. F.; Gerstenmaier, W. H.

1978-01-01

Airflow characteristics of variable cycle engines (VCE) designed for Mach 2.32 can have transonic airflow requirements as high as 1.6 times the cruise airflow. This is a formidable requirement for conventional, high performance, axisymmetric, translating centerbody mixed compression inlets. An alternate inlet is defined, where the second cone of a two cone center body collapses to the initial cone angle to provide a large off-design airflow capability, and incorporates modest centerbody translation to minimize spillage drag. Estimates of transonic spillage drag are competitive with those of conventional translating centerbody inlets. The inlet's cruise performance exhibits very low bleed requirements with good recovery and high angle of attack capability.

Spiral inlets for steam turbines

NASA Astrophysics Data System (ADS)

Škach, Radek; Uher, Jan

2017-09-01

This paper deals with the design process of special nozzle blades for spiral inlets. Spiral inlets are used for the first stages of high pressure and intermediate pressure steam turbines with both reaction and impulse blades when throttling or sliding pressure control is applied. They improve the steam flow uniformity from the inlet pipe and thus decrease the aerodynamic losses. The proposed evaluation of the inlet angle is based on the free vortex law.

Axisymmetric inlet minimum weight design method

NASA Technical Reports Server (NTRS)

Nadell, Shari-Beth

1995-01-01

An analytical method for determining the minimum weight design of an axisymmetric supersonic inlet has been developed. The goal of this method development project was to improve the ability to predict the weight of high-speed inlets in conceptual and preliminary design. The initial model was developed using information that was available from inlet conceptual design tools (e.g., the inlet internal and external geometries and pressure distributions). Stiffened shell construction was assumed. Mass properties were computed by analyzing a parametric cubic curve representation of the inlet geometry. Design loads and stresses were developed at analysis stations along the length of the inlet. The equivalent minimum structural thicknesses for both shell and frame structures required to support the maximum loads produced by various load conditions were then determined. Preliminary results indicated that inlet hammershock pressures produced the critical design load condition for a significant portion of the inlet. By improving the accuracy of inlet weight predictions, the method will improve the fidelity of propulsion and vehicle design studies and increase the accuracy of weight versus cost studies.

Submergible torch for treating waste solutions and method thereof

DOEpatents

Mattus, Alfred J.

1995-01-01

A submergible torch for removing nitrate and/or nitrite ions from a waste solution containing nitrate and/or nitrite ions comprises: a torch tip, a fuel delivery mechanism, a fuel flow control mechanism, a catalyst, and a combustion chamber. The submergible torch is ignited to form a flame within the combustion chamber of the submergible torch. The torch is submerged in a waste solution containing nitrate and/or nitrite ions in such a manner that the flame is in contact with the waste solution and the catalyst and is maintained submerged for a period of time sufficient to decompose the nitrate and/or nitrite ions present in the waste solution.

Submergible torch for treating waste solutions and method thereof

DOEpatents

Mattus, Alfred J.

1994-01-01

A submergible torch for removing nitrate and/or nitrite ions from a waste solution containing nitrate and/or nitrite ions comprises: a torch tip, a fuel delivery mechanism, a fuel flow control mechanism, a catalyst, and a combustion chamber. The submergible torch is ignited to form a flame within the combustion chamber of the submergible torch. The torch is submerged in a waste solution containing nitrate and/or nitrite ions in such a manner that the flame is in contact with the waste solution and the catalyst and is maintained submerged for a period of time sufficient to decompose the nitrate and/or nitrite ions present in the waste solution.

On the tsunami wave-submerged breakwater interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filianoti, P.; Piscopo, R.

The tsunami wave loads on a submerged rigid breakwater are inertial. It is the result arising from the simple calculation method here proposed, and it is confirmed by the comparison with results obtained by other researchers. The method is based on the estimate of the speed drop of the tsunami wave passing over the breakwater. The calculation is rigorous for a sinusoidal wave interacting with a rigid submerged obstacle, in the framework of the linear wave theory. This new approach gives a useful and simple tool for estimating tsunami loads on submerged breakwaters.An unexpected novelty come out from a workedmore » example: assuming the same wave height, storm waves are more dangerous than tsunami waves, for the safety against sliding of submerged breakwaters.« less

NACA's Lockheed F-94B Starfire with Audio Recording Devices

NASA Image and Video Library

1957-07-21

A Lockheed F-94B Starfire being equipped with an audio recording machine and sensors at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The NACA was investigating the acoustic effects caused by the engine’s nozzle and the air flowing along the fuselage. Airline manufacturers would soon be introducing jet engines on their passenger aircraft, and there was concern regarding the noise levels for both the passengers and public on the ground. NACA Lewis conducted a variety of noise reduction studies in its wind tunnels, laboratories, and on a F2H-2B Banshee aircraft. The F2H-2B Banshee’s initial test flights in 1955 and 1956 measured the noise emanating directly from airflow over the aircraft’s surfaces, particularly the wings. This problem was particularly pronounced at high subsonic speeds. The researchers found the majority of the noise occurred in the low and middle octaves. These investigations were enhanced with a series of flights using the F-94B Starfire. The missions measured wall-pressure, turbulence fluctuations, and mean velocity profiles. Mach 0.3 to 0.8 flights were flown at altitudes of 10,000, 20,000, and 30,000 feet with microphones mounted near the forward fuselage and on a wing. The results substantiated the wind tunnel findings. This photograph shows the tape recorder being installed in the F-94B’s nose.

Inlet design for high-speed propfans

NASA Technical Reports Server (NTRS)

Little, B. H., Jr.; Hinson, B. L.

1982-01-01

A two-part study was performed to design inlets for high-speed propfan installation. The first part was a parametric study to select promising inlet concepts. A wide range of inlet geometries was examined and evaluated - primarily on the basis of cruise thrust and fuel burn performance. Two inlet concepts were than chosen for more detailed design studies - one apropriate to offset engine/gearbox arrangements and the other to in-line arrangements. In the second part of this study, inlet design points were chosen to optimize the net installed thrust, and detailed design of the two inlet configurations was performed. An analytical methodology was developed to account for propfan slipstream effects, transonic flow efects, and three-dimensional geometry effects. Using this methodology, low drag cowls were designed for the two inlets.

Submergible torch for treating waste solutions and method thereof

DOEpatents

Mattus, A.J.

1994-12-06

A submergible torch is described for removing nitrate and/or nitrite ions from a waste solution containing nitrate and/or nitrite ions comprises: a torch tip, a fuel delivery mechanism, a fuel flow control mechanism, a catalyst, and a combustion chamber. The submergible torch is ignited to form a flame within the combustion chamber of the submergible torch. The torch is submerged in a waste solution containing nitrate and/or nitrite ions in such a manner that the flame is in contact with the waste solution and the catalyst and is maintained submerged for a period of time sufficient to decompose the nitrate and/or nitrite ions present in the waste solution. 2 figures.

Boeing B-47 Bomber with an Ejector at the 1957 NACA Lewis Inspection

NASA Image and Video Library

1957-10-21

A Boeing B-47 Stratojet bomber with a noise-reducing ejector on its engine at the 1957 Inspection of the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. Representatives from the military, aeronautical industry, universities, and the press were invited to the laboratory to be briefed on the NACA’s latest research efforts and tour the state- of- the- art test facilities. Over 1700 people visited the NACA Lewis in Cleveland, Ohio during October 7 - 10, 1957. By the mid-1950s, the aircraft industry was close to introducing jet airliners to the nation’s airways. The noise produced by the large jet engines, however, would pose a considerable problem for communities near airports. This problem was demonstrated at the 1957 Inspection by an NACA Lewis researcher who played longplay (LP) audio records of military jet engines for an audience. Tests showed that the source of the loudest noise was not the engine itself, but the mixing of the engine’s exhaust with the surrounding air in the atmosphere. The pressures resulting from this turbulence produced sound waves. One of Lewis’ first studies sought to design an exhaust nozzle that reduced the turbulence. A Pratt and Whitney J57 was tested in the Altitude Wind Tunnel with many of these nozzle configurations from January to May 1957. Researchers found that the various nozzle types did reduce the noise levels but also reduced the aircraft’s thrust. Afterwards, they determined that the addition of an NACA-developed ejector reduced the noise levels without diminishing thrust.

Harvesting microalgal biomass using submerged microfiltration membranes.

PubMed

Bilad, M R; Vandamme, D; Foubert, I; Muylaert, K; Vankelecom, Ivo F J

2012-05-01

This study was performed to investigate the applicability of submerged microfiltration as a first step of up-concentration for harvesting both a freshwater green algae species Chlorella vulgaris and a marine diatom Phaeodactylum tricornutum using three lab-made membranes with different porosity. The filtration performance was assessed by conducting the improved flux step method (IFM) and batch up-concentration filtrations. The fouling autopsy of the membranes was performed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). The cost analysis was estimated based on the data of a related full-scale submerged membrane bioreactor (MBR). Overall results suggest that submerged microfiltration for algal harvesting is economically feasible. The IFM results indicate a low degree of fouling, comparable to the one obtained for a submerged MBR. By combining the submerged microfiltration with centrifugation to reach a final concentration of 22% w/v, the energy consumption to dewater C. vulgaris and P. tricornutum is 0.84 kW h/m(3) and 0.91 kW h/m(3), respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Inlet Duct being lowered into the Altitude Wind Tunnel Test Section

NASA Image and Video Library

1951-10-21

An inlet duct lowered into the 20-foot diameter test section of the Altitude Wind Tunnel at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. Engines and hardware were prepared in the facility’s shop area. The test articles were lifted by a two-rail Shaw box crane through the high-bay and the second-story test chamber before being lowered into the test section. Technicians then spent days or weeks hooking up the supply lines and data recording telemetry. The engines were mounted on wingspans that stretched across the test section. The wingtips attached to the balance frame’s trunnions, which could adjust the angle of attack. The balance frame included six devices that recorded data and controlled the engine. The measurements were visible in banks of manometer boards next to the control room. Photographs recorded the pressure levels in the manometer tubes, and the computing staff manually converted the data into useful measurements. A mechanical pulley system was used to raise and lower the tunnel’s large clamshell lid into place. The lid was sealed into place using hand-turned locks accessible from the viewing platform. The lid had viewing windows above and below the test article, which permitted the filming and visual inspection of the tests.

NACA Study of Crash Fires with a Fairchild C-82 Packet

NASA Image and Video Library

1950-06-21

Researchers at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory purposely crash a Fairchild C-82 Packet aircraft to study flame propagation. A rash of passenger aircraft crashes in 1946 and 1947 spurred a White House call for an investigatory board staffed by members of the Civil Aeronautics Board, military, and the NACA. The group addressed fire segregation, extinguishment, and prevention. The NACA established a Subcommittee on Aircraft Fire Prevention in February 1948 to coordinate its efforts. The Lewis team simulated situations in which an aircraft failed to become airborne during takeoff resulting in crashes into embankments and other objects. The Lewis researchers initially used surplus C-46 and C-82 military transport planes. In these situations, the aircraft generally suffered damage to its fuel system and other components, but was structurally survivable. The aircraft were mounted to a rail that ran down a 1700-foot long test runway. The aircraft was secured at the starting point with an anchor pier so it could get its engines up to takeoff speed before launching down the track. Barriers at the end of the runway were designed to simulate a variety of different types of crashes. Telemetry and high-speed cameras were crucial elements in these studies. The preliminary testing phase identified potential ignition sources and analyzed the spread of flammable materials.

Accretion of a New England (U.S.A.) salt march in response to inlet migration, storms, and sea-level rise

USGS Publications Warehouse

Roman, C.T.; Peck, J.A.; Allen, J.R.; King, J.W.; Appleby, P.G.

1997-01-01

Sediment accumulation rates were determined at several sites throughout Nauset Marsh (Massachusetts, U.S.A.), a back-barrier lagoonal system, using feldspar marker horizons to evaluate short-term rates (1 to 2 year scales) and radiometric techniques to estimate rates over longer time scales (137Cs, 210Pb, 14C). The barrier spit fronting the Spartina-dominated study site has a complex geomorphic history of inlet migration and over-wash events. This study evaluates sediment accumulation rates in relation to inlet migration, storm events, and sea-level rise. The marker horizon technique displayed strong temporal and spatial variability in response to storm events and proximity to the inlet. Sediment accumulation rates of up to 24 mm year -1 were recorded in the immediate vicinity of the inlet during a period that included several major coastal storms, while feldspar sites remote from the inlet had substantially lower rates (trace accumulation to 2.2 mm year -1). During storm-free periods, accumulation rates did not exceed 6.7 mm year -1, but remained quite variable among sites. Based on 137Cs (3.8 to 4.5 mm year -1) and 210Pb (2.6 to 4.2 mm year -1) radiometric techniques, integrating sediment accumulation over decadal time scales, the marsh appeared to be keeping pace with the relative rate of sealevel rise from 1921 to 1993 of 2.4 mm year -1. At one site, the 210Pb-based sedimentation rate and rate of relative sea-level rise were nearly similar and peat rhizome analysis revealed that Distichlis spicata recently replaced this once S.patens site, suggesting that this portion of Nauset Marsh may be getting wetter, thus representing an initial response to wetland submergence. Horizon markers are useful in evaluating the role of short-term events, such as storms or inlet migration, influencing marsh sedimentation processes. However, sampling methods that integrate marsh sedimentation over decadal time scales are preferable when evaluating a systems response to sea

Accretion of a New England (U.S.A.) salt marsh in response to inlet migration, storms, and sea-level rise

USGS Publications Warehouse

Roman, C.T.; Peck, J.A.; Allen, J.R.; King, J.W.; Appleby, P.G.

1997-01-01

Sediment accumulation rates were determined at several sites throughout Nauset Marsh (Massachusetts, U.S.A.), a back-barrier lagoonal system, using feldspar marker horizons to evaluate short-term rates (1 to 2 year scales) and radiometric techniques to estimate rates over longer time scales (137Cs, 210Pb, 14C). The barrier spit fronting the Spartima-dominated study site has a complex geomorphic history of inlet migration and overwash events. This study evaluates sediment accumulation rates in relation to inlet migration, storm events and sea-level rise. The marker horizon technique displayed strong temporal and spatial variability in response to storm events and proximity to the inlet. Sediment accumulation rates of up to 24 mm year-1 were recorded in the immediate vicinity of the inlet during a period that included several major coastal storms, while feldspar sites remote from the inlet had substantially lower rates (trace accumulation to 2.2 mm year-1). During storm-free periods, accumulation rates did not exceed 6.7 mm year-1, but remained quite variable among sites. Based on 137Cs (3.8 to 4.5 mm year-1) and 210Pb (2.6 to 4.2 mm year-1) radiometric techniques, integrating sediment accumulation over decadal time scales, the marsh appeared to be keeping pace with the relative rate of sea-level rise from 1921 to 1993 of 2.4 mm year-1. At one site, the 210Pb-based sedimentation rate and rate of relative sea-level rise were nearly similar and peat rhizome analysis revealed that Distichlis spicata recently replaced this once S. patens site, suggesting that this portion of Nauset Marsh may be getting wetter, thus representing an initial response to wetland submergence. Horizon markers are useful in evaluating the role of short-term events, such as storms or inlet migration, influencing marsh sedimentation processes. However, sampling methods that integrate marsh sedimentation over decadal time scales are preferable when evaluating a systems response to sea-level rise.

NACA Conference on Turbojet-Engine Thrust Augmentation Research: A Compilation of the Papers Presented by NACA Staff Members

NASA Technical Reports Server (NTRS)

1948-01-01

The conference on Turbojet-Engine Thrust-Augmentation Research was organized by the NACA to present in summarized form the results of the latest experimental and analytical investigations conducted at the Lewis Flight Propulsion Laboratory on methods of augmenting the thrust of turbojet engines. The technical discussions are reproduced herewith in the same form in which they were presented. The original presentation in this record are considered as complementary to, rather than substitutes for, the committee's system of complete and formal reports.

Impact Test of a NACA-Designed Pilot Seat and Harness

NASA Image and Video Library

1955-02-21

This time-lapse photograph shows the test of a pilot seat and restraint designed by researchers at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The laboratory had undertaken a multi-year investigation into the causes and preventative measures for fires resulting from low altitude aircraft crashes. The program was expanded in the mid-1950s to include the study of crash impact on passengers, new types of types of seat restraints, and better seat designs. The impact program began by purposely wrecking surplus transport Fairchild C-82 Packet and Piper Cub aircraft into barricades at the end of a test runway. Instrumented dummies and cameras were installed in the pilot and passenger areas. After determining the different loads experienced during a crash and the effects on the passengers, the NACA researchers began designing new types of seats and restraints. The result was an elastic seat that flexed upon impact, absorbing 75 percent of the loads before it slowly recoiled. This photograph shows the seats mounted on a pendulum with a large spring behind the platform to provide the jolt that mimicked the forces of a crash. The seat was constructed without any potentially damaging metal parts and included rubber-like material, an inflated back and arms, and a seat cushion. After the pendulum tests, the researchers compared the flexible seats to the rigid seats during a crash of a transport aircraft. They found the passengers in the rigid seats received 66 percent higher g-forces than the NACA-designed seats.

Investigation of REST-Class Hypersonic Inlet Designs

NASA Technical Reports Server (NTRS)

Gollan, Rowan; Ferlemann, Paul G.

2011-01-01

Rectangular-to-elliptical shape-transition (REST) inlets are of interest for use on scramjet engines because they are efficient and integrate well with the forebody of a planar vehicle. The classic design technique by Smart for these inlets produces an efficient inlet but the complex three-dimensional viscous effects are only approximately included. Certain undesirable viscous features often occur in these inlets. In the present work, a design toolset has been developed which allows for rapid design of REST-class inlet geometries and the subsequent Navier-Stokes analysis of the inlet performance. This gives the designer feedback on the complex viscous effects at each design iteration. This new tool is applied to design an inlet for on-design operation at Mach 8. The tool allows for rapid investigation of design features that was previously not possible. The outcome is that the inlet shape can be modified to affect aspects of the flow field in a positive way. In one particular example, the boundary layer build-up on the bodyside of the inlet was reduced by 20% of the thickness associated with the classically designed inlet shape.

Supersonic Elliptical Ramp Inlet

NASA Technical Reports Server (NTRS)

Adamson, Eric E. (Inventor); Fink, Lawrence E. (Inventor); Fugal, Spencer R. (Inventor)

2016-01-01

A supersonic inlet includes a supersonic section including a cowl which is at least partially elliptical, a ramp disposed within the cowl, and a flow inlet disposed between the cowl and the ramp. The ramp may also be at least partially elliptical.

Stepped inlet optical panel

DOEpatents

Veligdan, James T.

2001-01-01

An optical panel includes stacked optical waveguides having stepped inlet facets collectively defining an inlet face for receiving image light, and having beveled outlet faces collectively defining a display screen for displaying the image light channeled through the waveguides by internal reflection.

Wind-tunnel Tests of the NACA 45-125 Airfoil: A Thick Airfoil for High-Speed Airplanes

NASA Technical Reports Server (NTRS)

Delano, James B.

1940-01-01

Investigations of the pressure distribution, the profile drag, and the location of transition for a 30-inch-chord 25-percent-thick N.A,C.A. 45-125 airfoil were made in the N.A.C.A 8-foot high-speed wind tunnel for the purpose of aiding in the development of a thick wing for high-speed airplanes. The tests were made at a lift coefficient of 0.1 for Reynolds Numbers from 1,750,000 to 8,690,000, corresponding to speeds from 80 to 440 miles per hour at 59 F. The effect on the profile drag of fixing the transition point was also investigated. The effect of compressibility on the rate of increase of pressure coefficients was found to be greater than that predicted by a simplified theoretical expression for thin wings. The results indicated that, for a lift coefficient of 0.1, the critical speed of the N.A.C,A. 45-125 airfoil was about 460 miles per hour at 59 F,. The value of the profile-drag coefficient at a Reynolds Number of 4,500,000 was 0.0058, or about half as large as the value for the N.A,C,A. 0025 airfoil. The increase in the profile-drag coefficient for a given movement of the transition point was about three times as large as the corresponding increase for the N.A.C,A. 0012 airfoil. Transition determinations indicated that, for Reynolds Numbers up to ?,000,000, laminar boundary 1ayers were maintained over approximately 40 percent of the upper and the lower surfaces of the airfoil.

Computer investigations of the turbulent flow around a NACA2415 airfoil wind turbine

NASA Astrophysics Data System (ADS)

Driss, Zied; Chelbi, Tarek; Abid, Mohamed Salah

2015-12-01

In this work, computer investigations are carried out to study the flow field developing around a NACA2415 airfoil wind turbine. The Navier-Stokes equations in conjunction with the standard k-ɛ turbulence model are considered. These equations are solved numerically to determine the local characteristics of the flow. The models tested are implemented in the software "SolidWorks Flow Simulation" which uses a finite volume scheme. The numerical results are compared with experiments conducted on an open wind tunnel to validate the numerical results. This will help improving the aerodynamic efficiency in the design of packaged installations of the NACA2415 airfoil type wind turbine.

External-Compression Supersonic Inlet Design Code

NASA Technical Reports Server (NTRS)

Slater, John W.

2011-01-01

A computer code named SUPIN has been developed to perform aerodynamic design and analysis of external-compression, supersonic inlets. The baseline set of inlets include axisymmetric pitot, two-dimensional single-duct, axisymmetric outward-turning, and two-dimensional bifurcated-duct inlets. The aerodynamic methods are based on low-fidelity analytical and numerical procedures. The geometric methods are based on planar geometry elements. SUPIN has three modes of operation: 1) generate the inlet geometry from a explicit set of geometry information, 2) size and design the inlet geometry and analyze the aerodynamic performance, and 3) compute the aerodynamic performance of a specified inlet geometry. The aerodynamic performance quantities includes inlet flow rates, total pressure recovery, and drag. The geometry output from SUPIN includes inlet dimensions, cross-sectional areas, coordinates of planar profiles, and surface grids suitable for input to grid generators for analysis by computational fluid dynamics (CFD) methods. The input data file for SUPIN and the output file from SUPIN are text (ASCII) files. The surface grid files are output as formatted Plot3D or stereolithography (STL) files. SUPIN executes in batch mode and is available as a Microsoft Windows executable and Fortran95 source code with a makefile for Linux.

Full-Scale Tests of NACA Cowlings

NASA Technical Reports Server (NTRS)

Theodorsen, Theodore; Brevoort, M J; Stickle, George W

1937-01-01

A comprehensive investigation has been carried on with full-scale models in the NACA 20-foot wind tunnel, the general purpose of which is to furnish information in regard to the physical functioning of the composite propeller-nacelle unit under all conditions of take-off, taxiing, and normal flight. This report deals exclusively with the cowling characteristics under condition of normal flight and includes the results of tests of numerous combinations of more than a dozen nose cowlings, about a dozen skirts, two propellers, two sizes of nacelle, as well as various types of spinners and other devices.

Method for Determining Optimum Injector Inlet Geometry

NASA Technical Reports Server (NTRS)

Myers, W. Neill (Inventor); Trinh, Huu P. (Inventor)

2015-01-01

A method for determining the optimum inlet geometry of a liquid rocket engine swirl injector includes obtaining a throttleable level phase value, volume flow rate, chamber pressure, liquid propellant density, inlet injector pressure, desired target spray angle and desired target optimum delta pressure value between an inlet and a chamber for a plurality of engine stages. The method calculates the tangential inlet area for each throttleable stage. The method also uses correlation between the tangential inlet areas and delta pressure values to calculate the spring displacement and variable inlet geometry of a liquid rocket engine swirl injector.

Attic Inlet Technology Update

USDA-ARS?s Scientific Manuscript database

Attic inlets are a popular addition for new construction and energy saving retrofits. Proper management of attic inlets is necessary to get maximum benefits from the system and reduce the likelihood of moisture-related problems in the structure. Solar energy levels were determined for the continen...

Investigation of a Low-Drag Gun Port in the NACA Two-Dimensional Low-Turbulence Tunnel

NASA Technical Reports Server (NTRS)

Horton, Elmer A.; Woolard, Henry W.

1942-01-01

Tests were made in the NACA two-dimensional low-turbulence tunnel of three gun ports with a height of approximately 4 percent of the chord faired into an NACA 66,2-213 low-drag-airfoil section by bulging the section at the gun port. Gun ports faired in this manner had practically no effect on the maximum lift and the critical compressibility speed of the section and showed only small increase in the drag in the range of lift coefficients for high-speed and cruising-flight conditions.

Patterns of peroxidative ethane emission from submerged rice seedlings indicate that damage from reactive oxygen species takes place during submergence and is not necessarily a post-anoxic phenomenon.

PubMed

Santosa, I E; Ram, P C; Boamfa, E I; Laarhoven, L J J; Reuss, J; Jackson, M B; Harren, F J M

2007-06-01

Using ethane as a marker for peroxidative damage to membranes by reactive oxygen species (ROS) we examined the injury of rice seedlings during submergence in the dark. It is often expressed that membrane injury from ROS is a post-submergence phenomenon occurring when oxygen is re-introduced after submergence-induced anoxia. We found that ethane production, from rice seedlings submerged for 24-72 h, was stimulated to 4-37 nl gFW(-1), indicating underwater membrane peroxidation. When examined a week later the seedlings were damaged or had died. On de-submergence in air, ethane production rates rose sharply, but fell back to less than 0.1 nl gFW(-1) h(-1) after 2 h. We compared submergence-susceptible and submergence-tolerant cultivars, submergence starting in the morning (more damage) and in the afternoon (less damage) and investigated different submergence durations. The seedlings showed extensive fatality whenever total ethane emission exceeded about 15 nl gFW(-1). Smaller amounts of ethane emission were linked to less extensive injury to leaves. Partial oxygen shortage (O(2) levels <1%) imposed for 2 h in gas phase mixtures also stimulated ethane production. In contrast, seedlings under anaerobic gas phase conditions produced no ethane until re-aerated: then a small peak was observed followed by a low, steady ethane production. We conclude that damage during submergence is not associated with extensive anoxia. Instead, injury is linked to membrane peroxidation in seedlings that are partially oxygen deficient while submerged. On return to air, further peroxidation is suppressed within about 2 h indicating effective control of ROS production not evident during submergence itself.

A Tale of Two Inlets: Tidal Currents at Two Adjacent Inlets in the Indian River Lagoon

NASA Astrophysics Data System (ADS)

Webb, B. M.; Weaver, R. J.

2012-12-01

The tidal currents and hydrography at two adjacent inlets of the Indian River Lagoon estuary (Florida) were recently measured using a personal watercraft-based coastal profiling system. Although the two inlets—Sebastian Inlet and Port Canaveral Inlet—are separated by only 60 km, their characteristics and dynamics are quite unique. While Sebastian Inlet is a shallow (~4 m), curved inlet with a free connection to the estuary, Port Canaveral Inlet is dominated by a deep (~13 m), straight ship channel and has limited connectivity to the Banana River through a sector gate lock. Underway measurements of tidal currents were obtained using a bottom tracking acoustic Doppler current profiler; vertical casts of hydrography were obtained with a conductivity-temperature-depth profiling instrument; and continuous underway measurements of surface water hydrography were made using a Portable SeaKeeper system. Survey transects were performed to elucidate the along-channel variability of tidal flows, which appears to be significant in the presence of channel curvature. Ebb and flood tidal currents in Sebastian Inlet routinely exceeded 2.5 m/s from the surface to the bed, and an appreciable phase lag exists between tidal stage and current magnitude. The tidal currents at Port Canaveral Inlet were much smaller (~0.2 m/s) and appeared to be sensitive to meteorological forcing during the study period. Although the lagoon has free connections to the ocean 145 km to the north and 45 km to the south, Sebastian Inlet likely drains much of the lagoon to its north, an area of ~550 sq. km.

Preliminary Analysis of a Submerged Wave Energy Device

NASA Astrophysics Data System (ADS)

Wagner, J. R.; Wagner, J. J.; Hayatdavoodi, M.; Ertekin, R. C.

2016-02-01

Preliminary analysis of a submerged wave energy harvesting device is presented. The device is composed of a thin, horizontally submerged plate that is restricted to heave oscillations under the influence of surface waves. The submerged plate is oscillating, and it can be attached to a fixed rotor, or a piston, to harvest the wave energy. A fully submerged wave energy converter is preferred over a surface energy convertor due to its durability and less visual and physical distractions it presents. In this study, the device is subject to nonlinear shallow-water waves. Wave loads on the submerged oscillating plate are obtained via the Level I Green-Naghdi equations. The unsteady motion of the plate is obtained by solving the nonlinear equations of motion. The results are obtained for a range of waves with varying heights and periods. The amplitude and period of plate oscillations are analyzed as functions of the wave parameters and plate width. Particular attention is given to the selection of the site of desired wave field. Initial estimation on the amount of energy extraction from the device, located near shore at a given site, is provided.

A perspective on underwater photosynthesis in submerged terrestrial wetland plants

PubMed Central

Colmer, Timothy D.; Winkel, Anders; Pedersen, Ole

2011-01-01

Background and aims Wetland plants inhabit flood-prone areas and therefore can experience episodes of complete submergence. Submergence impedes exchange of O2 and CO2 between leaves and the environment, and light availability is also reduced. The present review examines limitations to underwater net photosynthesis (PN) by terrestrial (i.e. usually emergent) wetland plants, as compared with submerged aquatic plants, with focus on leaf traits for enhanced CO2 acquisition. Scope Floodwaters are variable in dissolved O2, CO2, light and temperature, and these parameters influence underwater PN and the growth and survival of submerged plants. Aquatic species possess morphological and anatomical leaf traits that reduce diffusion limitations to CO2 uptake and thus aid PN under water. Many aquatic plants also have carbon-concentrating mechanisms to increase CO2 at Rubisco. Terrestrial wetland plants generally lack the numerous beneficial leaf traits possessed by aquatic plants, so submergence markedly reduces PN. Some terrestrial species, however, produce new leaves with a thinner cuticle and higher specific leaf area, whereas others have leaves with hydrophobic surfaces so that gas films are retained when submerged; both improve CO2 entry. Conclusions Submergence inhibits PN by terrestrial wetland plants, but less so in species that produce new leaves under water or in those with leaf gas films. Leaves with a thinner cuticle, or those with gas films, have improved gas diffusion with floodwaters, so that underwater PN is enhanced. Underwater PN provides sugars and O2 to submerged plants. Floodwaters often contain dissolved CO2 above levels in equilibrium with air, enabling at least some PN by terrestrial species when submerged, although rates remain well below those in air. PMID:22476500

[Algal control ability of allelopathically active submerged macrophytes: a review].

PubMed

Xiao, Xi; Lou, Li-ping; Li, Hua; Chen, Ying-xu

2009-03-01

The inhibitory effect of allelochemicals released by submerged macrophytes on phytoplankton is considered as one of the mechanisms that contribute to the stabilization of clear-water status in shallow lakes. This paper reviewed the research progress in the allelopathy of submerged macrophytes on algae from the aspects of the occurrence frequency and coverage of allelopathically active submerged macrophytes in lakes, and the kinds and allelopathical effects of the allelochemicals released from the macrophytes. The previous researches indicated that allelopathically active submerged macrophyte species such as Myriophyllum, Ceratophyllum, and Elodea were efficient to control phytoplankton, especially when their biomass was high enough, and the dominant algae were sensitive species. The allelochemicals such as hydroxybenzene released by the submerged macrophytes could inhibit the growth of algae. Different phytoplankton species exhibited different sensitivity against allelochemicals, e.g., cyanobacteria and diatom were more sensitive than green algae, while epiphytic species were less sensitive than phytoplankton. Environmental factors such as light, temperature, and nutrients could significantly affect the allelopathical effect of submerged macrophytes. The research of the allelopathy of submerged macrophytes is still at its beginning, and further researches are needed on the effects of environmental factors on the allelopathy, extraction and identification of allelochemicals, selective algal control mechanisms, and metabolism of the allelochmicals.

A Study on the Nonmetallic Inclusion Motions in a Swirling Flow Submerged Entry Nozzle in a New Cylindrical Tundish Design

NASA Astrophysics Data System (ADS)

Ni, Peiyuan; Ersson, Mikael; Jonsson, Lage Tord Ingemar; Jönsson, Pär Göran

2018-04-01

Different sizes and shapes of nonmetallic inclusions in a swirling flow submerged entry nozzle (SEN) placed in a new tundish design were investigated by using a Lagrangian particle tracking scheme. The results show that inclusions in the current cylindrical tundish have difficulties remaining in the top tundish region, since a strong rotational steel flow exists in this region. This high rotational flow of 0.7 m/s provides the required momentum for the formation of a strong swirling flow inside the SEN. The results show that inclusions larger than 40 µm were found to deposit to a smaller extent on the SEN wall compared to smaller inclusions. The reason is that these large inclusions have Separation number values larger than 1. Thus, the swirling flow causes these large size inclusions to move toward the SEN center. For the nonspherical inclusions, large size inclusions were found to be deposited on the SEN wall to a larger extent, compared to spherical inclusions. More specifically, the difference of the deposited inclusion number is around 27 pct. Overall, it was found that the swirling flow contains three regions, namely, the isotropic core region, the anisotropic turbulence region and the near-wall region. Therefore, anisotropic turbulent fluctuations should be taken into account when the inclusion motion was tracked in this complex flow. In addition, many inclusions were found to deposit at the SEN inlet region. The plotted velocity distribution shows that the inlet flow is very chaotic. A high turbulent kinetic energy value of around 0.08 m2/s2 exists in this region, and a recirculating flow was also found here. These flow characteristics are harmful since they increase the inclusion transport toward the wall. Therefore, a new design of the SEN inlet should be developed in the future, with the aim to modify the inlet flow so that the inclusion deposition is reduced.

Boundary-Layer-Ingesting Inlet Flow Control

NASA Technical Reports Server (NTRS)

Owens, Lewis R.; Allan, Brian G.; Gorton, Susan A.

2006-01-01

This paper gives an overview of a research study conducted in support of the small-scale demonstration of an active flow control system for a boundary-layer-ingesting (BLI) inlet. The effectiveness of active flow control in reducing engine inlet circumferential distortion was assessed using a 2.5% scale model of a 35% boundary-layer-ingesting flush-mounted, offset, diffusing inlet. This experiment was conducted in the NASA Langley 0.3-meter Transonic Cryogenic Tunnel at flight Mach numbers with a model inlet specifically designed for this type of testing. High mass flow actuators controlled the flow through distributed control jets providing the active flow control. A vortex generator point design configuration was also tested for comparison purposes and to provide a means to examine a hybrid vortex generator and control jets configuration. Measurements were made of the onset boundary layer, the duct surface static pressures, and the mass flow through the duct and the actuators. The distortion and pressure recovery were determined by 40 total pressure measurements on 8 rake arms each separated by 45 degrees and were located at the aerodynamic interface plane. The test matrix was limited to a maximum free-stream Mach number of 0.85 with scaled mass flows through the inlet for that condition. The data show that the flow control jets alone can reduce circumferential distortion (DPCP(sub avg)) from 0.055 to about 0.015 using about 2.5% of inlet mass flow. The vortex generators also reduced the circumferential distortion from 0.055 to 0.010 near the inlet mass flow design point. Lower inlet mass flow settings with the vortex generator configuration produced higher distortion levels that were reduced to acceptable levels using a hybrid vortex generator/control jets configuration that required less than 1% of the inlet mass flow.

Boundary-Layer-Ingesting Inlet Flow Control

NASA Technical Reports Server (NTRS)

Owens, Lewis R.; Allan, Brian G.; Gorton, Susan A.

2006-01-01

This paper gives an overview of a research study conducted in support of the small-scale demonstration of an active flow control system for a boundary-layer-ingesting (BLI) inlet. The effectiveness of active flow control in reducing engine inlet circumferential distortion was assessed using a 2.5% scale model of a 35% boundary-layer-ingesting flush-mounted, offset, diffusing inlet. This experiment was conducted in the NASA Langley 0.3-meter Transonic Cryogenic Tunnel at flight Mach numbers with a model inlet specifically designed for this type of testing. High mass flow actuators controlled the flow through distributed control jets providing the active flow control. A vortex generator point design configuration was also tested for comparison purposes and to provide a means to examine a hybrid vortex generator and control jets configuration. Measurements were made of the onset boundary layer, the duct surface static pressures, and the mass flow through the duct and the actuators. The distortion and pressure recovery were determined by 40 total pressure measurements on 8 rake arms each separated by 45 degrees and were located at the aerodynamic interface plane. The test matrix was limited to a maximum free-stream Mach number of 0.85 with scaled mass flows through the inlet for that condition. The data show that the flow control jets alone can reduce circumferential distortion (DPCPavg) from 0.055 to about 0.015 using about 2.5% of inlet mass flow. The vortex generators also reduced the circumferential distortion from 0.055 to 0.010 near the inlet mass flow design point. Lower inlet mass flow settings with the vortex generator configuration produced higher distortion levels that were reduced to acceptable levels using a hybrid vortex generator/control jets configuration that required less than 1% of the inlet mass flow.

Evaluation of Icing Scaling on Swept NACA 0012 Airfoil Models

NASA Technical Reports Server (NTRS)

Tsao, Jen-Ching; Lee, Sam

2012-01-01

Icing scaling tests in the NASA Glenn Icing Research Tunnel (IRT) were performed on swept wing models using existing recommended scaling methods that were originally developed for straight wing. Some needed modifications on the stagnation-point local collection efficiency (i.e., beta(sub 0) calculation and the corresponding convective heat transfer coefficient for swept NACA 0012 airfoil models have been studied and reported in 2009, and the correlations will be used in the current study. The reference tests used a 91.4-cm chord, 152.4-cm span, adjustable sweep airfoil model of NACA 0012 profile at velocities of 100 and 150 knot and MVD of 44 and 93 mm. Scale-to-reference model size ratio was 1:2.4. All tests were conducted at 0deg angle of attack (AoA) and 45deg sweep angle. Ice shape comparison results were presented for stagnation-point freezing fractions in the range of 0.4 to 1.0. Preliminary results showed that good scaling was achieved for the conditions test by using the modified scaling methods developed for swept wing icing.

Energy configuration optimization of submerged propeller in oxidation ditch based on CFD

NASA Astrophysics Data System (ADS)

Wu, S. Y.; Zhou, D. Q.; Zheng, Y.

2012-11-01

The submerged propeller is presented as an important dynamic source in oxidation ditch. In order to guarantee the activated sludge not deposit, it is necessary to own adequate drive power. Otherwise, it will cause many problems such as the awful mixed flow and the great consuming of energy. At present, carrying on the installation optimization of submerged propeller in oxidation ditch mostly depends on experience. So it is necessary to use modern design method to optimize the installation position and number of submerged propeller, and to research submerged propeller flow field characteristics. The submerged propeller internal flow is simulated by using CFD software FLUENT6.3. Based on Navier-Stokes equations and standard k - ɛ turbulence model, the flow was simulated by using a SIMPLE algorithm. The results indicate that the submerged propeller installation position change could avoid the condition of back mixing, which caused by the strong drive. Besides, the problem of sludge deposit and the low velocity in the bend which caused by the drive power attenuation could be solved. By adjusting the submerged propeller number, the least power density that the mixing drive needed could be determined and saving energy purpose could be achieved. The study can provide theoretical guidance for optimize the submerged propeller installation position and determine submerged propeller number.

McDonnell FH-1 Phantom Destroyed for the NACA Crash Fire Program

NASA Image and Video Library

1955-04-21

Researchers at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory purposely wreck a McDonnell FH-1 Phantom as part of the laboratory’s Crash Fire Program. NACA Lewis researchers created the program in 1949 to investigate methods for improving survival rates for take-off and landing-type crashes. In these types of crashes, the passengers often survived the impact only to perish in the ensuing fire. Previously there had been little information on the nature of post-crash fires, and it was difficult to use analytical studies in this area. Irving Pinkel, Chief of the Lewis Flight Propulsion Division, was the primary researcher. He enlisted flight safety specialist and aeronautics researchers G. Merritt Preston and Gerard Pesman, mechanical engineer Dugald Black, and others. The tests were conducted at the nearby Ravenna Arsenal using decommissioned Air Force fighter and transport aircraft. The pilotless aircraft were accelerated down a rail on a 1700-foot track at take-off speeds and run into barriers to simulate a variety of different types of crashes. The first barrier stripped off the landing gears and another briefly sent the aircraft off the ground before it crashed into a dirt mound. Telemetry and high-speed cameras were crucial elements in these studies. NACA Lewis photographer Bill Wynne developed a method for inserting timekeeping devices on test film that were able to show time to one thousandth of a second.

Meeting Review: Airborne Aerosol Inlet Workshop

NASA Technical Reports Server (NTRS)

Baumgardner, Darrel; Huebert, Barry; Wilson, Chuck

1991-01-01

Proceedings from the Airborne Aerosol Inlet Workshop are presented. The two central topics of discussion were the role of aerosols in atmospheric processes and the difficulties in characterizing aerosols. The following topics were discussed during the working sessions: airborne observations to date; identification of inlet design issues; inlet modeling needs and directions; objectives for aircraft experiments; and future laboratory and wind tunnel studies.

NACA Mechanics in an Allison Engine Training Class

NASA Image and Video Library

1943-10-21

The Allison Engine Company's A.G. Covell instructs mechanics from various divisions at the National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory on the operation of the Allison Basic Engine. The military had asked that the laboratory undertake an extensive program to improve the performance of the Allison V–1710 engine. The V–1710 was the only liquid-cooled engine used during World War II, and the military counted on it to power several types of fighter aircraft. The NACA instituted an Apprentice Program during the war to educate future mechanics, technicians, and electricians. The program was suspended for a number of years due to the increasing rates of military service by its participants. The laboratory continued its in-house education during the war, however, by offering a number of classes to its employees and lectures for the research staff. The classes and lectures were usually taught by fellow members of the staff, but occasionally external experts were brought in. The students in the Allison class in the Engine Research Building were taught how to completely disassemble and reassemble the engine components and systems. From left to right are Don Vining, Ed Cudlin, Gus DiNovo, George Larsen, Charles Diggs, Martin Lipes, Harley Roberts, Martin Berwaldt and John Dempsey. A.G. Covell is standing.

Water inlet blowdown

NASA Astrophysics Data System (ADS)

Timar, T.

1981-09-01

A new blowdown system was developed for cleaning debris from the inlet grill of waterjet propulsion system on Boeing hydrofoil boats. A system was required to work with existing waterjet ducts which are open ended. The new blowdown system consists of an abrupt discharge of high pressure compressed air amidst the water inlet duct. It utilizes the open end of the propulsor discharge nozzle as a safety valve. Feasibility was proven by semi-steady state equations and was confirmed by full scale testing. A system was developed and installed and is now fully operational.

Boundary-layer-ingesting inlet flow control system

NASA Technical Reports Server (NTRS)

Owens, Lewis R. (Inventor); Allan, Brian G. (Inventor)

2010-01-01

A system for reducing distortion at the aerodynamic interface plane of a boundary-layer-ingesting inlet using a combination of active and passive flow control devices is disclosed. Active flow control jets and vortex generating vanes are used in combination to reduce distortion across a range of inlet operating conditions. Together, the vortex generating vanes can reduce most of the inlet distortion and the active flow control jets can be used at a significantly reduced control jet mass flow rate to make sure the inlet distortion stays low as the inlet mass flow rate varies. Overall inlet distortion, measured and described as average SAE circumferential distortion descriptor, was maintained at a value of 0.02 or less. Advantageous arrangements and orientations of the active flow control jets and the vortex generating vanes were developed using computational fluid dynamics simulations and wind tunnel experimentations.

Preliminary wind-tunnel investigation of an NACA 23012 airfoil with various arrangements of venetian-blind flaps

NASA Technical Reports Server (NTRS)

Wenzinger, Carl J; Harris, Thomas A

1940-01-01

Report presents the results of an investigation made in the NACA 7 by 10-foot wind tunnel of a large-chord NACA 23012 airfoil with several arrangements of venetian-blind flaps to determine the aerodynamic section characteristics as affected by the over-all flap chord, the chords of the slats used to form the flap, the slat spacing, the number of slats and the position of the flap with respect to the wing. Complete section data are given in the form of graphs for all the combinations tested.

Chronostratigraphic Analysis of Geomorphic Features within the Former Sinepuxent Inlet: A Wave-Dominated Tidal Inlet along Assateague Island, MD, USA

NASA Astrophysics Data System (ADS)

Seminack, C.; McBride, R.; Petruny, L. M.

2017-12-01

The former Sinepuxent Inlet, located along the mixed-energy, wave-dominated Assateague Island, MD-VA, USA, contains some of the most robust recurved-spit ridges along the span of the barrier island. In addition, this former tidal inlet exhibits a poorly developed flood-tidal delta containing at least two sets of curvilinear ridges known as "washarounds". Historical maps and nautical charts indicate that the former Sinepuxent Inlet was open from 1755 to 1832. However, previous studies conducted at the former Sinepuxent Inlet hypothesized that the site was exposed to episodic breaching events because of the extensive width of the former inlet throat, constrained by the northern and southern recurved-spit ridges. A total of 16 sediment cores, 10 optically stimulated luminescence (OSL) samples, and three 14C samples (mixed benthic foraminifera and eastern mud snail [Ilyanassa obsolete]) were collected from the former Sinepuxent Inlet to place morphostratigraphic units into a chronological context. Six OSL samples were collected from the northern and southern recurved-spit ridges at mean sea level (MSL) to constrain genesis ages. Southern recurved-spit ages varied more than their northern counterparts, ranging from 1640 to 1990 AD. The northern recurved-spit ridges varied in age from 1770 to 1900 AD. Two OSL samples collected from flood-tidal delta ridges yielded ages from 1680 to 2000 AD. In addition, two 14C samples collected at 128 and 101 cm below MSL within the inlet throat yielded ages between 1720 and post-1950 AD. Ultimately, these dates overlap with the inlet activity phase as indicated in historical documents. Conversely, two OSL samples (155 and 201 cm below MSL) and one 14C sample (134 cm below MSL) collected from the inlet throat returned ages between 760 and 1465 AD. The contrast in ages between the older inlet throat and subaerial ridge samples supports the hypothesis that the former Sinepuxent Inlet was reactivated numerous times. Thus, the three age

49 CFR 193.2629 - External corrosion control: buried or submerged components.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been designed...

49 CFR 193.2629 - External corrosion control: buried or submerged components.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been designed...

49 CFR 193.2629 - External corrosion control: buried or submerged components.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been designed...

49 CFR 193.2629 - External corrosion control: buried or submerged components.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been designed...

SUPIN: A Computational Tool for Supersonic Inlet Design

NASA Technical Reports Server (NTRS)

Slater, John W.

2016-01-01

A computational tool named SUPIN is being developed to design and analyze the aerodynamic performance of supersonic inlets. The inlet types available include the axisymmetric pitot, three-dimensional pitot, axisymmetric outward-turning, two-dimensional single-duct, two-dimensional bifurcated-duct, and streamline-traced inlets. The aerodynamic performance is characterized by the flow rates, total pressure recovery, and drag. The inlet flow-field is divided into parts to provide a framework for the geometry and aerodynamic modeling. Each part of the inlet is defined in terms of geometric factors. The low-fidelity aerodynamic analysis and design methods are based on analytic, empirical, and numerical methods which provide for quick design and analysis. SUPIN provides inlet geometry in the form of coordinates, surface angles, and cross-sectional areas. SUPIN can generate inlet surface grids and three-dimensional, structured volume grids for use with higher-fidelity computational fluid dynamics (CFD) analysis. Capabilities highlighted in this paper include the design and analysis of streamline-traced external-compression inlets, modeling of porous bleed, and the design and analysis of mixed-compression inlets. CFD analyses are used to verify the SUPIN results.

Submerged cultivation of medicinal mushrooms: bioprocesses and products (review).

PubMed

Elisashvili, Vladimir

2012-01-01

Medicinal mushrooms belonging to higher Basidiomycetes are an immensely rich yet largely untapped resource of useful, easily accessible, natural compounds with various biological activities that may promote human well-being. The medicinal properties are found in various cellular components and secondary metabolites (polysaccharides, proteins and their complexes, phenolic compounds, polyketides, triterpenoids, steroids, alkaloids, nucleotides, etc.), which have been isolated and identified from the fruiting bodies, culture mycelium, and culture broth of mushrooms. Some of these compounds have cholesterol-lowering, anti-diabetic, antioxidant, antitumor, immunomodulating, antimicrobial, and antiviral activities ready for industrial trials and further commercialization, while others are in various stages of development. Recently, the submerged cultivation of medicinal mushrooms has received a great deal of attention as a promising and reproducible alternative for the efficient production of mushroom mycelium and metabolites. Submerged cultivation of mushrooms has significant industrial potential, but its success on a commercial scale depends on increasing product yields and development of novel production systems that address the problems associated with this technique of mushroom cultivation. In spite of many researchers' efforts for the production of bioactive metabolites by mushrooms, the physiological and engineering aspects of submerged cultures are still far from being thoroughly studied. The vast majority of studies have focused on polysaccharide and ganoderic acid production in submerged cultivation of medicinal mushrooms, and very little has been written so far on the antioxidant and hemagglutinating activity of submerged mushroom cultures. The purpose of this review is to provide an update of the present state of the art and future prospects of submerged cultivation of medicinal mushrooms to produce mycelium and bioactive metabolites, and to make a

Atmospheric effects on inlets for supersonic cruise aircraft

NASA Technical Reports Server (NTRS)

Cole, G. L.

1977-01-01

Mixed-compression inlet dynamic behavior in the vicinity of unstart, was simulated and analyzed to investigate time response of an inlet's normal shock to independent disturbances in ambient temperature and pressure and relative velocity (longitudinal gust), with and without inlet controls active. The results indicate that atmospheric disturbances may be more important than internal disturbances in setting inlet controls requirements because they are usually not anticipated and because normal shock response to rapid atmospheric disturbances is not attenuated by the inlet, as it is for engine induced disturbances. However, before inlet control requirements can be fully assessed, more statistics on extreme atmospheric disturbances are needed.

Forced convection in vertical Bridgman configuration with the submerged heater

NASA Astrophysics Data System (ADS)

Meyer, S.; Ostrogorsky, A. G.

1997-02-01

Ga-doped Ge single crystals were grown in vertical Bridgman configuration, using the submerged heater method (SHM). When used without rotation, the submerged heater drastically reduces convection at the solid-liquid interface. When the submerged heater is set in to rotation or oscillatory rotation, it acts as a centrifugal viscous pump, inducing forced convection (radial-inward flow) along the interface. The flow produced by a rotation and oscillatory rotation of the submerged heater was visualized using a 1 : 1 scale model. The vigorous mixing produced by the oscillatory rotation creates a nearly perfectly stirred melt, and yields a uniform lateral distribution of the dopant. The crystals were free of unintentionally produced striae.

Reactions of nitrite with hemoglobin measured by membrane inlet mass spectrometry

PubMed Central

Tu, Chingkuang; Mikulski, Rose; Swenson, Erik R.; Silverman, David N.

2010-01-01

Membrane inlet mass spectrometry was used to observe nitric oxide in the well-studied reaction of nitrite with hemoglobin. The membrane inlet was submerged in the reaction solutions and measured NO in solution via its flux across a semipermeable membrane leading to the mass spectrometer detecting the mass-to-charge ratio m/z 30. This method measures NO directly in solution and is an alternate approach compared with methods that purge solutions to measure NO. Addition to deoxy-Hb(FeII) (near 38 µM heme concentration) of nitrite in a range of 80 µM to 16 mM showed no accumulation of either NO or N2O3 on a physiologically relevant time scale with a sensitivity near 1 nM. The addition of nitrite to oxy-Hb(FeII) and met-Hb(FeIII) did not accumulate free NO to appreciable extents. These observations show that for several minutes after mixing nitrite with hemoglogin, free NO does not accumulate to levels exceeding the equilibrium level of NO. The presence of cyanide ions did not alter the appearance of the data; however, the presence of 2 mM mercuric ions at the beginning of the experiment with deoxy-Hb(FeII) shortened the initial phase of NO accumulation and increased the maximal level of free, unbound NO by about twofold. These experiments appear consistent with no role of met-Hb(FeIII) in the generation of NO and an increase in nitrite reductase activity caused by the presumed binding of mercuric to cysteine residues. These results raise questions about the ability of reduction of nitrite mediated by deoxy-Hb(FeII) to play a role in vasodilation. PMID:18848984

Advanced Technology Inlet Design, NRA 8-21 Cycle II: DRACO Flowpath Hypersonic Inlet Design

NASA Technical Reports Server (NTRS)

Sanders, Bobby W.; Weir, Lois J.

1999-01-01

The report outlines work performed in support of the flowpath development for the DRACO engine program. The design process initiated to develop a hypersonic axisymmetric inlet for a Mach 6 rocket-based combined cycle (RBCC) engine is discussed. Various design parametrics were investigated, including design shock-on-lip Mach number, cone angle, throat Mach number, throat angle. length of distributed compression, and subsonic diffuser contours. Conceptual mechanical designs consistent with installation into the D-21 vehicle were developed. Additionally, program planning for an intensive inlet development program to support a Critical Design Review in three years was performed. This development program included both analytical and experimental elements and support for a flight-capable inlet mechanical design.

Propulsive Efficiencies of Magnetohydrodynamic Submerged Vehicular Propulsors

DTIC Science & Technology

1990-04-01

TERMS (Con’we on mrae . neoaay and kWerty by back nLt.) FIELD GROUP SUB-GROUP Magnetohydrodynamic propulsion, marine propulsion, seawater pump ...propelling a vehicular structure by a seawater elec- tromagnetic pump . This propulsion system can be applied to a surface ship or a submerged vehicle; however...structure by a seawater electromagnetic pump . This propulsion system can be applied to a surface ship or a submerged vehicle; however, in this work only

Computational Modeling and Validation for Hypersonic Inlets

NASA Technical Reports Server (NTRS)

Povinelli, Louis A.

1996-01-01

Hypersonic inlet research activity at NASA is reviewed. The basis for the paper is the experimental tests performed with three inlets: the NASA Lewis Research Center Mach 5, the McDonnell Douglas Mach 12, and the NASA Langley Mach 18. Both three-dimensional PNS and NS codes have been used to compute the flow within the three inlets. Modeling assumptions in the codes involve the turbulence model, the nature of the boundary layer, shock wave-boundary layer interaction, and the flow spilled to the outside of the inlet. Use of the codes and the experimental data are helping to develop a clearer understanding of the inlet flow physics and to focus on the modeling improvements required in order to arrive at validated codes.

Modulation of the reaction cycle of the Na+:Ca2+, K+ exchanger.

PubMed

Vedovato, Natascia; Rispoli, Giorgio

2007-09-01

Ca(2+) concentration in retinal photoreceptor rod outer segment (OS) strongly affects the generator potential kinetics and the receptor light adaptation. The response to intense light stimuli delivered in the dark produce potential changes exceeding 40 mV: since the Ca(2+) extrusion in the OS is entirely controlled by the Na(+):Ca(2+), K(+) exchanger, it is important to assess how the exchanger ion transport rate is affected by the voltage and, in general, by intracellular factors. It is indeed known that the cardiac Na(+):Ca(2+) exchanger is regulated by Mg-ATP via a still unknown metabolic pathway. In the present work, the Na(+):Ca(2+), K(+) exchanger regulation was investigated in isolated OS, recorded in whole-cell configuration, using ionic conditions that activated maximally the exchanger in both forward and reverse mode. In all species examined (amphibia: Rana esculenta and Ambystoma mexicanum; reptilia: Gecko gecko), the forward (reverse) exchange current increased about linearly for negative (positive) voltages and exhibited outward (inward) rectification for positive (negative) voltages. Since hyperpolarisation increases Ca(2+) extrusion rate, the recovery of the dark level of Ca(2+) (and, in turn, of the generator potential) after intense light stimuli results accelerated. Mg-ATP increased the size of forward and reverse exchange current by a factor of approximately 2.3 and approximately 2.6, respectively, without modifying their voltage dependence. This indicates that Mg-ATP regulates the number of active exchanger sites and/or the exchanger turnover number, although via an unknown mechanism.

Critical Propulsion Components. Volume 4; Inlet and Fan/Inlet Accoustics Team

NASA Technical Reports Server (NTRS)

2005-01-01

Several studies have concluded that a supersonic aircraft, if environmentally acceptable and economically viable, could successfully compete in the 21st century marketplace. However, before industry can commit to what is estimated as a 15 to 20 billion dollar investment, several barrier issues must be resolved. In an effort to address these barrier issues, NASA and Industry teamed to form the High-Speed Research (HSR) program. As part of this program, the Critical Propulsion Components (CPC) element was created and assigned the task of developing those propulsion component technologies necessary to: (1) reduce cruise emissions by a factor of 10 and (2) meet the ever-increasing airport noise restrictions with an economically viable propulsion system. The CPC-identified critical components were ultra-low emission combustors, low-noise/high-performance exhaust nozzles, low-noise fans, and stable/high-performance inlets. Propulsion cycle studies (coordinated with NASA Langley Research Center sponsored airplane studies) were conducted throughout this CPC program to help evaluate candidate components and select the best concepts for the more complex and larger scale research efforts. The propulsion cycle and components ultimately selected were a mixed-flow turbofan (MFTF) engine employing a lean, premixed, prevaporized (LPP) combustor coupled to a two-dimensional mixed compression inlet and a two-dimensional mixer/ejector nozzle. Due to the large amount of material presented in this report, it was prepared in four volumes; Volume 1: Summary, Introduction, and Propulsion System Studies, Volume 2: Combustor, Volume 3: Exhaust Nozzle, and Volume 4: Inlet and Fan/Inlet Acoustic Team.

Reconstruction of paleo-inlet dynamics using sedimentologic analyses, geomorphic features, and benthic foraminiferal assemblages: former ephemeral inlets of Cedar Island, Virginia, USA

NASA Astrophysics Data System (ADS)

McBride, R.; Wood, E. T.

2017-12-01

Cedar Island, VA is a low-profile, washover-dominated barrier island that has breached at least three times in the past sixty years. Cedar Island Inlet, a former wave-dominated tidal inlet, was open for the following time periods: 1) 1956-1962, 2) 1992-1997, and 3) 1998-2007. Air photos, satellite imagery, and geomorphic features (i.e., relict flood tidal deltas, recurved-spit ridges) record the spatial and temporal extent of the three ephemeral inlets. Based on three sediment vibracores, benthic foraminiferal and sedimentologic analyses offer high resolution insights of inlet dynamics and lifecycle evolution. Four foraminiferal biofacies are completely dominated by Elphidium excavatum (54-100%) and contain unique assemblages of accessory species based on cluster analyses: tidal inlet floor (low abundance estuarine and shelf species; 23% Haynesina germanica); flood tidal delta/inlet fill (high abundance estuarine and shelf species; 2% Buccella frigida, 2% Ammonia parkinsoniana, and 2% Haynesina germanica); high-energy inlet fill (low abundance, low diversity shelf species; 9% Elphidium gunteri); and washover/beach/aeolian (low abundance, predominantly shelf species; 3% Buccella frigida and 3% Ammonia parkinsoniana). The estuarine biofacies is barren of all foraminifera. Grain size trends indicate a first order coarsening-upward succession with second order coarsening- and fining-upwards packages in inlet throat deposits, while a first order fining-upward succession is observed in flood tidal delta deposits with two second order coarsening-upward packages in the proximal flood tidal delta. Contrary to typical wave-dominated tidal inlets that open, migrate laterally in the direction of net longshore transport, and close, the 1998-2007 tidal inlet, and possibly the 1956-1962 inlet, migrated laterally and rotated, whereas the 1992-1997 inlet remained stationary and did not rotate. In the vicinity of the vibracores, preserved deposits are attributed to the 1956-1962 and

Planar Inlet Design and Analysis Process (PINDAP)

NASA Technical Reports Server (NTRS)

Slater, John W.; Gruber, Christopher R.

2005-01-01

The Planar Inlet Design and Analysis Process (PINDAP) is a collection of software tools that allow the efficient aerodynamic design and analysis of planar (two-dimensional and axisymmetric) inlets. The aerodynamic analysis is performed using the Wind-US computational fluid dynamics (CFD) program. A major element in PINDAP is a Fortran 90 code named PINDAP that can establish the parametric design of the inlet and efficiently model the geometry and generate the grid for CFD analysis with design changes to those parameters. The use of PINDAP is demonstrated for subsonic, supersonic, and hypersonic inlets.

Radial inlet guide vanes for a combustor

DOEpatents

Zuo, Baifang; Simons, Derrick; York, William; Ziminsky, Willy S

2013-02-12

A combustor may include an interior flow path therethrough, a number of fuel nozzles in communication with the interior flow path, and an inlet guide vane system positioned about the interior flow path to create a swirled flow therein. The inlet guide vane system may include a number of windows positioned circumferentially around the fuel nozzles. The inlet guide vane system may also include a number of inlet guide vanes positioned circumferentially around the fuel nozzles and adjacent to the windows to create a swirled flow within the interior flow path.

Morphological evolution of an ephemeral tidal inlet from opening to closure: The Albufeira inlet, Portugal

NASA Astrophysics Data System (ADS)

Fortunato, André B.; Nahon, Alphonse; Dodet, Guillaume; Rita Pires, Ana; Conceição Freitas, Maria; Bruneau, Nicolas; Azevedo, Alberto; Bertin, Xavier; Benevides, Pedro; Andrade, César; Oliveira, Anabela

2014-02-01

Like other similar coastal systems, the Albufeira lagoon is artificially opened every year to promote water renewal and closes naturally within a few months. The evolution of the Albufeira Lagoon Inlet from its opening in April 2010 to its closure 8 months later is qualitatively and quantitatively analyzed through a combination of monthly field surveys and the application of a process-based morphodynamic model. Field data alone would not cover the whole space-time domain of the morphology of the inlet during its life time, whereas the morphodynamic model alone cannot reliably simulate the morphological development. Using a nudging technique introduced herein, this problem is overcome and a reliable and complete data set is generated for describing the morphological development of the tidal inlet. The new technique is shown to be a good alternative to extensive model calibration, as it can drastically improve the model performance. Results reveal that the lagoon imported sediments during its life span. However, the whole system (lagoon plus littoral barrier) actually lost sediments to the sea. This behavior is partly attributed to the modulation of tidal asymmetry by the spring-neap cycle, which reduces flood dominance on spring tides. Results also allowed the assessment of the relationship between the spring tidal prism and the cross-section of tidal inlets (the PA relationship). While this relationship is well established from empirical, theoretical and numerical evidences, its validity in inlets that are small or away from equilibrium was unclear. Results for the Albufeira lagoon reveal an excellent match between the new data and the empirical PA relationship derived for larger inlets and equilibrium conditions, supporting the validity of the relationship beyond its original scope.

Boundary-Layer-Ingesting Inlet Flow Control

NASA Technical Reports Server (NTRS)

Owens, Lewis R.; Allan, Brian G.; Gorton, Susan A.

2008-01-01

An experimental study was conducted to provide the first demonstration of an active flow control system for a flush-mounted inlet with significant boundary-layer-ingestion in transonic flow conditions. The effectiveness of the flow control in reducing the circumferential distortion at the engine fan-face location was assessed using a 2.5%-scale model of a boundary-layer-ingesting offset diffusing inlet. The inlet was flush mounted to the tunnel wall and ingested a large boundary layer with a boundary-layer-to-inlet height ratio of 35%. Different jet distribution patterns and jet mass flow rates were used in the inlet to control distortion. A vane configuration was also tested. Finally a hybrid vane/jet configuration was tested leveraging strengths of both types of devices. Measurements were made of the onset boundary layer, the duct surface static pressures, and the mass flow rates through the duct and the flow control actuators. The distortion and pressure recovery were measured at the aerodynamic interface plane. The data show that control jets and vanes reduce circumferential distortion to acceptable levels. The point-design vane configuration produced higher distortion levels at off-design settings. The hybrid vane/jet flow control configuration reduced the off-design distortion levels to acceptable ones and used less than 0.5% of the inlet mass flow to supply the jets.

Na+/Ca2+ exchange and Na+/K+-ATPase in the heart

PubMed Central

Shattock, Michael J; Ottolia, Michela; Bers, Donald M; Blaustein, Mordecai P; Boguslavskyi, Andrii; Bossuyt, Julie; Bridge, John H B; Chen-Izu, Ye; Clancy, Colleen E; Edwards, Andrew; Goldhaber, Joshua; Kaplan, Jack; Lingrel, Jerry B; Pavlovic, Davor; Philipson, Kenneth; Sipido, Karin R; Xie, Zi-Jian

2015-01-01

This paper is the third in a series of reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on cardiac Na+/Ca2+ exchange (NCX) and Na+/K+-ATPase (NKA). While the relevance of Ca2+ homeostasis in cardiac function has been extensively investigated, the role of Na+ regulation in shaping heart function is often overlooked. Small changes in the cytoplasmic Na+ content have multiple effects on the heart by influencing intracellular Ca2+ and pH levels thereby modulating heart contractility. Therefore it is essential for heart cells to maintain Na+ homeostasis. Among the proteins that accomplish this task are the Na+/Ca2+ exchanger (NCX) and the Na+/K+ pump (NKA). By transporting three Na+ ions into the cytoplasm in exchange for one Ca2+ moved out, NCX is one of the main Na+ influx mechanisms in cardiomyocytes. Acting in the opposite direction, NKA moves Na+ ions from the cytoplasm to the extracellular space against their gradient by utilizing the energy released from ATP hydrolysis. A fine balance between these two processes controls the net amount of intracellular Na+ and aberrations in either of these two systems can have a large impact on cardiac contractility. Due to the relevant role of these two proteins in Na+ homeostasis, the emphasis of this review is on recent developments regarding the cardiac Na+/Ca2+ exchanger (NCX1) and Na+/K+ pump and the controversies that still persist in the field. PMID:25772291

NACA Technician Cleans a Ramjet in 8- by 6-Foot Supersonic Wind Tunnel

NASA Image and Video Library

1950-04-21

A technician at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory cleans the pitot tube on a 16-inch diameter ramjet in the 8- by 6-Foot Supersonic Wind Tunnel. Pitot tubes are a measurement device used to determine the flow velocity at a specific location in the air stream, not the average velocity of the entire wind stream. NACA Lewis was in the midst of a multi-year program to determine the feasibility of ramjets and design improvements that could be employed for all models. The advantage of the ramjet was its ability to process large volumes of combustion air, resulting in the burning of fuel at the optimal stoichiometric temperatures. This was not possible with turbojets. The higher the Mach number, the more efficient the ramjet operated. The 8- by 6 Supersonic Wind Tunnel had been in operation for just over one year when this photograph was taken. The facility was the NACA’s largest supersonic tunnel and the only facility capable of running an engine at supersonic speeds. The 8- by 6 tunnel was also equipped with a Schlieren camera system that captured the air flow gradient as it passes over the test setup. The ramjet tests in the 8- by 6 tunnel complemented the NACA Lewis investigations using aircraft, the Altitude Wind Tunnel and smaller supersonic tunnels. Researchers studied the ramjet’s performance at different speeds and varying angles -of -attack.

Large-Scale Low-Boom Inlet Test Overview

NASA Technical Reports Server (NTRS)

Hirt, Stefanie

2011-01-01

This presentation provides a high level overview of the Large-Scale Low-Boom Inlet Test and was presented at the Fundamental Aeronautics 2011 Technical Conference. In October 2010 a low-boom supersonic inlet concept with flow control was tested in the 8'x6' supersonic wind tunnel at NASA Glenn Research Center (GRC). The primary objectives of the test were to evaluate the inlet stability and operability of a large-scale low-boom supersonic inlet concept by acquiring performance and flowfield validation data, as well as evaluate simple, passive, bleedless inlet boundary layer control options. During this effort two models were tested: a dual stream inlet intended to model potential flight hardware and a single stream design to study a zero-degree external cowl angle and to permit surface flow visualization of the vortex generator flow control on the internal centerbody surface. The tests were conducted by a team of researchers from NASA GRC, Gulfstream Aerospace Corporation, University of Illinois at Urbana-Champaign, and the University of Virginia

Resume and analysis of NACA lateral control research

NASA Technical Reports Server (NTRS)

Weick, Fred E; Jones, Robert T

1937-01-01

An analysis of the principal results of recent NACA lateral control research is made by utilizing the experience and progress gained during the course of the investigation. Two things are considered of primary importance in judging the effectiveness of different control devices: the (calculated) banking and yawing motion of a typical small airplane caused by a deflection of the control, and the stick force required to produce this deflection. The report includes a table in which a number of different lateral control devices are compared on these bases.

Numerical investigation of flow on NACA4412 aerofoil with different aspect ratios

NASA Astrophysics Data System (ADS)

Demir, Hacımurat; Özden, Mustafa; Genç, Mustafa Serdar; Çağdaş, Mücahit

2016-03-01

In this study, the flow over NACA4412 was investigated both numerically and experimentally at a different Reynolds numbers. The experiments were carried out in a low speed wind tunnel with various angles of attack and different Reynolds numbers (25000 and 50000). Airfoil was manufactured using 3D printer with a various aspect ratios (AR = 1 and AR = 3). Smoke-wire and oil flow visualization methods were used to visualize the surface flow patterns. NACA4412 aerofoil was designed by using SOLIDWORKS. The structural grid of numerical model was constructed by ANSYS ICEM CFD meshing software. Furthermore, ANSYS FLUENT™ software was used to perform numerical calculations. The numerical results were compared with experimental results. Bubble formation was shown in CFD streamlines and smoke-wire experiments at z / c = 0.4. Furthermore, bubble shrunk at z / c = 0.2 by reason of the effects of tip vortices in both numerical and experimental studies. Consequently, it was seen that there was a good agreement between numerical and experimental results.

Method of making a small inlet optical panel

DOEpatents

Veligdan, James T.; Slobodin, David E.

2004-02-03

An optical panel having a small inlet, and a method of making a small inlet optical panel, are disclosed, which optical panel includes a individually coating, stacking, and cutting a first plurality of stacked optical waveguides to form an outlet face body with an outlet face, individually coating, stacking, and cutting a second plurality of stacked optical waveguides to form an inlet face body with an inlet face, and connecting an optical coupling element to the first plurality and second plurality of stacked optical waveguides, wherein the optical coupling element redirects light along a parallel axis of the inlet face to a parallel axis of the outlet face. In the preferred embodiment of the present invention, the inlet face is disposed obliquely with and askew from the outlet face.

The NACA High-Speed Motion-Picture Camera Optical Compensation at 40,000 Photographs Per Second

NASA Technical Reports Server (NTRS)

Miller, Cearcy D

1946-01-01

The principle of operation of the NACA high-speed camera is completely explained. This camera, operating at the rate of 40,000 photographs per second, took the photographs presented in numerous NACA reports concerning combustion, preignition, and knock in the spark-ignition engine. Many design details are presented and discussed, details of an entirely conventional nature are omitted. The inherent aberrations of the camera are discussed and partly evaluated. The focal-plane-shutter effect of the camera is explained. Photographs of the camera are presented. Some high-speed motion pictures of familiar objects -- photoflash bulb, firecrackers, camera shutter -- are reproduced as an illustration of the quality of the photographs taken by the camera.

Investigation on inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet

NASA Astrophysics Data System (ADS)

Yang, Ce; Wang, Yingjun; Lao, Dazhong; Tong, Ding; Wei, Longyu; Liu, Yixiong

2016-08-01

The inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet structures were studied in numerical method, mainly focused on three issues including the amounts and differences of the inlet recirculation in different working conditions, the circumferential non-uniform distributions of the inlet recirculation, the recirculation velocity distributions of the upstream slot of the rear impeller. The results show that there are some differences between the recirculation of the front impeller and that of the rear impeller in whole working conditions. In design speed, the recirculation flow rate of the rear impeller is larger than that of the front impeller in the large flow range, but in the small flow range, the recirculation flow rate of the rear impeller is smaller than that of the front impeller. In different working conditions, the recirculation velocity distributions of the front and rear impeller are non-uniform along the circumferential direction and their non-uniform extents are quite different. The circumferential non-uniform extent of the recirculation velocity varies with the working conditions change. The circumferential non-uniform extent of the recirculation velocity of front impeller and its distribution are determined by the static pressure distribution of the front impeller, but that of the rear impeller is decided by the coupling effects of the inlet flow distortion of the rear impeller, the circumferential unsymmetrical distribution of the upstream slot and the asymmetric structure of the volute. In the design flow and small flow conditions, the recirculation velocities at different circumferential positions of the mean line of the upstream slot cross-section of the rear impeller are quite different, and the recirculation velocities distribution forms at both sides of the mean line are different. The recirculation velocity distributions in the cross-section of the upstream slot depend on the static pressure

Investigation on Convergence – Divergence Nozzle Shape for Microscale Channel in Harvesting Kinetic Energy

NASA Astrophysics Data System (ADS)

Zakaria, M. S.; Zairi, S.; Misbah, M. N.; Saifizi, M.; Rakawi, Izzudin

2018-03-01

This paper presents performance evaluation of nozzle shapes on microscale channel by employing different types of NACA airfoils profile and conventional profile. The deploying nozzle used are NACA 0012, NACA 0021 and NACA 0024 airfoils while for conventional convergence-divergence nozzle diameter ratio (d2 / d1) in the range from 1/4 to 3/4 are applied. These nozzles are assembled on rectangular cross sectional microscale channel which has designated constant fluid flow velocity at the channel inlet. This study revealed reduction on diameter ratio increased dramatically fluid velocity but further reduction on diameter ratio exposed fluid flow to fluctuate which slightly slowing down the fluid velocity. Nevertheless, curved NACA profiles are favourable for convergence – divergence nozzle in microscale channel as it significantly improved flow characteristics by enhancing fluid velocity and resultant kinetic energy as compared to conventional profile.

Experimental and Computational Evaluation of Flush-Mounted, S-Duct Inlets

NASA Technical Reports Server (NTRS)

Berrier, Bobby L.; Allan, Brian G.

2004-01-01

A new high Reynolds number test capability for boundary layer ingesting inlets has been developed for the NASA Langley Research Center 0.3-Meter Transonic Cryogenic Tunnel. Using this new capability. an experimental investigation of four S-duct inlet configurations was conducted. A computational study of one of the inlets was also conducted using a Navier-Stokes solver. The objectives of this investigation were to: 1) develop a new high Reynolds number inlet test capability for flush-mounted inlets; 2) provide a database for CFD tool validation; 3) evaluate the performance of S-duct inlets with large amounts of boundary layer ingestion; and 4) provide a baseline inlet for future inlet flow-control studies. Tests were conducted at Mach numbers from 0.25 to 0.83. Reynolds numbers (based on duct exit diameter) from 5.1 million to a full-scale value of 13.9 million, and inlet mass-flow ratios from 0.39 to 1.58 depending on Mach number. Results of the experimental study indicate that inlet pressure recovery generally decreased and inlet distortion generally increased with increasing Mach number. Except at low Mach numbers, increasing inlet mass-flow increased pressure recovery and increased distortion. Increasing the amount of boundary layer ingestion or ingesting a boundary layer with a distorted profile decreased pressure recovery and increased distortion. Finally, increasing Reynolds number had almost no effect on inlet distortion but increased inlet recovery by about one-half percent at a Mach number near cruise. The computational results captured the inlet pressure recovery and distortion trends with Mach number and inlet mass-flow well: the reversal of the pressure recovery trend with increasing inlet mass-flow at low and high Mach numbers was predicted by CFD. However, CFD results were generally more pessimistic (larger losses) than measured experimentally.

Comparison of the Aeroacoustics of Two Small-Scale Supersonic Inlets

NASA Technical Reports Server (NTRS)

Ng, Wing

1996-01-01

An aerodynamic and acoustic investigation was performed on two small-scale supersonic inlets to determine which inlet would be more suitable for a High Speed Civil Transport (HSCT) aircraft during approach and takeoff flight conditions. The comparison was made between an axisymmetric supersonic P inlet and a bifurcated two-dimensional supersonic inlet. The 1/14 scale model supersonic inlets were used in conjunction with a 4.1 in (10.4 cm) turbofan engine simulator. A bellmouth was utilized on each inlet to eliminate lip separation commonly associated with airplane engine inlets that are tested under static conditions. Steady state measurements of the aerodynamic flowfield and acoustic farfield were made in order to evaluate the aeroacoustic performance of the inlets. The aerodynamic results show the total pressure recovery of the two inlets to be nearly identical, 99% at the approach condition and 98% at the takeoff condition. At the approach fan speed (60% design speed), there was no appreciable difference in the acoustic performance of either inlet over the entire 0 deg to 110 deg farfield measurement sector. The inlet flow field results at the takeoff fan speed (88% design speed), show the average inlet throat Mach number for the P inlet (Mach 0.52) to be approximately 2 times that of the 2D inlet (Mach 0.26). The difference in the throat Mach number is a result of the smaller throughflow area of the P inlet. This reduced area resulted in a 'soft choking' of the P inlet which lowered the tone and overall sound pressure levels of the simulator in the forward sector by an average of 9 dB and 3 dB, respectively, when compared to the 2D inlet.

Aerial View of NACA's Lewis Flight Propulsion Research Laboratory

NASA Image and Video Library

1946-05-21

The National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory in Cleveland, Ohio as seen from the west in May 1946. The Cleveland Municipal Airport is located directly behind. The laboratory was built in the early 1940s to resolve problems associated with aircraft engines. The initial campus contained seven principal buildings: the Engine Research Building, hangar, Fuels and Lubricants Building, Administration Building, Engine Propeller Research Building, Altitude Wind Tunnel, and Icing Research Tunnel. These facilities and their associated support structures were located within an area occupying approximately one-third of the NACA’s property. After World War II ended, the NACA began adding new facilities to address different problems associated with the newer, more powerful engines and high speed flight. Between 1946 and 1955, four new world-class test facilities were built: the 8- by 6-Foot Supersonic Wind Tunnel, the Propulsion Systems Laboratory, the Rocket Engine Test Facility, and the 10- by 10-Foot Supersonic Wind Tunnel. These large facilities occupied the remainder of the NACA’s semicircular property. The Lewis laboratory expanded again in the late 1950s and early 1960s as the space program commenced. Lewis purchased additional land in areas adjacent to the original laboratory and acquired a large 9000-acre site located 60 miles to the west in Sandusky, Ohio. The new site became known as Plum Brook Station.

Contrasting Changes Caused by Drought and Submergence Stresses in Bermudagrass (Cynodon dactylon)

PubMed Central

Ye, Tiantian; Shi, Haitao; Wang, Yanping; Chan, Zhulong

2015-01-01

In this study, we investigated the mechanisms by which bermudagrass withstands the drought and submergence stresses through physiological, proteomic and metabolomic approaches. The results showed that significant physiological changes were observed after drought treatment, while only slight changes after submergence treatment, including compatible solute contents, ROS levels and antioxidant enzyme activities. Proteomics results showed that 81 proteins regulated by drought or submergence treatment were identified by MALDI-TOF-MS. Among them, 76 proteins were modulated by drought stress with 46 increased abundance and 30 decreased abundance. Forty-five showed abundance changes after submergence treatment with 10 increased and 35 decreased. Pathway enrichment analysis revealed that pathways of amino acid metabolism and mitochondrial electron transport/ATP synthesis were only enriched by drought treatment, while other pathways including photosynthesis, biodegradation of xenobiotics, oxidative pentose phosphate, glycolysis and redox were commonly over-represented after both drought and submergence treatments. Metabolomic analysis indicated that most of the metabolites were up-regulated by drought stress, while 34 of 40 metabolites contents exhibited down-regulation or no significant changes when exposed to submergence stress, including sugars and sugar alcohols. These data indicated that drought stress extensively promoted photosynthesis and redox metabolisms while submergence stress caused declined metabolisms and dormancy in Cynodon dactylon. Taken together, the quiescence strategy with retarded growth might allow bermudagrass to be adaptive to long-term submerged environment, while activation of photosynthesis and redox, and accumulation of compatible solutes and molecular chaperones increased bermudagrass tolerance to drought stress. PMID:26617615

Sample inlet tube for ion source

DOEpatents

Prior, David [Hermiston, OR; Price, John [Richland, WA; Bruce, Jim [Oceanside, CA

2002-09-24

An improved inlet tube is positioned within an aperture through the device to allow the passage of ions from the ion source, through the improved inlet tube, and into the interior of the device. The inlet tube is designed with a larger end and a smaller end wherein the larger end has a larger interior diameter than the interior diameter of the smaller end. The inlet tube is positioned within the aperture such that the larger end is pointed towards the ion source, to receive ions therefrom, and the smaller end is directed towards the interior of the device, to deliver the ions thereto. Preferably, the ion source utilized in the operation of the present invention is a standard electrospray ionization source. Similarly, the present invention finds particular utility in conjunction with analytical devices such as mass spectrometers.

Circulation exchange patterns in Sinclair Inlet, Washington

USGS Publications Warehouse

Noble, Marlene A.; Rosenberger, Kurt J.; Paulson, Anthony J.; Gartner, Anne L.

2013-01-01

In 1994, the U.S. Geological Survey (USGS), in cooperation with the U.S. Navy, deployed three sets of moorings in Sinclair Inlet, which is a relatively small embayment on the western side of Puget Sound (fig. 1). This inlet is home to the Puget Sound Naval Shipyard. One purpose of the measurement program was to determine the transport pathways and fate of contaminants known to be present in Sinclair Inlet. Extensive descriptions of the program and the resultant information about contaminant pathways have been reported in Gartner and others (1998). This report primarily focused on the bottom boundary layer and the potential for resuspension and transport of sediments on the seabed in Sinclair Inlet as a result of tides and waves. Recently (2013), interest in transport pathways for suspended and dissolved materials in Sinclair Inlet has been rekindled. In particular, the USGS scientists in Washington and California have been asked to reexamine the datasets collected in the earlier study to refine not only our understanding of transport pathways through the inlet, but to determine how those transport pathways are affected by subtidal currents, local wind stress, and fresh water inputs. Because the prior study focused on the bottom boundary layer and not the water column, a reanalysis of the datasets could increase our understanding of the dynamic forces that drive transport within and through the inlet. However, the early datasets are limited in scope and a comprehensive understanding of these transport processes may require more extensive datasets or the development of a detailed numerical model of transport processes for the inlet, or both.

Gas Turbine Engine Inlet Wall Design

NASA Technical Reports Server (NTRS)

Florea, Razvan Virgil (Inventor); Stucky, Mark B. (Inventor); Matalanis, Claude G. (Inventor)

2016-01-01

A gas turbine engine has an inlet duct formed to have a shape with a first ellipse in one half and a second ellipse in a second half. The second half has an upstream most end which is smaller than the first ellipse. The inlet duct has a surface defining the second ellipse which curves away from the first ellipse, such that the second ellipse is larger at an intermediate location. The second ellipse is even larger at a downstream end of the inlet duct leading into a fan.

Submergible barge retrievable storage and permanent disposal system for radioactive waste

DOEpatents

Goldsberry, Fred L.; Cawley, William E.

1981-01-01

A submergible barge and process for submerging and storing radioactive waste material along a seabed. A submergible barge receives individual packages of radwaste within segregated cells. The cells are formed integrally within the barge, preferably surrounded by reinforced concrete. The cells are individually sealed by a concrete decking and by concrete hatch covers. Seawater may be vented into the cells for cooling, through an integral vent arrangement. The vent ducts may be attached to pumps when the barge is bouyant. The ducts are also arranged to promote passive ventilation of the cells when the barge is submerged. Packages of the radwaste are loaded into individual cells within the barge. The cells are then sealed and the barge is towed to the designated disposal-storage site. There, the individual cells are flooded and the barge will begin descent controlled by a powered submarine control device to the seabed storage site. The submerged barge will rest on the seabed permanently or until recovered by a submarine control device.

Hypersonic Inlet for a Laser Powered Propulsion System

NASA Astrophysics Data System (ADS)

Harrland, Alan; Doolan, Con; Wheatley, Vincent; Froning, Dave

2011-11-01

Propulsion within the lightcraft concept is produced via laser induced detonation of an incoming hypersonic air stream. This process requires suitable engine configurations that offer good performance over all flight speeds and angles of attack to ensure the required thrust is maintained. Stream traced hypersonic inlets have demonstrated the required performance in conventional hydrocarbon fuelled scramjet engines, and has been applied to the laser powered lightcraft vehicle. This paper will outline the current methodology employed in the inlet design, with a particular focus on the performance of the lightcraft inlet at angles of attack. Fully three-dimensional turbulent computational fluid dynamics simulations have been performed on a variety of inlet configurations. The performance of the lightcraft inlets have been evaluated at differing angles of attack. An idealized laser detonation simulation has also been performed to validate that the lightcraft inlet does not unstart during the laser powered propulsion cycle.

Investigation of normal shock inlets for highly maneuverable aircraft

NASA Technical Reports Server (NTRS)

Martin, A. W.

1977-01-01

Concepts are investigated for obtaining both low cowl drag and good inlet performance at high angles of attack. The effect of a canard on inlet performance for a kidney shaped inlet in each of two vertical locations is discussed along with a sharp lip two dimensional inlet on a canardless forebody.

Tabulations of static pressure coefficients on the surfaces of 3 pylon-mounted axisymmetric flow-through nacelles at Mach numbers from 0.40 to 0.98

NASA Technical Reports Server (NTRS)

Re, R. J.; Peddrew, K. H.

1982-01-01

Three flow through nacelles mounted on an 82 deg swept pylon (10 percent thickness-to-chord ratio) were tested in the Langley 16 foot Transonic Tunnel. The long uncambered pylon was supported from a small body of revolution so that pressure measurements on the nacelle and pylon represent a pylon nacelle flow field without a wing present. Two nacelles had NACA 1-85-100 inlets and different circular arc afterbodies. The third nacelle had an NACA 1-70-100 inlet with a circular arc afterbody having the same external shape as one of the other nacelles. Nacelle length to maximum diameter ratio was 3.5. Data were obtained at angles of attack from 2 deg to 8 deg at selected Mach numbers.

An Analysis of Explosion-Induced Bending Damage in Submerged Shell Targets,

DTIC Science & Technology

1984-12-01

AD-R169 009 AN ANRLYSIS OF EXPLOSION-INDUCED SENDING DfIMAhE IN SUBMERGED SHELL TRRGETS(U) NRVRL SURFACE HERPONS CENTER OANLOREN YR N NOUSSOUROS DEC...BENDING DAMAGE IN SUBMERGED SHELL TARGETS 0 o BY MINOS MOUSSOUROS RESEARCH AND TECHNOLOGY DEPARTMENT < DECEMBER 1984 Aptroved f u, blic release...IN SUBMERGED ) SHELL TARGETS 6. PERFORMING ORG. REPORT NUMBER 7 AUTHOR(&) S. CONTRACT OR GRANT NUMERI(s) jMlNoS MOUSSoUROS 9 PERFORMING

Coastal Inlets Research Program

DTIC Science & Technology

2014-04-01

PCs to evaluate inlets, channels, structures, adjacent beaches dredging and placement within, regional systems .  Transfer technology and...Coastal  Modeling  or o o  Management System   (CMS) Alex Sanchez Ned MitchellCIRP Honghai Li Waves at  Research & Development Geomorphic  Evolution T B k...channel infilling Aug 2005 Baltimore, MD Inlet Modeling  System  technology transfer workshop #7 – FSBPA, Jan/Feb 2006 Sarasota, FL Modeling of waves

Hypersonic Combustor Model Inlet CFD Simulations and Experimental Comparisons

NASA Technical Reports Server (NTRS)

Venkatapathy, E.; TokarcikPolsky, S.; Deiwert, G. S.; Edwards, Thomas A. (Technical Monitor)

1995-01-01

Numerous two-and three-dimensional computational simulations were performed for the inlet associated with the combustor model for the hypersonic propulsion experiment in the NASA Ames 16-Inch Shock Tunnel. The inlet was designed to produce a combustor-inlet flow that is nearly two-dimensional and of sufficient mass flow rate for large scale combustor testing. The three-dimensional simulations demonstrated that the inlet design met all the design objectives and that the inlet produced a very nearly two-dimensional combustor inflow profile. Numerous two-dimensional simulations were performed with various levels of approximations such as in the choice of chemical and physical models, as well as numerical approximations. Parametric studies were conducted to better understand and to characterize the inlet flow. Results from the two-and three-dimensional simulations were used to predict the mass flux entering the combustor and a mass flux correlation as a function of facility stagnation pressure was developed. Surface heat flux and pressure measurements were compared with the computed results and good agreement was found. The computational simulations helped determine the inlet low characteristics in the high enthalpy environment, the important parameters that affect the combustor-inlet flow, and the sensitivity of the inlet flow to various modeling assumptions.

Application of rotor mounted pressure transducers to analysis of inlet turbulence. [flow distortion in turbofan engine inlet

NASA Technical Reports Server (NTRS)

Hanson, D. B.

1976-01-01

Miniature pressure transducers installed near the leading edge of a fan blade were used to diagnose the non-uniform flow entering a subsonic tip speed turbofan on a static test stand. The pressure response of the blade to the inlet flow variations was plotted in a form which shows the space-time history of disturbances ingested by the rotor. Also, periodically sampled data values were auto- and cross-correlated as if they had been acquired from fixed hot wire anemometers at 150 equally spaced angles around the inlet. With a clean inlet and low wind, evidence of long, narrow turbulence eddies was easily found both in the boundary layer of the fan duct and outside the boundary layer. The role of the boundary layer was to follow and amplify disturbances in the outer flow. These eddies frequently moved around the inlet with a corkscrew motion as they passed through.

Canopy Modeling of Aquatic Vegetation: Construction of Submerged Vegetation Index

NASA Astrophysics Data System (ADS)

Ma, Z.; Zhou, G.

2018-04-01

The unique spectral characteristics of submerged vegetation in wetlands determine that the conventional terrestrial vegetation index cannot be directly employed to species identification and parameter inversion of submerged vegetation. Based on the Aquatic Vegetation Radiative Transfer model (AVRT), this paper attempts to construct an index suitable for submerged vegetation, the model simulated data and a scene of Sentinel-2A image in Taihu Lake, China are utilized for assessing the performance of the newly constructed indices and the existent vegetation indices. The results show that the angle index composed by 525 nm, 555 nm and 670 nm can resist the effects of water columns and is more sensitive to vegetation parameters such as LAI. Furthermore, it makes a well discrimination between submerged vegetation and water bodies in the satellite data. We hope that the new index will provide a theoretical basis for future research.

Application of quadratic optimization to supersonic inlet control

NASA Technical Reports Server (NTRS)

Lehtinen, B.; Zeller, J. R.

1971-01-01

The application of linear stochastic optimal control theory to the design of the control system for the air intake (inlet) of a supersonic air-breathing propulsion system is discussed. The controls must maintain a stable inlet shock position in the presence of random airflow disturbances and prevent inlet unstart. Two different linear time invariant control systems are developed. One is designed to minimize a nonquadratic index, the expected frequency of inlet unstart, and the other is designed to minimize the mean square value of inlet shock motion. The quadratic equivalence principle is used to obtain the best linear controller that minimizes the nonquadratic performance index. The two systems are compared on the basis of unstart prevention, control effort requirements, and sensitivity to parameter variations.

Inlet Cover On the Curiosity Rover

NASA Image and Video Library

2018-06-04

The drill bit of NASA's Curiosity Mars rover over one of the sample inlets on the rover's deck. The inlets lead to Curiosity's onboard laboratories. This image was taken on Sol 2068 by the rover's Mast Camera (Mastcam). https://photojournal.jpl.nasa.gov/catalog/PIA22327

NACA Investigation of Fuel Performance in Piston-Type Engines

NASA Technical Reports Server (NTRS)

Barnett, Henry C

1951-01-01

This report is a compilation of many of the pertinent research data acquired by the National Advisory Committee for Aeronautics on fuel performance in piston engines. The original data for this compilation are contained in many separate NACA reports which have in the present report been assembled in logical chapters that summarize the main conclusions of the various investigations. Complete details of each investigation are not included in this summary; however, such details may be found, in the original reports cited at the end of each chapter.

Electrically heated particulate matter filter with recessed inlet end plugs

DOEpatents

Gonze, Eugene V [Pinckney, MI; Ament, Frank [Troy, MI

2012-02-21

A particulate matter (PM) filter includes filter walls having inlet ends and outlet ends. First adjacent pairs of the filter walls define inlet channels. Second adjacent pairs of the filter walls define outlet channels. Outlet end plugs are arranged in the inlet channels adjacent to the output ends. Inlet end plugs arranged in the outlet channels spaced from the inlet ends.

Wave-driven fluxes through New River Inlet, NC

NASA Astrophysics Data System (ADS)

Wargula, A.; Raubenheimer, B.; Elgar, S.

2012-12-01

The importance of wave forcing to inlet circulation is examined using observations of waves, water levels, and currents collected in and near New River Inlet, NC during April and May, 2012. A boat-mounted system was used to measure current profiles along transects across the inlet mouth during three 14-hr periods, providing information on cross-inlet current structure, as well as discharge. Additionally, an array of 13 colocated pressure gages and profilers were deployed along 2 km of the inlet channel (5 to 10 m water depths) and ebb shoal channel (2 to 3 m water depths) and 19 colocated pressure gages and acoustic Doppler velocimeters were deployed across and offshore of the ebb shoal (1 to 5 m water depths) (Figure 1). The inlet is well mixed and tidal currents ranged from +/- 1.5 m/s, maximum discharge rates at peak ebb and flood were about 700 to 900 m3/s, offshore significant wave heights Hsig were 0.5 to 2.5 m, and wind speeds ranged from 0 to 14 m/s. Time-integrated residual discharge over semi-diurnal tidal cycles with similar ranges was ebb dominant during calm conditions (May 11, net out-of-inlet discharge ~ 55 m3, Hsig ~ 0.5 m, NW winds ~ 3 m/s) and flood dominant during stormier conditions (May 14, net into-inlet discharge ~ 15 m3, Hsig ~ 1.2 m, S winds ~ 6.5 m/s). Low-pass filtered in situ profiler data suggest wave-forcing affects the fluxes into and out of the inlet. The observations will be used to examine the momentum balance governing the temporal and cross-inlet (channel vs. shoal) variation of these fluxes, as well as the effect of waves on ebb and flood flow dominance. Funding provided by the Office of Naval Research and a National Security Science and Engineering Faculty Fellowship.; Figure 1: Google Earth image of New River Inlet, NC. Colors are depth contours (scale on the right, units are m relative to mean sea level) and symbols are locations of colocated current meters and pressure gages.

NACA Aircraft in hangar 1953 - L-R: Three D-558-2s, D-558-1, B-47, wing of YF-84A, background are th

NASA Technical Reports Server (NTRS)

1953-01-01

The aircraft in this 1953 photo of the National Advisory Committee for Aeronautics (NACA) hangar at South Base of Edwards Air Force Base showed the wide range of research activities being undertaken. On the left side of the hanger are the three D-558-2 research aircraft. These were designed to test swept wings at supersonic speeds approaching Mach 2. The front D-558-2 is the third built (NACA 145/Navy 37975). It has been modified with a leading-edge chord extension. This was one of a number of wing modifications, using different configurations of slats and/or wing fences, to ease the airplane's tendency to pitch-up. NACA 145 had both a jet and a rocket engine. The middle aircraft is NACA 144 (Navy 37974), the second built. It was all-rocket powered, and Scott Crossfield made the first Mach 2 flight in this aircraft on November 20, 1953. The aircraft in the back is D-558-2 number 1. NACA 143 (Navy 37973) was also carried both a jet and a rocket engine in 1953. It had been used for the Douglas contractor flights, then was turned over to the NACA. The aircraft was not converted to all-rocket power until June 1954. It made only a single NACA flight before NACA's D-558-2 program ended in 1956. Beside the three D-558-2s is the third D-558-1. Unlike the supersonic D-558-2s, it was designed for flight research at transonic speeds, up to Mach 1. The D-558-1 was jet-powered, and took off from the ground. The D-558-1's handling was poor as it approached Mach 1. Given the designation NACA 142 (Navy 37972), it made a total of 78 research flights, with the last in June 1953. In the back of the hangar is the X-4 (Air Force 46-677). This was a Northrop-built research aircraft which tested a swept wing design without horizontal stabilizers. The aircraft proved unstable in flight at speeds above Mach 0.88. The aircraft showed combined pitching, rolling, and yawing motions, and the design was considered unsuitable. The aircraft, the second X-4 built, was then used as a pilot trainer

Conservation of peat soils in agricultural use by infiltration of ditch water via submerged drains: results of a case study in the western peat soil area of The Netherlands

NASA Astrophysics Data System (ADS)

van den Akker, Jan J. H.; Hendriks, Rob F. A.

2017-04-01

less by the draining effect of submerged drains. This reduces losses of grass yield by trampling and increases the length of the grazing season. The use of submerged drains causes a higher water usage, however, raising ditchwater levels to derive the same peat soil conservation would require a higher amount of inlet water. The impact on ditchwater quality is in most cases positive, however, sometimes slightly negative. For the dairy farmer submerged drains are economically in the short term not effective, however in the longer term increasingly positive. For the society as a whole the use of submerged drains is a very cost effective way to reduce CO2 emissions and subsidence of peat soils in agricultural use.

Unstart coupling mechanism analysis of multiple-modules hypersonic inlet.

PubMed

Hu, Jichao; Chang, Juntao; Wang, Lei; Cao, Shibin; Bao, Wen

2013-01-01

The combination of multiplemodules in parallel manner is an important way to achieve the much higher thrust of scramjet engine. For the multiple-modules scramjet engine, when inlet unstarted oscillatory flow appears in a single-module engine due to high backpressure, how to interact with each module by massflow spillage, and whether inlet unstart occurs in other modules are important issues. The unstarted flowfield and coupling characteristic for a three-module hypersonic inlet caused by center module II and side module III were, conducted respectively. The results indicate that the other two hypersonic inlets are forced into unstarted flow when unstarted phenomenon appears on a single-module hypersonic inlet due to high backpressure, and the reversed flow in the isolator dominates the formation, expansion, shrinkage, and disappearance of the vortexes, and thus, it is the major factor of unstart coupling of multiple-modules hypersonic inlet. The coupling effect among multiple modules makes hypersonic inlet be more likely unstarted.

Unstart Coupling Mechanism Analysis of Multiple-Modules Hypersonic Inlet

PubMed Central

Wang, Lei; Cao, Shibin

2013-01-01

The combination of multiplemodules in parallel manner is an important way to achieve the much higher thrust of scramjet engine. For the multiple-modules scramjet engine, when inlet unstarted oscillatory flow appears in a single-module engine due to high backpressure, how to interact with each module by massflow spillage, and whether inlet unstart occurs in other modules are important issues. The unstarted flowfield and coupling characteristic for a three-module hypersonic inlet caused by center module II and side module III were, conducted respectively. The results indicate that the other two hypersonic inlets are forced into unstarted flow when unstarted phenomenon appears on a single-module hypersonic inlet due to high backpressure, and the reversed flow in the isolator dominates the formation, expansion, shrinkage, and disappearance of the vortexes, and thus, it is the major factor of unstart coupling of multiple-modules hypersonic inlet. The coupling effect among multiple modules makes hypersonic inlet be more likely unstarted. PMID:24348146

The negative effects of cadmium on Bermuda grass growth might be offset by submergence.

PubMed

Tan, Shuduan; Huang, Huang; Zhu, Mingyong; Zhang, Kerong; Xu, Huaqin; Wang, Zhi; Wu, Xiaoling; Zhang, Quanfa

2013-10-01

Revegetation in the water-level-fluctuation zone (WLFZ) could stabilize riverbanks, maintain local biodiversity, and improve reservoir water quality in the Three Gorges Reservoir Region (TGRR). However, submergence and cadmium (Cd) may seriously affect the survival of transplantations. Bermuda grass (Cynodon dactylon) is a stoloniferous and rhizomatous prostrate weed displaying high growth rate. A previous study has demonstrated that Bermuda grass can tolerate deep submergence and Cd stress, respectively. In the present study, we further analyzed physiological responses of Bermuda grass induced by Cd-and-submergence stress. The ultimate goal was to explore the possibility of using Bermuda grass for revegetation in the WLFZ of China's TGRR and other riparian areas. The Cd-and-submergence-treated plants had higher malondialdehyde contents and peroxidase than control, and both increased with the Cd concentration increase. All treated plants catalase activity increased with the experimental duration increases, and their superoxide dismutase also gradually increased with the Cd concentration from 1 day to 15 days. Total biomass of the same Cd-and-submergence plants increased along the experimental duration as well. Plants exposed to Cd-and-submergence stress showed shoot elongation. The heights of all treated plants were taller than those of the control. Leaf chlorophyll contents, maximum leaf length, and soluble sugars contents of all the Cd-and-submergence-treated plants were more than those of the untreated control. Although Cd inhibits plants growth, decreases chlorophyll and biomass content, and with the submergence induced the leaf and shoot elongation, more part of the Cd-and-submergence stress plants appeared in the air, exhibited fast growth with maintenance of leaf color, which guaranteed the plants' photosynthesis, and ensured the total biomass and carbohydrate sustainability, further promoting Cd-and-submergence tolerance. The results imply that the negative

Orders of magnitude: A history of the NACA and NASA, 1915-1990

NASA Technical Reports Server (NTRS)

Bilstein, Roger E.

1989-01-01

This edition brings up to date the history of U.S. agencies for space exploration, the NACA and NASA, from 1915 through 1990. Early aviation and aeronautics research are described, with particular emphasis on the impact of the two world wars on aeronautics development and the postwar exploitation of those technologies. The reorganization and expansion of the NACA into NASA is described in detail as well as NASA's relationship with industry, the university system, and international space agencies such as the ESA. The dramatic space race of the 1950 and 1960s is recounted through a detailed histroy of the Gemini and Apollo programs and followed by a discussion of the many valuable social/scientific application of aeronautics technologies, many of which were realized through the launching of successful satellite projects. The further solar system explorations of the Voyager missions are described, as it the Challenger tragedy and the 1988 return to space of the Shuttle program. Future plans are outlined for a cooperatively funded international space station to foster the ongoing study of space science.

Starting of generic inlet with blunted wedges

NASA Astrophysics Data System (ADS)

Borovoy, V.; Mosharov, V.; Radchenko, V.; Skuratov, A.; Struminskaya, I.

2017-06-01

Bluntness e¨ect of gas-compressing wedges on starting and §ow structure in an air inlet was investigated experimentally. The inlet was of internal compression type with §at walls and rectangular cross section. The experiments were carried out in the wind tunnel UT-1M at Mach numbers M = 5 and 8 and Reynolds numbers Re∞L from 2.8 · 106 to 23 · 106. The §ow characteristics were measured by panoramic optical methods. Data demonstrating in§uence of wedge bluntness radius on the inlet starting were obtained at di¨erent Mach and Reynolds numbers as well as at di¨erent contraction ratios. Ambiguity of the §ow regime in the inlet under certain conditions was found.

CFD study on NACA 4415 airfoil implementing spherical and sinusoidal Tubercle Leading Edge

PubMed Central

2017-01-01

The Humpback whale tubercles have been studied for more than a decade. Tubercle Leading Edge (TLE) effectively reduces the separation bubble size and helps in delaying stall. They are very effective in case of low Reynolds number flows. The current Computational Fluid Dynamics (CFD) study is on NACA 4415 airfoil, at a Reynolds number 120,000. Two TLE shapes are tested on NACA 4415 airfoil. The tubercle designs implemented on the airfoil are sinusoidal and spherical. A parametric study is also carried out considering three amplitudes (0.025c, 0.05c and 0.075c), the wavelength (0.25c) is fixed. Structured mesh is utilized to generate grid and Transition SST turbulence model is used to capture the flow physics. Results clearly show spherical tubercles outperform sinusoidal tubercles. Furthermore experimental study considering spherical TLE is carried out at Reynolds number 200,000. The experimental results show that spherical TLE improve performance compared to clean airfoil. PMID:28850622

CFD study on NACA 4415 airfoil implementing spherical and sinusoidal Tubercle Leading Edge.

PubMed

Aftab, S M A; Ahmad, K A

2017-01-01

The Humpback whale tubercles have been studied for more than a decade. Tubercle Leading Edge (TLE) effectively reduces the separation bubble size and helps in delaying stall. They are very effective in case of low Reynolds number flows. The current Computational Fluid Dynamics (CFD) study is on NACA 4415 airfoil, at a Reynolds number 120,000. Two TLE shapes are tested on NACA 4415 airfoil. The tubercle designs implemented on the airfoil are sinusoidal and spherical. A parametric study is also carried out considering three amplitudes (0.025c, 0.05c and 0.075c), the wavelength (0.25c) is fixed. Structured mesh is utilized to generate grid and Transition SST turbulence model is used to capture the flow physics. Results clearly show spherical tubercles outperform sinusoidal tubercles. Furthermore experimental study considering spherical TLE is carried out at Reynolds number 200,000. The experimental results show that spherical TLE improve performance compared to clean airfoil.

Na/Ca exchange in the basolateral membrane of the A6 cell monolayer: role in Cai homeostasis.

PubMed

Brochiero, E; Raschi, C; Ehrenfeld, J

1995-05-01

The presence of a Na/Ca exchanger in A6 cells was investigated by measuring intracellular calcium (Cai) fluctuations and the 45Ca fluxes through the basolateral membranes (blm) of the cell monolayer. Removal of Na+ from the medium produced a transient increase in Cai followed by a regulatory phase returning Cai to control levels in 3-4 min, this phase being greatly accelerated (< 60 s) by NaCl addition (apparent Km of approximately 5 mM Na+). The Cai increase was only found with the Na(+)-free medium on the basolateral side of the cell monolayer. A twofold increase in the 45Ca influx was observed under these conditions. In Ca(2+)- depleted cells, the initial Cai increase after Ca2+ addition to the medium was greater when the putative Na/Ca exchanger was not functioning (i.e. in a Na(+)-free medium). 45Ca effluxes through the blm of the monolayer were greatly and transiently increased by a Na(+)-free medium on the serosal side and blocked by orthovanadate (1 mM). The Cai increased induced by a hypo-osmotic shock was greater in cells bathed in a Na(+)-medium, conditions expected to block the activity of the Na/Ca exchanger. These findings support the hypothesis that a Na/Ca exchanger is present on the blm of A6 cells and affirm its role in Cai homeostasis in steady-state conditions and following osmotic shock. In addition, a Ca2+ pump also located on the blm and Ca2+ stores sensitive to inositol 1,4,5-trisphosphate were found to be implicated in Cai homeostasis.

CFD Models of a Serpentine Inlet, Fan, and Nozzle

NASA Technical Reports Server (NTRS)

Chima, R. V.; Arend, D. J.; Castner, R. S.; Slater, J. W.; Truax, P. P.

2010-01-01

Several computational fluid dynamics (CFD) codes were used to analyze the Versatile Integrated Inlet Propulsion Aerodynamics Rig (VIIPAR) located at NASA Glenn Research Center. The rig consists of a serpentine inlet, a rake assembly, inlet guide vanes, a 12-in. diameter tip-turbine driven fan stage, exit rakes or probes, and an exhaust nozzle with a translating centerbody. The analyses were done to develop computational capabilities for modeling inlet/fan interaction and to help interpret experimental data. Three-dimensional Reynolds averaged Navier-Stokes (RANS) calculations of the fan stage were used to predict the operating line of the stage, the effects of leakage from the turbine stream, and the effects of inlet guide vane (IGV) setting angle. Coupled axisymmetric calculations of a bellmouth, fan, and nozzle were used to develop techniques for coupling codes together and to investigate possible effects of the nozzle on the fan. RANS calculations of the serpentine inlet were coupled to Euler calculations of the fan to investigate the complete inlet/fan system. Computed wall static pressures along the inlet centerline agreed reasonably well with experimental data but computed total pressures at the aerodynamic interface plane (AIP) showed significant differences from the data. Inlet distortion was shown to reduce the fan corrected flow and pressure ratio, and was not completely eliminated by passage through the fan

The Study on the Durability of Submerged Structure Displacement due to Concrete Failure

NASA Astrophysics Data System (ADS)

Mohd, M.; Zainon, O.; Rasib, A. W.; Majid, Z.

2016-09-01

Concrete structures that exposed to marine environments are subjected to multiple deterioration mechanisms. An overview of the existing technology for submerged concrete, pressure resistant, concrete structures which related such as cracks, debonds, and delamination are discussed. Basic knowledge related to drowning durability such as submerged concrete structures in the maritime environment are the durability of a concrete and the ability to resist to weathering, chemical attack, abrasion or other deterioration processes. The measuring techniques and instrumentation for geometrical monitoring of submerged structural displacements have traditionally been categorized into two groups according to the two main groups, namely as geodetic surveying and geotechnical structural measurements of local displacements. This paper aims to study the durability of submerged concrete displacement and harmful effects of submerged concrete structures.

Examining Dynamic Stall for an Oscillating NACA 4412 Hydrofoil

NASA Astrophysics Data System (ADS)

McVay, Eric; Lang, Amy; Gamble, Lawren; Bradshaw, Michael

2013-11-01

Dynamic stall is unsteady separation that occurs when a hydrofoil pitches through the static stall angle while simultaneously experiencing a rapid change in angle of attack. The NACA 4412 hydrofoil was selected for this research because it has strong trailing edge turbulent boundary layer separation characteristics. General dynamic stall angle of attack for approximately symmetric airfoils has been recorded to occur at 24 degrees, with separation beginning at about 16 degrees. It is predicted that the boundary layer will stay attached at a higher angle of attack because of the cambered geometry of the hydrofoil. It is also hypothesized that the boundary layer separation occurs closer to the trailing edge and that the dynamic stall angle of attack occurs somewhere between 24 and 28 degrees for the oscillating NACA 4412 hydrofoil. This research was conducted in a water tunnel facility using Time Resolved Digital Particle Image Velocimetry (TR-DPIV). The hydrofoil was pitched up from 0 to 30 degrees at Reynolds numbers of 60,000, 80,000 and 100,000. Flow characteristics, dynamic stall angles of attack, and points of boundary layer separation were compared at each velocity with both tripped and un-tripped surfaces. Follow-on research will be conducted using flow control techniques from sharks and dolphins to examine the potential benefits of these natural designs for separation control. Support for this research by NSF REU Grant #1062611 and CBET Grant #0932352 is gratefully acknowledged.

NACA Apprentice is Trained on the Lab's Altitude Systems

NASA Image and Video Library

1955-02-21

An apprentice at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory shown training on the altitude supply air systems in the Engine Research Building. An ongoing four-year apprentice program was established at the laboratory in 1949 to facilitate the close interaction of the lab’s engineers, mechanics, technicians, and scientists. The apprentice school covered a variety of trades including aircraft mechanic, electronics instrumentation, machinist, and altitude systems mechanic, seen in this photograph. The apprentices rotated through the various shops and facilities to provide them with a well-rounded understanding of the work at the lab. The specialized skills required meant that NACA apprentices were held to a higher standard than those in industry. They had to pass written civil service exams before entering the program. Previous experience with mechanical model airplanes, radio transmission, six months of work experience, or one year of trade school was required. The Lewis program was certified by both the Department of Labor and the State of Ohio. One hundred fifty of the 2,000 hours of annual training were spent in the classroom. The remainder was devoted to study of models and hands-on work in the facilities. Examinations were coupled with evaluation by supervisors in the shops. The apprentices were promoted through a series of grades until they reached journeyman status. Those who excelled in the Apprentice Program would be considered for a separate five-year engineering draftsman program.

Wind-tunnel investigation of an N.A.C.A. 23012 airfoil with two arrangements of a wide-chord slotted flap

NASA Technical Reports Server (NTRS)

Harris, Thomas A

1939-01-01

An investigation has been made in the N.A.C.A. 7- by 10-foot wind tunnel of a large-chord N.A.C.A. 23012 airfoil with several arrangements of a 40-percent-chord slotted flap to determine the section aerodynamic characteristics of the airfoil as affected by slot shape, flap location, and flap deflection. The flap positions for maximum lift, the polar for arrangements considered favorable for take-off and climb, and the complete section aerodynamic characteristics for selected optimum arrangements were determined. A discussion is given of the relative merits of the various arrangements. A comparison is made of slotted flaps of different chords on the N.A.C.A. 23012 airfoil. The best 40-percent-chord slotted flap is only slightly superior to the 25-percent-chord slotted flap from considerations of maximum lift coefficient and low drag for take-off and initial climb.

Submerged plant’s ability to present photosynthesis based on oxygen production

NASA Astrophysics Data System (ADS)

Supriatno, B.; Ulfa, K.

2018-05-01

This study aims to provide information about alternative experimental photosynthesis for experimental teaching practices in school in the coastal region. The research method was conducted experimentally by taking examples of Submerged plant in littoral area of Leuweng Sancang beach, Garut. Plant samples were given the same light intensity treatment, then the oxygen productivity was studied as an indicator of photosynthesis rate. The results showed that there were different photosynthetic rates in different types of submerged plants. Algae as submerged plants generally photosynthesize at high light intensity. However, there are also plants with photosynthesis in low light. The comparison between sea grass (Thallasia sp) with sea weed (Ulva sp) shows the difference in oxygen productivity. Submerged plants based on their ability to produce measurable oxygen can be utilized for experiments on photosynthesis learning.

Effect of replacing surface inlets with blind or gravel inlets on sediment and phosphorus subsurface drainage losses

USDA-ARS?s Scientific Manuscript database

Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine whether modifying open inlets by burying them in gravel capped with 30 cm of sandy clay loam soil or in ve...

Detecting submerged bodies: controlled research using side-scan sonar to detect submerged proxy cadavers.

PubMed

Healy, Carrie A; Schultz, John J; Parker, Kenneth; Lowers, Bim

2015-05-01

Forensic investigators routinely deploy side-scan sonar for submerged body searches. This study adds to the limited body of literature by undertaking a controlled project to understand how variables affect detection of submerged bodies using side-scan sonar. Research consisted of two phases using small and medium-sized pig (Sus scrofa) carcasses as proxies for human bodies to investigate the effects of terrain, body size, frequency, swath width, and state of decomposition. Results demonstrated that a clear, flat, sandy pond floor terrain was optimal for detection of the target as irregular terrain and/or vegetation are major limitations that can obscure the target. A higher frequency towfish was preferred for small bodies, and a 20 m swath width allowed greater visibility and easier maneuverability of the boat in this environment. Also, the medium-sized carcasses were discernable throughout the 81-day study period, indicating that it is possible to detect bodies undergoing decomposition with side-scan sonar. © 2015 American Academy of Forensic Sciences.

Ethylene-promoted elongation: an adaptation to submergence stress.

PubMed

Jackson, Michael B

2008-01-01

A sizeable minority of taxa is successful in areas prone to submergence. Many such plants elongate with increased vigour when underwater. This helps to restore contact with the aerial environment by shortening the duration of inundation. Poorly adapted species are usually incapable of this underwater escape. Evidence implicating ethylene as the principal factor initiating fast underwater elongation by leaves or stems is evaluated comprehensively along with its interactions with other hormones and gases. These interactions make up a sequence of events that link the perception of submergence to a prompt acceleration of extension. The review encompasses whole plant physiology, cell biology and molecular genetics. It includes assessments of how submergence threatens plant life and of the extent to which the submergence escape demonstrably improves the likelihood of survival. Experimental testing over many years establishes ethylene-promoted underwater extension as one of the most convincing examples of hormone-mediated stress adaptation by plants. The research has utilized a wide range of species that includes numerous angiosperms, a fern and a liverwort. It has also benefited from detailed physiological and molecular studies of underwater elongation by rice (Oryza sativa) and the marsh dock (Rumex palustris). Despite complexities and interactions, the work reveals that the signal transduction pathway is initiated by the simple expediency of physical entrapment of ethylene within growing cells by a covering of water.

Off-Design Performance of a Streamline-Traced, External-Compression Supersonic Inlet

NASA Technical Reports Server (NTRS)

Slater, John W.

2017-01-01

A computational study was performed to explore the aerodynamic performance of a streamline-traced, external-compression inlet designed for Mach 1.664 at off-design conditions of freestream Mach number, angle-of-attack, and angle-of-sideslip. Serious degradation of the inlet performance occurred for negative angles-of-attack and angles-of-sideslip greater than 3 degrees. At low subsonic speeds, the swept leading edges of the inlet created a pair of vortices that propagated to the engine face. Increasing the bluntness of the cowl lip showed no real improvement in the inlet performance at the low speeds, but did improve the inlet performance at the design conditions. Reducing the inlet flow rate improved the inlet performance, but at the likely expense of reduced thrust of the propulsion system. Deforming the cowl lip for low-speed operation of the inlet increased the inlet capture area and improved the inlet performance.

Hydrodynamic Tests in the N.A.C.A. Tank of a Model of the Hull of the Short Calcutta Flying Boat

NASA Technical Reports Server (NTRS)

Ward, Kenneth E

1937-01-01

The hydrodynamic characteristics of a model of the hull of the Short Calcutta (N.A.C.A. Model 47) are presented in non-dimensional form. This model represents one of a series of hulls of successful foreign and domestic flying boats the characteristics of which are being obtained under similar test conditions in the N.A.C.A. tank. The take-off distance and time for a flying boat having the hull of the Calcutta are compared at two values of the gross load with the corresponding distances and times for the same flying boat having hulls of two representative American types, the Sikorsky S-40 and the N.A.C.A. 11-A. This comparison indicates that for hulls of the widely different forms compared, the differences in take-off time and distance are negligible.

Inlet Trade Study for a Low-Boom Aircraft Demonstrator

NASA Technical Reports Server (NTRS)

Heath, Christopher M.; Slater, John W.; Rallabhandi, Sriram K.

2016-01-01

Propulsion integration for low-boom supersonic aircraft requires careful inlet selection, placement, and tailoring to achieve acceptable propulsive and aerodynamic performance, without compromising vehicle sonic boom loudness levels. In this investigation, an inward-turning streamline-traced and axisymmetric spike inlet are designed and independently installed on a conceptual low-boom supersonic demonstrator aircraft. The airframe was pre-shaped to achieve a target ground under-track loudness of 76.4 PLdB at cruise using an adjoint-based design optimization process. Aircraft and inlet performance characteristics were obtained by solution of the steady-state Reynolds-averaged Navier-Stokes equations. Isolated cruise inlet performance including total pressure recovery and distortion were computed and compared against installed inlet performance metrics. Evaluation of vehicle near-field pressure signatures, along with under- and off-track propagated loudness levels is also reported. Results indicate the integrated axisymmetric spike design offers higher inlet pressure recovery, lower fan distortion, and reduced sonic boom. The vehicle with streamline-traced inlet exhibits lower external wave drag, which translates to a higher lift-to-drag ratio and increased range capability.

Impacts of climate change on submerged and emergent wetland plants

Treesearch

Frederick T. Short; Sarian Kosten; Pamela A. Morgan; Sparkle L Malone; Gregg E. Moore

2016-01-01

Submerged and emergent wetland plant communities are evaluated for their response to global climate change (GCC), focusing on seagrasses, submerged freshwater plants, tidal marsh plants, freshwater marsh plants and mangroves. Similarities and differences are assessed in plant community responses to temperature increase, CO2increase, greater UV-B exposure, sea...

Oxygen absorption by adventitious roots promotes the survival of completely submerged terrestrial plants

PubMed Central

Ayi, Qiaoli; Zeng, Bo; Liu, Jianhui; Li, Siqi; van Bodegom, Peter M.; Cornelissen, Johannes H. C.

2016-01-01

Background and Aims Flooding imposes stress upon terrestrial plants because it results in oxygen deficiency, which is considered a major problem for submerged plants. A common response of terrestrial plants to flooding is the formation of aquatic adventitious roots. Some studies have shown that adventitious roots on submerged plants are capable of absorbing water and nutrients. However, there is no experimental evidence for the possible oxygen uptake function of adventitious roots or for how important this function might be for the survival of plants during prolonged submergence. This study aims to investigate whether adventitious roots absorb oxygen from the water column, and whether this new function is beneficial to the survival of completely submerged plants. Methods Taking Alternanthera philoxeroides (Mart.) Griseb. as a representative species, the profiling of the underwater oxygen gradient towards living and dead adventitious roots on completely submerged plants was conducted, the oxygen concentration in stem nodes with and without adventitious roots was measured, and the growth, survival and non-structural carbohydrate content of completely submerged plants with and without adventitious roots was investigated. Key Results Oxygen profiles in the water column of adventitious roots showed that adventitious roots absorbed oxygen from water. It is found that the oxygen concentration in stem nodes having adventitious roots was higher than that in stem nodes without adventitious roots, which implies that the oxygen absorbed by adventitious roots from water was subsequently transported from the roots to other plant tissues. Compared with plants whose adventitious roots had been pruned, those with intact adventitious roots had slower leaf shedding, slower plant mass reduction, more efficient carbohydrate economy and prolonged survival when completely submerged. Conclusions The adventitious roots of A. philoxeroides formed upon submergence can absorb oxygen from

Force Characteristics in the Submerged and Planing Condition of a 1/5.78-Scale Model of a Hydro-Ski-Wheel Combination for the Grumman JRF-5 Airplane. TED No. NACA DE 357

NASA Technical Reports Server (NTRS)

Land, Norman S.; Pelz, Charles A.

1952-01-01

Force characteristics determined from tank tests of a 1/5.78 scale model of a hydro-ski-wheel combination for the Grumman JRF-5 airplane are presented. The model was tested in both the submerged and planing conditions over a range of trim, speed, and load sufficiently large to represent the most probable full-size conditions.

Demonstration and Field Evaluation of Streambank Stabilization with Submerged Vanes

USGS Publications Warehouse

Whitman, H.; Hoopes, J.; Poggi, D.; Fitzpatrick, F.; Walz, K.; ,

2001-01-01

The effectiveness of submerged vanes for reducing bank erosion and improving aquatic habitat is being evaluated at a site on North Fish Creek, a Lake Superior tributary. Increased runoff from agricultural areas with clayey soils has increased flood magnitudes and the erosion potential/transport capacity of the stream. Most of the creek's sediment load originates from the erosion of 17 large bluffs. This creek contains important recreational fisheries that are potentially limited by the loss of aquatic habitat from deposition of sediment on spawning beds. Submerged vanes are a cost effective and environmentally less intrusive alternative to traditional structural stabilization measures. Submerged vanes protrude from a channel bed, are oriented at an angle to the local velocity, and are distributed along a portion of channel. They induce a transverse force and torque on the flow along with longitudinal vortexes that alter the cross sectional shape and alignment of the channel. Submerged vanes were installed at a bluff/bend site in summer and fall 2000. The number, size, and layout of the vanes were based upon the channel morphology under estimated bankfull conditions. The effectiveness of the vanes will be evaluated by comparing surveys of the bluff face, streamflow, and channel conditions for several years after installation of the submerged vanes with surveys before and immediately after their installation.

33 CFR 80.505 - Cape Henlopen, DE to Cape Charles, VA.

Code of Federal Regulations, 2010 CFR

2010-07-01

... to Cape Charles, VA. (a) A line drawn from the seaward extremity of Indian River Inlet North Jetty to Indian River Inlet South Jetty Light. (b) A line drawn from Ocean City Inlet Light 6, 225° true across Ocean City Inlet to the submerged south breakwater. (c) A line drawn from Assateague Beach Tower Light...

Miniature piezo electric vacuum inlet valve

DOEpatents

Keville, Robert F.; Dietrich, Daniel D.

1998-03-24

A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability. The low power (<1.6 watts), high pulse rate (<2 milliseconds), variable flow inlet valve is utilized for mass spectroscopic applications or other applications where pulsed or continuous flow conditions are needed. The inlet valve also has a very minimal dead volume of less than 0.01 std/cc. The valve can utilize, for example, a 12 Vdc input/750 Vdc, 3 mA output power supply compared to conventional piezo electric valves which require preloading of the crystal drive mechanism and 120 Vac, thus the valve of the present invention is smaller by a factor of three.

Experimental and calculated characteristics of three wings of NACA 64-210 and 65-210 airfoil sections with and without 2 degree washout

NASA Technical Reports Server (NTRS)

Sivells, James C

1947-01-01

Report presents the results of an investigation conducted to determine some of the effects of airfoil section and washout on the experimental and calculated characteristics of 10-percent-thick wings. Three wings of aspect ratio 9 and ratio of root chord to tip chord 2.5 were tested. One wing had NACA 64-210 sections and 2 degree washout, the second had NACA 65-210 sections and 2 degree washout, and the third had NACA 65-210 sections and 0 degree washout. It was found that the experimental characteristics of the wings could be satisfactorily predicted from calculations based upon two-dimensional data when the airfoil contours of the wings conformed to the true airfoil sections with the same high degree of accuracy as the two-dimensional models.

Methodology for the Design of Streamline-Traced External-Compression Supersonic Inlets

NASA Technical Reports Server (NTRS)

Slater, John W.

2014-01-01

A design methodology based on streamline-tracing is discussed for the design of external-compression, supersonic inlets for flight below Mach 2.0. The methodology establishes a supersonic compression surface and capture cross-section by tracing streamlines through an axisymmetric Busemann flowfield. The compression system of shock and Mach waves is altered through modifications to the leading edge and shoulder of the compression surface. An external terminal shock is established to create subsonic flow which is diffused in the subsonic diffuser. The design methodology was implemented into the SUPIN inlet design tool. SUPIN uses specified design factors to design the inlets and computes the inlet performance, which includes the flow rates, total pressure recovery, and wave drag. A design study was conducted using SUPIN and the Wind-US computational fluid dynamics code to design and analyze the properties of two streamline-traced, external-compression (STEX) supersonic inlets for Mach 1.6 freestream conditions. The STEX inlets were compared to axisymmetric pitot, two-dimensional, and axisymmetric spike inlets. The STEX inlets had slightly lower total pressure recovery and higher levels of total pressure distortion than the axisymmetric spike inlet. The cowl wave drag coefficients of the STEX inlets were 20% of those for the axisymmetric spike inlet. The STEX inlets had external sound pressures that were 37% of those of the axisymmetric spike inlet, which may result in lower adverse sonic boom characteristics. The flexibility of the shape of the capture cross-section may result in benefits for the integration of STEX inlets with aircraft.

Computational Analysis of a Low-Boom Supersonic Inlet

NASA Technical Reports Server (NTRS)

Chima, Rodrick V.

2011-01-01

A low-boom supersonic inlet was designed for use on a conceptual small supersonic aircraft that would cruise with an over-wing Mach number of 1.7. The inlet was designed to minimize external overpressures, and used a novel bypass duct to divert the highest shock losses around the engine. The Wind-US CFD code was used to predict the effects of capture ratio, struts, bypass design, and angles of attack on inlet performance. The inlet was tested in the 8-ft by 6-ft Supersonic Wind Tunnel at NASA Glenn Research Center. Test results showed that the inlet had excellent performance, with capture ratios near one, a peak core total pressure recovery of 96 percent, and a stable operating range much larger than that of an engine. Predictions generally compared very well with the experimental data, and were used to help interpret some of the experimental results.

Tuned intake air inlet for a rotary engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corbett, W.D.; Sheaffer, B.L.

This patent describes, in a rotary internal combustion engine, an improved assembly for providing a balanced flow of combustion air to the fuel supply inlet. It comprises: a plenum chamber attached to the engine block, the plenum chamber including an air inlet adapted to receive air from the cooling air exit passage and an air outlet for the discharge of air; and an outlet conduit connecting the air outlet and the fuel supply inlet. The conduit disposed to partially surround the plenum chamber to provide a conduit length substantially greater than the distance from the cooling air exit passage totmore » he fuel supply inlet.« less

Investigation of Inlet Control Parameters for an External-internal-compression Inlet from Mach 2.1 to 3.0

NASA Technical Reports Server (NTRS)

Anderson, B. H.; Bowditch, D. N.

1958-01-01

Investigation of the control parameters of an external-internal compression inlet indicates that the cowl-lip shock provides a signal to position the spike and to start the inlet over a Mach number range from 2.1 to 3.0. Use of a single fixed probe position to control the spike over the range of conditions resulted in a 3.7-count loss in total-pressure recovery at Mach 3.0 and 0 deg angle of attack. Three separate shock-sensing-probe positions were required to set the spike for peak recovery from Mach 2.1 to 3.0 and angles of attack from 0 deg to 6 deg. When the inlet was unstarted, an erroneous signal was obtained from the normal-shock control through most of the starting cycle that prevented the inlet from starting. Therefore, it was necessary to over-ride the normal-shock control signal and not allow the control to position the terminal shock until the spike was positioned.

Hydraulic Performance of Set-Back Curb Inlets

DOT National Transportation Integrated Search

1998-06-01

The objective of this study was to develop hydraulic design charts for the location and sizing of set-back curb inlets. An extensive program of hydraulic model testing was conducted to evaluate the performance of various inlet opening sizes. The grad...

Production and processing of Metarhizium anisopliae var. acridum submerged conidia for locust and grasshopper control.

PubMed

Kassa, Adane; Stephan, Dietrich; Vidal, Stefan; Zimmermann, Gisbert

2004-01-01

Currently, mycopesticide development for locust and grasshopper control depends on aerial conidia or submerged spores of entomopathogenic fungi. In our study, the production of submerged conidia of Metarhizium anisopliae var. acridum (IMI 330189) was investigated in a liquid medium containing 3% biomalt and 1% yeast extract (BH-medium). The effects of freeze and spray drying techniques on the quality of submerged conidia were determined. The influence of different additives on the viability of fresh submerged conidia and their suitability for oil flowable concentrate formulation development was assessed. In a BH medium maintained at 180 rev min(-1), at 30 degrees C for 72 h, IMI 330189 produced a green pigmented biomass of submerged conidia whereas in Adámek medium it produced a yellowish biomass of submerged spores. The spore concentration was high in both media; however, the size of the spores produced in the BH medium was significantly lower than those produced in Adámek medium (P < 0.001). Submerged conidia can be effectively dried using either freeze or spray drying techniques. The viability and speed of germination were significantly affected by the drying and pulverizing process (P < 0.001). The initial viability was significantly higher for spray-dried submerged conidia than for freeze-dried spores. Pulverizing of freeze-dried submerged conidia reduced the speed of germination and the viability by 63-95%. Dried submerged conidia can be stored over 45 wk at low temperatures (< 10 degrees) without suffering a significant loss in viability. Furthermore, we have identified carriers that are suitable for oil flowable concentrate formulation development.

Photographer; NACA North American F-100A NASA-200 Super Sabre airplane - wing leading edge deflected

NASA Technical Reports Server (NTRS)

1958-01-01

Photographer; NACA North American F-100A NASA-200 Super Sabre airplane - wing leading edge deflected 60 degrees for increased lift with boundary=layer control; takeoff preformance was improved 10% (mar 1960)

Republic P-47G Thunderbolt and the NACA Flight Operations Crew

NASA Image and Video Library

1944-03-21

The Flight Operations crew stands before a Republic P-47G Thunderbolt at the National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory in Cleveland, Ohio. The laboratory’s Flight Research Section was responsible for conducting a variety of research flights. During World War II most of the test flights complemented the efforts in ground-based facilities to improve engine cooling systems or study advanced fuel mixtures. The Republic P–47G was loaned to the laboratory to test NACA modifications to the Wright R–2800 engine’s cooling system at higher altitudes. The laboratory has always maintained a fleet of aircraft so different research projects were often conducted concurrently. The flight research program requires an entire section of personnel to accomplish its work. This staff generally consists of a flight operations group, which includes the section chief, pilots and administrative staff; a flight maintenance group with technicians and mechanics responsible for inspecting aircraft, performing checkouts and installing and removing flight instruments; and a flight research group that integrates the researchers’ experiments into the aircraft. The staff at the time of this March 1944 photograph included 3 pilots, 16 planning and analysis engineers, 36 mechanics and technicians, 10 instrumentation specialists, 6 secretaries and 5 computers.

Generic Hypersonic Inlet Module Analysis

NASA Technical Reports Server (NTRS)

Cockrell, Chares E., Jr.; Huebner, Lawrence D.

2004-01-01

A computational study associated with an internal inlet drag analysis was performed for a generic hypersonic inlet module. The purpose of this study was to determine the feasibility of computing the internal drag force for a generic scramjet engine module using computational methods. The computational study consisted of obtaining two-dimensional (2D) and three-dimensional (3D) computational fluid dynamics (CFD) solutions using the Euler and parabolized Navier-Stokes (PNS) equations. The solution accuracy was assessed by comparisons with experimental pitot pressure data. The CFD analysis indicates that the 3D PNS solutions show the best agreement with experimental pitot pressure data. The internal inlet drag analysis consisted of obtaining drag force predictions based on experimental data and 3D CFD solutions. A comparative assessment of each of the drag prediction methods is made and the sensitivity of CFD drag values to computational procedures is documented. The analysis indicates that the CFD drag predictions are highly sensitive to the computational procedure used.

30 CFR 77.303 - Hot gas inlet chamber dropout doors.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet chamber...

30 CFR 77.303 - Hot gas inlet chamber dropout doors.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet chamber...

30 CFR 77.303 - Hot gas inlet chamber dropout doors.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet chamber...

30 CFR 77.303 - Hot gas inlet chamber dropout doors.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet chamber...

Miniature piezo electric vacuum inlet valve

DOEpatents

Keville, R.F.; Dietrich, D.D.

1998-03-24

A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability is disclosed. The low power (<1.6 watts), high pulse rate (<2 milliseconds), variable flow inlet valve is utilized for mass spectroscopic applications or other applications where pulsed or continuous flow conditions are needed. The inlet valve also has a very minimal dead volume of less than 0.01 std/cc. The valve can utilize, for example, a 12 Vdc input/750 Vdc, 3 mA output power supply compared to conventional piezo electric valves which require preloading of the crystal drive mechanism and 120 Vac, thus the valve of the present invention is smaller by a factor of three. 6 figs.

Effect of Blowing on Boundary Layer of Scarf Inlet

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.; Clark, Lorenzo R.

2004-01-01

When aircraft operate in stationary or low speed conditions, airflow into the engine accelerates around the inlet lip and pockets of turbulence that cause noise and vibration can be ingested. This problem has been encountered with engines equipped with the scarf inlet, both in full scale and in model tests, where the noise produced during the static test makes it difficult to assess the noise reduction performance of the scarf inlet. NASA Langley researchers have implemented boundary layer control in an attempt to reduce the influence of the flow nonuniformity in a 12-in. diameter model of a high bypass fan engine mounted in an anechoic chamber. Static pressures and boundary layer profiles were measured in the inlet and far field acoustic measurements were made to assess the effectiveness of the blowing treatment. The blowing system was found to lack the authority to overcome the inlet distortions. Methods to improve the implementation of boundary layer control to reduce inlet distortion are discussed.

Cavitation Characteristics of a NACA 63-424 Hydrofoil and Performance Comparison with a Bidirectional Version of the Foil

NASA Astrophysics Data System (ADS)

Nedyalkov, Ivaylo; Wosnik, Martin

2012-11-01

A NACA 63-424 hydrofoil with a 75 mm chord and a 152 mm span was tested in the recently renovated 6-inch high-speed water tunnel at the University of New Hampshire. The NACA 63-424 foil is being considered for use on rotors of marine hydrokinetic turbines, including the US Department of Energy Reference Horizontal Axis Turbine (RHAT) for tidal and ocean current applications. For various angles of attack, the foil was tested at speeds ranging from 2 m/s to 12 m/s. Pressure in the test section was varied independently. For each angle, speed and pressure setting, high speed videos were recorded (at 3600 frames per second and above). Cavitation inception and desinance were obtained. Lift and drag were measured using a new 2-component force balance. In tidal turbines applications, bidirectional foils do not require pitch control, hence the experiments were repeated for a bidirectional version of the NACA 63-424 foil and the characteristics of the two foils were compared. The results can be used to predict cavitation inception and performance of marine hydrokinetic turbines, for a given site, deployment depth and and tip speed ratio.

Experimental Investigation of a Large-Scale Low-Boom Inlet Concept

NASA Technical Reports Server (NTRS)

Hirt, Stefanie M.; Chima, Rodrick V.; Vyas, Manan A.; Wayman, Thomas R.; Conners, Timothy R.; Reger, Robert W.

2011-01-01

A large-scale low-boom inlet concept was tested in the NASA Glenn Research Center 8- x 6- foot Supersonic Wind Tunnel. The purpose of this test was to assess inlet performance, stability and operability at various Mach numbers and angles of attack. During this effort, two models were tested: a dual stream inlet designed to mimic potential aircraft flight hardware integrating a high-flow bypass stream; and a single stream inlet designed to study a configuration with a zero-degree external cowl angle and to permit surface visualization of the vortex generator flow on the internal centerbody surface. During the course of the test, the low-boom inlet concept was demonstrated to have high recovery, excellent buzz margin, and high operability. This paper will provide an overview of the setup, show a brief comparison of the dual stream and single stream inlet results, and examine the dual stream inlet characteristics.

Three dimensional viscous analysis of a hypersonic inlet

NASA Technical Reports Server (NTRS)

Reddy, D. R.; Smith, G. E.; Liou, M.-F.; Benson, Thomas J.

1989-01-01

The flow fields in supersonic/hypersonic inlets are currently being studied at NASA Lewis Research Center using 2- and 3-D full Navier-Stokes and Parabolized Navier-Stokes solvers. These tools have been used to analyze the flow through the McDonnell Douglas Option 2 inlet which has been tested at Calspan in support of the National Aerospace Plane Program. Comparisons between the computational and experimental results are presented. These comparisons lead to better overall understanding of the complex flows present in this class of inlets. The aspects of the flow field emphasized in this work are the 3-D effects, the transition from laminar to turbulent flow, and the strong nonuniformities generated within the inlet.

7. View north at back (canal side) of culvert inlet, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. View north at back (canal side) of culvert inlet, with canal bank completely removed. Background to foreground: back of inlet headwall with tops of high inlet barrels exposed; vertical transition wall between high inlet barrels and low, interior, inlet barrels; tops of low interior barrels; vertical heartening planks and low cutoff wall at site of former canal edge of canal bank; dewatered canal bed and plank sheathing on top of culvert barrels beneath canal bed. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

49 CFR 178.337-8 - Openings, inlets, and outlets.

Code of Federal Regulations, 2011 CFR

2011-10-01

... used to transport chlorine. The requirements for inlets and outlets on chlorine cargo tanks are in... dioxide, helium, krypton, neon, nitrogen, and xenon, or mixtures thereof. (6) In addition to the internal... equalization of pressure. (b) Inlets and discharge outlets on chlorine tanks. The inlet and discharge outlets...

49 CFR 178.337-8 - Openings, inlets, and outlets.

Code of Federal Regulations, 2010 CFR

2010-10-01

... used to transport chlorine. The requirements for inlets and outlets on chlorine cargo tanks are in... dioxide, helium, krypton, neon, nitrogen, and xenon, or mixtures thereof. (6) In addition to the internal... equalization of pressure. (b) Inlets and discharge outlets on chlorine tanks. The inlet and discharge outlets...

Submerged passively-safe power plant

DOEpatents

Herring, J. Stephen

1993-01-01

The invention as presented consists of a submerged passively-safe power station including a pressurized water reactor capable of generating at least 600 MW of electricity, encased in a double hull vessel, and provides fresh water by using the spent thermal energy in a multistage flash desalination process.

Short-term complete submergence of rice at the tillering stage increases yield.

PubMed

Zhang, Yajie; Wang, Zhensheng; Li, Lei; Zhou, Qun; Xiao, Yao; Wei, Xing; Zhou, Mingyao

2015-01-01

Flooding is a major threat to agricultural production. Most studies have focused on the lower water storage limit in rice fields, whereas few studies have examined the upper water storage limit. This study aimed to explore the effect of waterlogging at the rice tillering stage on rice growth and yield. The early-ripening late japonica variety Yangjing 4227 was selected for this study. The treatments included different submergence depths (submergence depth/plant height: 1/2 (waist submergence), 2/3 (neck submergence), and 1/1 (complete submergence)) and durations (1, 3, and 5 d). The control group was treated with the conventional alternation of drying and wetting. The effects of waterlogging at the tillering stage on root characteristics, dry matter production, nitrogen and phosphorus accumulation, yield, yield components, and 1-aminocyclopropane-1-carboxylic acid synthase (ACS) gene expression were explored. Compared with the control group, the 1/1 group showed significant increases in yield, seed-setting rate, photosynthetically efficient leaf area, and OS-ACS3 gene expression after 1 d of submergence. The grain number per panicle, dry weight of the aboveground and belowground parts, and number of adventitious roots also increased. Correlation analysis revealed a significant positive correlation between the panicle number and nitrogen content; however, no significant correlation was found for phosphorus content. If a decrease in rice yield of less than 10% is acceptable, half, 2/3, and complete submergence of the plants can be performed at the tillering stage for 1-3 d; this treatment will increase the space available for rice field water management/control and will improve rainfall resource utilization.

Noise radiation directivity from a wind-tunnel inlet with inlet vanes and duct wall linings

NASA Technical Reports Server (NTRS)

Soderman, P. T.; Phillips, J. D.

1986-01-01

The acoustic radiation patterns from a 1/15th scale model of the Ames 80- by 120-Ft Wind Tunnel test section and inlet have been measured with a noise source installed in the test section. Data were acquired without airflow in the duct. Sound-absorbent inlet vanes oriented parallel to each other, or splayed with a variable incidence relative to the duct long axis, were evaluated along with duct wall linings. Results show that splayed vans tend to spread the sound to greater angles than those measured with the open inlet. Parallel vanes narrowed the high-frequency radiation pattern. Duct wall linings had a strong effect on acoustic directivity by attenuating wall reflections. Vane insertion loss was measured. Directivity results are compared with existing data from square ducts. Two prediction methods for duct radiation directivity are described: one is an empirical method based on the test data, and the other is a analytical method based on ray acoustics.

A comparative analysis between NACA 4412 airfoil and it's modified form with tubercles

NASA Astrophysics Data System (ADS)

Hasan, Md. Jonayed; Islam, Md. Tazul; Hassan, Md. Mehedi

2017-06-01

The effect of tubercles on the leading edge of an airfoil become more vivid at high angle of attacks. The effect of tubercles with large wavelength and small amplitude on the leading edge of a NACA 4412 airfoil section was investigated numerically and experimentally. The phenomena of improving the airfoil performance by modifying the contours drove our interest to do this analysis. The models were developed & numerical simulations were carried out with both NACA 4412 airfoil and modified airfoil model at Re=1.03×106 and angles of attack ranging from 0° to 20°. Flow separation was analyzed with vector profiles. CL, CD at different angle of attacks was developed and it gave down noticeable pre-stall & post-stall behavior. The airfoils were studied experimentally in a low speed wind tunnel. Pressure distribution over the two airfoils was obtained. It was evident from the pressure distributions that the modified airfoil exhibits significant aerodynamic performance at high angles of attack. We can infer that these effects will be advantageous for maneuverability and post-stall behavior.

A Numerical Study of Hypersonic Forebody/Inlet Integration Problem

NASA Technical Reports Server (NTRS)

Kumar, Ajay

1991-01-01

A numerical study of hypersonic forebody/inlet integration problem is presented in the form of the view-graphs. The following topics are covered: physical/chemical modeling; solution procedure; flow conditions; mass flow rate at inlet face; heating and skin friction loads; 3-D forebogy/inlet integration model; and sensitivity studies.

A new approach for the design of hypersonic scramjet inlets

NASA Astrophysics Data System (ADS)

Raj, N. Om Prakash; Venkatasubbaiah, K.

2012-08-01

A new methodology has been developed for the design of hypersonic scramjet inlets using gas dynamic relations. The approach aims to find the optimal inlet geometry which has maximum total pressure recovery at a prescribed design free stream Mach number. The design criteria for inlet is chosen as shock-on-lip condition which ensures maximum capture area and minimum intake length. Designed inlet geometries are simulated using computational fluid dynamics analysis. The effects of 1D, 2D inviscid and viscous effects on performance of scramjet inlet are reported here. A correction factor in inviscid design is reported for viscous effects to obtain shock-on-lip condition. A parametric study is carried out for the effect of Mach number at the beginning of isolator for the design of scramjet inlets. Present results show that 2D and viscous effects are significant on performance of scramjet inlet. Present simulation results are matching very well with the experimental results available from the literature.

Experimental Investigation of Water Droplet Impingement on Airfoils, Finite Wings, and an S-duct Engine Inlet

NASA Technical Reports Server (NTRS)

Papadakis, Michael; Hung, Kuohsing E.; Vu, Giao T.; Yeong, Hsiung Wei; Bidwell, Colin S.; Breer, Martin D.; Bencic, Timothy J.

2002-01-01

Validation of trajectory computer codes, for icing analysis, requires experimental water droplet impingement data for a wide range of aircraft geometries as well as flow and icing conditions. This report presents improved experimental and data reduction methods for obtaining water droplet impingement data and provides a comprehensive water droplet impingement database for a range of test geometries including an MS(1)-0317 airfoil, a GLC-305 airfoil, an NACA 65(sub 2)-415 airfoil, a commercial transport tail section, a 36-inch chord natural laminar flow NLF(1)-0414 airfoil, a 48-inch NLF(1)-0414 section with a 25 percent chord simple flap, a state-of-the-art three-element high lift system, a NACA 64A008 finite span swept business jet tail, a full-scale business jet horizontal tail section, a 25 percent-scale business jet empennage, and an S-duct turboprop engine inlet. The experimental results were obtained at the NASA Glenn Icing Research Tunnel (IRT) for spray clouds with median volumetric diameter (MVD) of 11, 11.5, 21, 92, and 94 microns and for a range of angles of attack. The majority of the impingement experiments were conducted at an air speed of 175 mph corresponding to a Reynolds number of approximately 1.6 million per foot. The maximum difference of repeated tests from the average ranged from 0.24 to 12 percent for most of the experimental results presented. This represents a significant improvement in test repeatability compared to previous experimental studies. The increase in test repeatability was attributed to improvements made to the experimental and data reduction methods. Computations performed with the LEWICE-2D and LEWICE-3D computer codes for all test configurations are presented in this report. For the test cases involving median volumetric diameters of 11 and 21 microns, the correlation between the analytical and experimental impingement efficiency distributions was good. For the median volumetric diameters of 92 and 94-micron cases, however

Hydraulic efficiency of grate and curb-opening inlets under clogging effect.

DOT National Transportation Integrated Search

2012-04-01

The goal of this project is to investigate the hydraulic efficiencies of Type 13 (bar inlets), Type 16 : (vane inlets), and Type R (curb-opening inlets) for street and roadway drainage. Although these inlets : have been widely used in many metropolit...

Flow Simulation of Supersonic Inlet with Bypass Annular Duct

NASA Technical Reports Server (NTRS)

Kim, HyoungJin; Kumano, Takayasu; Liou, Meng-Sing; Povinelli, Louis A.; Conners, Timothy R.

2011-01-01

A relaxed isentropic compression supersonic inlet is a new concept that produces smaller cowl drag than a conventional inlet, but incurs lower total pressure recovery and increased flow distortion in the (radially) outer flowpath. A supersonic inlet comprising a bypass annulus to the relaxed isentropic compression inlet dumps out airflow of low quality through the bypass duct. A reliable computational fluid dynamics solution can provide considerable useful information to ascertain quantitatively relative merits of the concept, and further provide a basis for optimizing the design. For a fast and reliable performance evaluation of the inlet performance, an equivalent axisymmetric model whose area changes accounts for geometric and physical (blockage) effects resulting from the original complex three-dimensional configuration is proposed. In addition, full three-dimensional calculations are conducted for studying flow phenomena and verifying the validity of the equivalent model. The inlet-engine coupling is carried out by embedding numerical propulsion system simulation engine data into the flow solver for interactive boundary conditions at the engine fan face and exhaust plane. It was found that the blockage resulting from complex three-dimensional geometries in the bypass duct causes significant degradation of inlet performance by pushing the terminal normal shock upstream.

Computational Investigations of a NACA 0012 Airfoil in Low Reynolds Number Flows

DTIC Science & Technology

1992-09-01

11 D . RESULTS .................................... 13 1. Eppler E585 Airfoil ............................. 13 2. NACA 0012 Airfoil ...function in FORTRAN should also be used to calculate/3. D. RESULTS 1. Eppler E585 Airfoil The first investigation was conducted for an Eppler E585...The velocities match the given distribution well except for slight deviations at the trailing edge. This Figure 2.3 Eppler E585 Airfoil difference can

Submerged passively-safe power plant

DOEpatents

Herring, J.S.

1993-09-21

The invention as presented consists of a submerged passively-safe power station including a pressurized water reactor capable of generating at least 600 MW of electricity, encased in a double hull vessel, and provides fresh water by using the spent thermal energy in a multistage flash desalination process. 8 figures.

Enhanced Performance of Streamline-Traced External-Compression Supersonic Inlets

NASA Technical Reports Server (NTRS)

Slater, John W.

2015-01-01

A computational design study was conducted to enhance the aerodynamic performance of streamline-traced, external-compression inlets for Mach 1.6. Compared to traditional external-compression, two-dimensional and axisymmetric inlets, streamline-traced inlets promise reduced cowl wave drag and sonic boom, but at the expense of reduced total pressure recovery and increased total pressure distortion. The current study explored a new parent flowfield for the streamline tracing and several variations of inlet design factors, including the axial displacement and angle of the subsonic cowl lip, the vertical placement of the engine axis, and the use of porous bleed in the subsonic diffuser. The performance was enhanced over that of an earlier streamline-traced inlet such as to increase the total pressure recovery and reduce total pressure distortion.

Computational effects of inlet representation on powered hypersonic, airbreathing models

NASA Technical Reports Server (NTRS)

Huebner, Lawrence D.; Tatum, Kenneth E.

1993-01-01

Computational results are presented to illustrate the powered aftbody effects of representing the scramjet inlet on a generic hypersonic vehicle with a fairing, to divert the external flow, as compared to an operating flow-through scramjet inlet. This study is pertinent to the ground testing of hypersonic, airbreathing models employing scramjet exhaust flow simulation in typical small-scale hypersonic wind tunnels. The comparison of aftbody effects due to inlet representation is well-suited for computational study, since small model size typically precludes the ability to ingest flow into the inlet and perform exhaust simulation at the same time. Two-dimensional analysis indicates that, although flowfield differences exist for the two types of inlet representations, little, if any, difference in surface aftbody characteristics is caused by fairing over the inlet.

Sediment distribution and coastal processes in Cook Inlet, Alaska

NASA Technical Reports Server (NTRS)

Anderson, D. M.; Gatto, L. W.; Mckim, H. L.; Petrone, A.

1973-01-01

Regional hydrologic and oceanographic relationships in Cook Inlet, Alaska have been recognized from sequential ERTS-1 MSS imagery. Current patterns are visible in the inlet because of differential concentrations of suspended sediment. The circulation patterns within Cook Inlet are controlled primarily by the interaction between the semi-diurnal tides and the counter clockwise Alaska current. In general, heavily sediment laden water is seen to be confined to portions of the inlet north of the Forelands and west of Kalgin Island. Tongues of clear oceanic water are observed to enter the inlet through Kennedy Channel along the east shoreline in the vicinity of Cape Elizabeth. A recurring counterclockwise circulation pattern observed around Kalgin Island seems to result from the interplay of the northerly moving water along the east shore and the southerly moving, sediment laden, water along the west side of the inlet. Prominent, fresh water plumes, heavily laden with sediment are visible at the mouths of all major rivers. Relect plumes from as many as three tidal stages have been recognized.

Top-mounted inlet system feasibility for transonic-supersonic fighter aircraft. [V/STOL aircraft

NASA Technical Reports Server (NTRS)

Williams, T. L.; Hunt, B. L.; Smeltzer, D. B.; Nelms, W. P.

1981-01-01

The more salient findings are presented of recent top inlet performance evaluations aimed at assessing the feasibility of top-mounted inlet systems for transonic-supersonic fighter aircraft applications. Top inlet flow field and engine-inlet performance test data show the influence of key aircraft configuration variables-inlet longitudinal position, wing leading-edge extension planform area, canopy-dorsal integration, and variable incidence canards-on top inlet performance over the Mach range of 0.6 to 2.0. Top inlet performance data are compared with those or more conventional inlet/airframe integrations in an effort to assess the viability of top-mounted inlet systems relative to conventional inlet installations.

Fairchild C-82 Packet Destroyed in NACA Crash Fire Tests

NASA Image and Video Library

1952-09-21

A Fairchild C-82 Packet is purposely destroyed by researchers at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. In response to an escalating number of transport aircraft crashes in the mid-1940s, the NACA researchers undertook a decade-long investigation into a number of issues surrounding low-altitude aircraft crashes. The tests were conducted at the Ravenna Arsenal, approximately 60 miles south of the Lewis laboratory in Cleveland, Ohio. The aircraft were excess military transports from World War II. The aircraft was guided down the runway at speeds of 80 to 105 miles per hour. It came into contact with poles which tore open the 1500-gallon fuel tanks in the wings before reaching the barriers at the end of the runway. Fuel poured from the tanks and supply lines, resulting in the spread of both liquid fuel and a large cloud of spray. Solomon Weiss developed a method of dying the fuel red to improve its visibility during the crashes. This red fuel cloud trailed slightly behind the skidding aircraft, then rushed forward when the aircraft stopped. The nine-crash initial phase of testing used Lockheed C-56 Lodestar and C-82 transport aircraft to identify potential ignition sources and analyze the spread of flammable materials. The researchers were able to identify different classes of ignition sources, fuel disbursement patterns, the time when a particular ignition source might appear, rate of the fire spread, cabin survival times, and deceleration rates.

Application of quadratic optimization to supersonic inlet control.

NASA Technical Reports Server (NTRS)

Lehtinen, B.; Zeller, J. R.

1972-01-01

This paper describes the application of linear stochastic optimal control theory to the design of the control system for the air intake, the inlet, of a supersonic air-breathing propulsion system. The controls must maintain a stable inlet shock position in the presence of random airflow disturbances and prevent inlet unstart. Two different linear time invariant controllers are developed. One is designed to minimize a nonquadratic index, the expected frequency of inlet unstart, and the other is designed to minimize the mean square value of inlet shock motion. The quadratic equivalence principle is used to obtain a linear controller that minimizes the nonquadratic index. The two controllers are compared on the basis of unstart prevention, control effort requirements, and frequency response. It is concluded that while controls designed to minimize unstarts are desirable in that the index minimized is physically meaningful, computation time required is longer than for the minimum mean square shock position approach. The simpler minimum mean square shock position solution produced expected unstart frequency values which were not significantly larger than those of the nonquadratic solution.

Reactive oxygen species mediate growth and death in submerged plants

PubMed Central

Steffens, Bianka; Steffen-Heins, Anja; Sauter, Margret

2013-01-01

Aquatic and semi-aquatic plants are well adapted to survive partial or complete submergence which is commonly accompanied by oxygen deprivation. The gaseous hormone ethylene controls a number of adaptive responses to submergence including adventitious root growth and aerenchyma formation. Reactive oxygen species (ROS) act as signaling intermediates in ethylene-controlled submergence adaptation and possibly also independent of ethylene. ROS levels are controlled by synthesis, enzymatic metabolism, and non-enzymatic scavenging. While the actors are by and large known, we still have to learn about altered ROS at the subcellular level and how they are brought about, and the signaling cascades that trigger a specific response. This review briefly summarizes our knowledge on the contribution of ROS to submergence adaptation and describes spectrophotometrical, histochemical, and live cell imaging detection methods that have been used to study changes in ROS abundance. Electron paramagnetic resonance (EPR) spectroscopy is introduced as a method that allows identification and quantification of specific ROS in cell compartments. The use of advanced technologies such as EPR spectroscopy will be necessary to untangle the intricate and partially interwoven signaling networks of ethylene and ROS. PMID:23761805

Diode Laser Sensor for Scramjet Inlet

DTIC Science & Technology

2010-05-11

This work presents the development of an oxygen -based diode laser absorption sensor designed to be used in a supersonic combustion ramjet engine inlet...ADFA Abstract This work presents development of an oxygen -based diode laser absorption sensor designed to be used in a supersonic combustion ramjet... sensor needs to use oxygen as the absorbing species, as this is the only option for absorption measurements in inlet air. Oxygen absorption lines

Effect of inlet modelling on surface drainage in coupled urban flood simulation

NASA Astrophysics Data System (ADS)

Jang, Jiun-Huei; Chang, Tien-Hao; Chen, Wei-Bo

2018-07-01

For a highly developed urban area with complete drainage systems, flood simulation is necessary for describing the flow dynamics from rainfall, to surface runoff, and to sewer flow. In this study, a coupled flood model based on diffusion wave equations was proposed to simulate one-dimensional sewer flow and two-dimensional overland flow simultaneously. The overland flow model provides details on the rainfall-runoff process to estimate the excess runoff that enters the sewer system through street inlets for sewer flow routing. Three types of inlet modelling are considered in this study, including the manhole-based approach that ignores the street inlets by draining surface water directly into manholes, the inlet-manhole approach that drains surface water into manholes that are each connected to multiple inlets, and the inlet-node approach that drains surface water into sewer nodes that are connected to individual inlets. The simulation results were compared with a high-intensity rainstorm event that occurred in 2015 in Taipei City. In the verification of the maximum flood extent, the two approaches that considered street inlets performed considerably better than that without street inlets. When considering the aforementioned models in terms of temporal flood variation, using manholes as receivers leads to an overall inefficient draining of the surface water either by the manhole-based approach or by the inlet-manhole approach. Using the inlet-node approach is more reasonable than using the inlet-manhole approach because the inlet-node approach greatly reduces the fluctuation of the sewer water level. The inlet-node approach is more efficient in draining surface water by reducing flood volume by 13% compared with the inlet-manhole approach and by 41% compared with the manhole-based approach. The results show that inlet modeling has a strong influence on drainage efficiency in coupled flood simulation.

Detecting submerged objects: the application of side scan sonar to forensic contexts.

PubMed

Schultz, John J; Healy, Carrie A; Parker, Kenneth; Lowers, Bim

2013-09-10

Forensic personnel must deal with numerous challenges when searching for submerged objects. While traditional water search methods have generally involved using dive teams, remotely operated vehicles (ROVs), and water scent dogs for cases involving submerged objects and bodies, law enforcement is increasingly integrating multiple methods that include geophysical technologies. There are numerous advantages for integrating geophysical technologies, such as side scan sonar and ground penetrating radar (GPR), with more traditional search methods. Overall, these methods decrease the time involved searching, in addition to increasing area searched. However, as with other search methods, there are advantages and disadvantages when using each method. For example, in instances with excessive aquatic vegetation or irregular bottom terrain, it may not be possible to discern a submersed body with side scan sonar. As a result, forensic personnel will have the highest rate of success during searches for submerged objects when integrating multiple search methods, including deploying multiple geophysical technologies. The goal of this paper is to discuss the methodology of various search methods that are employed for submerged objects and how these various methods can be integrated as part of a comprehensive protocol for water searches depending upon the type of underwater terrain. In addition, two successful case studies involving the search and recovery of a submerged human body using side scan sonar are presented to illustrate the successful application of integrating a geophysical technology with divers when searching for a submerged object. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Gas film retention and underwater photosynthesis during field submergence of four contrasting rice genotypes

PubMed Central

Winkel, Anders; Pedersen, Ole; Ella, Evangelina; Ismail, Abdelbagi M.; Colmer, Timothy D.

2014-01-01

Floods can completely submerge some rice (Oryza sativa L.) fields. Leaves of rice have gas films that aid O2 and CO2 exchange under water. The present study explored the relationship between gas film persistence and underwater net photosynthesis (PN) as influenced by genotype and submergence duration. Four contrasting genotypes (FR13A, IR42, Swarna, and Swarna-Sub1) were submerged for 13 days in the field and leaf gas films, chlorophyll, and the capacity for underwater PN at near ambient and high CO2 were assessed with time of submergence. At high CO2 during the PN assay, all genotypes initially showed high rates of underwater PN, and this rate was not affected by time of submergence in FR13A. This superior photosynthetic performance of FR13A was not evident in Swarna-Sub1 (carrying the SUB1 QTL) and the declines in underwater PN in both Swarna-Sub1 and Swarna were equal to that in IR42. At near ambient CO2 concentration, underwater PN declined in all four genotypes and this corresponded with loss of leaf gas films with time of submergence. FR13A retained leaf gas films moderately longer than the other genotypes, but gas film retention was not linked to SUB1. Diverse rice germplasm should be screened for gas film persistence during submergence, as this trait could potentially increase carbohydrate status and internal aeration owing to increased underwater PN, which contributes to submergence tolerance in rice. PMID:24759881

Potentiation of lead-induced cell death in PC12 cells by glutamate: Protection by N-acetylcysteine amide (NACA), a novel thiol antioxidant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Penugonda, Suman; Mare, Suneetha; Lutz, P.

2006-10-15

Oxidative stress has been implicated as an important factor in many neurological diseases. Oxidative toxicity in a number of these conditions is induced by excessive glutamate release and subsequent glutamatergic neuronal stimulation. This, in turn, causes increased generation of reactive oxygen species (ROS), oxidative stress, excitotoxicity, and neuronal damage. Recent studies indicate that the glutamatergic neurotransmitter system is involved in lead-induced neurotoxicity. Therefore, this study aimed to (1) investigate the potential effects of glutamate on lead-induced PC12 cell death and (2) elucidate whether the novel thiol antioxidant N-acetylcysteine amide (NACA) had any protective abilities against such cytotoxicity. Our results suggestmore » that glutamate (1 mM) potentiates lead-induced cytotoxicity by increased generation of ROS, decreased proliferation (MTS), decreased glutathione (GSH) levels, and depletion of cellular adenosine-triphosphate (ATP). Consistent with its ability to decrease ATP levels and induce cell death, lead also increased caspase-3 activity, an effect potentiated by glutamate. Exposure to glutamate and lead elevated the cellular malondialdehyde (MDA) levels and phospholipase-A{sub 2} (PLA{sub 2}) activity and diminished the glutamine synthetase (GS) activity. NACA protected PC12 cells from the cytotoxic effects of glutamate plus lead, as evaluated by MTS assay. NACA reduced the decrease in the cellular ATP levels and restored the intracellular GSH levels. The increased levels of ROS and MDA in glutamate-lead treated cells were significantly decreased by NACA. In conclusion, our data showed that glutamate potentiated the effects of lead-induced PC12 cell death by a mechanism involving mitochondrial dysfunction (ATP depletion) and oxidative stress. NACA had a protective role against the combined toxic effects of glutamate and lead by inhibiting lipid peroxidation and scavenging ROS, thus preserving intracellular GSH.« less

Mach 4 Test Results of a Dual-Flowpath, Turbine Based Combined Cycle Inlet

NASA Technical Reports Server (NTRS)

Albertson, Cindy w.; Emami, Saied; Trexler, Carl A.

2006-01-01

An experimental study was conducted to evaluate the performance of a turbine based combined cycle (TBCC) inlet concept, consisting of a low speed turbojet inlet and high speed dual-mode scramjet inlet. The main objectives of the study were (1) to identify any interactions between the low and the high speed inlets during the mode transition phase in which both inlets are operating simultaneously and (2) to determine the effect of the low speed inlet operation on the performance of the high speed inlet. Tests were conducted at a nominal freestream Mach number of 4 using an 8 percent scale model representing a single module of a TBCC inlet. A flat plate was installed upstream of the model to produce a turbulent boundary layer which simulated the full-scale vehicle forebody boundary layer. A flowmeter/back pressure device, with remote actuation, was attached aft of the high speed inlet isolator to simulate the back pressure resulting from dual-mode scramjet combustion. Results indicate that the inlets did not interact with each other sufficiently to affect inlet operability. Flow spillage resulting from a high speed inlet unstart did not propagate far enough upstream to affect the low speed inlet. Also, a low speed inlet unstart did not cause the high speed inlet to unstart. The low speed inlet improved the performance of the high speed inlet at certain conditions by diverting a portion of the boundary layer generated on the forebody plate.

6. View southwest, culvert inlet with canal bank completely removed. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. View southwest, culvert inlet with canal bank completely removed. Left to right: back of headwall; tops of high inlet barrels; vertical transition wall between high inlet barrels and low, interior, inlet barrels; tops of low interior barrels; vertical heartening planks and low cutoff wall along former edge of canal bank; dewatered canal bed. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

Analysis of experimental results of the inlet for the NASA hypersonic research engine aerothermodynamic integration model. [wind tunnel tests of ramjet engine hypersonic inlets

NASA Technical Reports Server (NTRS)

Andrews, E. H., Jr.; Mackley, E. A.

1976-01-01

An aerodynamic engine inlet analysis was performed on the experimental results obtained at nominal Mach numbers of 5, 6, and 7 from the NASA Hypersonic Research Engine (HRE) Aerothermodynamic Integration Model (AIM). Incorporation on the AIM of the mixed-compression inlet design represented the final phase of an inlet development program of the HRE Project. The purpose of this analysis was to compare the AIM inlet experimental results with theoretical results. Experimental performance was based on measured surface pressures used in a one-dimensional force-momentum theorem. Results of the analysis indicate that surface static-pressure measurements agree reasonably well with theoretical predictions except in the regions where the theory predicts large pressure discontinuities. Experimental and theoretical results both based on the one-dimensional force-momentum theorem yielded inlet performance parameters as functions of Mach number that exhibited reasonable agreement. Previous predictions of inlet unstart that resulted from pressure disturbances created by fuel injection and combustion appeared to be pessimistic.

Draftsmen Create a Blade Template in the Materials and Stresses Building

NASA Image and Video Library

1953-04-21

Draftsmen in the Materials and Stresses Building at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory create a template for a compressor using actual compressor blades. The Compressor and Turbine Division contained four sections of researchers dedicated to creating better engine components. The Materials and Thermodynamics Division studied the strength, durability, heat transfer characteristics, and physical composition of various materials. The two divisions were important to the research and development of new aircraft engines. The constant battle to increase the engine’s thrust while decreasing its overall weight resulted in additional stress on jet engine components, particularly compressors. As speed and maneuverability were enhanced, the strain on the engines and inlets grew. For decades NACA Lewis researchers continually sought to improve compressor blade design, develop stronger composite materials, and minimize flutter and inlet distortions.

Status of an inlet configuration trade study for the Douglas HSCT

NASA Technical Reports Server (NTRS)

Jones, Jay R.; Welge, H. Robert

1992-01-01

An inlet concept integration trade study for an HSCT is being conducted under contract to NASA LeRC. The HSCT mission has a supersonic cruise Mach number of 2.4 and a subsonic cruise Mach number of 0.95. The engine selected for this study is the GE VCE (variable cycle engine) with FLADE (fan on blade). Six inlet configurations will be defined. Inlet configurations will be axisymmetric and rectangular mixed-compression inlets in single-engine nacelles. Airplane performance for each inlet configuration will be estimated and then compared. The most appropriate inlet configuration for this airplane/engine combination will be determined by Sep. 1991.

NACA Aircraft in hangar 1953 - clockwise from front center: YF-84A, D-558-1, D-558-2, B-47, X-1 ship

NASA Technical Reports Server (NTRS)

1953-01-01

In the center foreground of this 1953 hanger photo is the YF-84A (NACA 134/Air Force 45-59490) used for vortex generator research. It arrived on November 28, 1949, and departed on April 21, 1954. Beside it is the third D-558-1 aircraft (NACA 142/Navy 37972). This aircraft was used for a total of 78 transonic research flights from April 1949 to June 1954. It replaced the second D-558-1, lost in the crash which killed Howard Lilly. Just visible on the left edge is the nose of the first D-558-2 (NACA 143/Navy 37973). Douglas turned the aircraft over to NACA on August 31, 1951, after the contractor had completed its initial test flights. NACA only made a single flight with the aircraft, on September 17, 1956, before the program was cancelled. In the center of the photo is the B-47A (NACA 150/Air Force 49-1900). The B-47 jet bomber, with its thin, swept-back wings, and six podded engines, represented the state of the art in aircraft design in the early 1950s. The aircraft undertook a number of research activities between May 1953 and its 78th and final research flight on November 22, 1957. The tests showed that the aircraft had a buffeting problem at speeds above Mach 0.8. Among the pilots who flew the B-47 were later X-15 pilots Joe Walker, A. Scott Crossfield, John B. McKay, and Neil A. Armstrong. On the right side of the B-47 is NACA's X-1 (Air Force 46-063). The second XS-1 aircraft built, it was fitted with a thicker wing than that on the first aircraft, which had exceeded Mach 1 on October 14, 1947. Flight research by NACA pilots indicated that this thicker wing produced 30 percent more drag at transonic speeds compared to the thinner wing on the first X-1. After a final flight on October 23, 1951, the aircraft was grounded due to the possibility of fatigue failure of the nitrogen spheres used to pressurize the fuel tanks. At the time of this photo, in 1953, the aircraft was in storage. In 1955, the aircraft was extensively modified, becoming the X-1E. In front of

Investigation of the effects of inlet shapes on fan noise radiation

NASA Technical Reports Server (NTRS)

Clark, T. L.; Slotboom, D. R.; Vaidya, P. G.

1981-01-01

The effect of inlet shape on forward radiated fan tone noise directivities was investigated under experimentally simplified zero flow conditions. Simulated fan tone noise was radiated to the far field through various shaped zero flow inlets. Baseline data were collected for the simplest baffled and unbaffled straight pipe inlets. These data compared well with prediction. The more general inlet shapes tested were the conical, circular, and exponential surfaces of revolution and an asymmetric inlet achieved by cutting a straight pipe inlet at an acute angle. Approximate theories were developed for these general shapes and some comparisons with data are presented. The conical and exponential shapes produced directivities that differed considerably from the baseline data while the circular shape produced directivities similar to the baseline data. The asymmetric inlet produced asymmetric directivities with significant reductions over the straight pipe data for some angles.

Determination of Boundary-Layer Transition on Three Symmetrical Airfoils in the NACA Full-Scale Wind Tunnel

NASA Technical Reports Server (NTRS)

Silverstein, Abe; Becker, John V

1938-01-01

For the purpose of studying the transition from laminar to turbulent flow, boundary-layer measurements were made in the NACA full-scale wind tunnel on three symmetrical airfoils of NACA 0009, 0012, and 0018 sections. The effects of variations in lift coefficient, Reynolds number, and airfoil thickness on transition were investigated. Air speed in the boundary layer was measured by total-head tubes and by hot wires; a comparison of transition as indicated by the two techniques was obtained. The results indicate no unique value of Reynolds number for the transition, whether the Reynolds number is based upon the distance along the chord or upon the thickness of the boundary layer at the transition point. In general, the transition is not abrupt and occurs in a region that varies in length as a function of the test conditions.

High-speed inlet research program and supporting analysis

NASA Technical Reports Server (NTRS)

Coltrin, Robert E.

1990-01-01

The technology challenges faced by the high speed inlet designer are discussed by describing the considerations that went into the design of the Mach 5 research inlet. It is shown that the emerging three dimensional viscous computational fluid dynamics (CFD) flow codes, together with small scale experiments, can be used to guide larger scale full inlet systems research. Then, in turn, the results of the large scale research, if properly instrumented, can be used to validate or at least to calibrate the CFD codes.

A comparison of predicted and measured inlet distortion flows in a subsonic axial inlet flow compressor rotor

NASA Technical Reports Server (NTRS)

Owen, Albert K.

1992-01-01

Detailed flow measurements were taken inside an isolated axial compressor rotor operating subsonically near peak efficiency. These Laser Anemometer measurements were made with two inlet velocity profiles. One profile consisted of an unmodified baseline flow, and the second profile was distorted by placing axisymmetric screens on the hub and shroud well upstream of the rotor. A detailed comparison in the rotor relative reference frame between a Navier-Stokes solver and the measured experimental results showed good agreement between the predicted and measured flows. A primary flow is defined in the rotor and deviations and the computed predictions is made to assess the development of a passage vortex due to the distortion of the inlet flow. Computer predictions indicate that a distorted inlet profile has a minimal effect on the development of the flow in the rotor passage and the resulting passage vortex.

Gas film retention and underwater photosynthesis during field submergence of four contrasting rice genotypes.

PubMed

Winkel, Anders; Pedersen, Ole; Ella, Evangelina; Ismail, Abdelbagi M; Colmer, Timothy D

2014-07-01

Floods can completely submerge some rice (Oryza sativa L.) fields. Leaves of rice have gas films that aid O2 and CO2 exchange under water. The present study explored the relationship between gas film persistence and underwater net photosynthesis (PN) as influenced by genotype and submergence duration. Four contrasting genotypes (FR13A, IR42, Swarna, and Swarna-Sub1) were submerged for 13 days in the field and leaf gas films, chlorophyll, and the capacity for underwater PN at near ambient and high CO2 were assessed with time of submergence. At high CO2 during the PN assay, all genotypes initially showed high rates of underwater PN, and this rate was not affected by time of submergence in FR13A. This superior photosynthetic performance of FR13A was not evident in Swarna-Sub1 (carrying the SUB1 QTL) and the declines in underwater PN in both Swarna-Sub1 and Swarna were equal to that in IR42. At near ambient CO2 concentration, underwater PN declined in all four genotypes and this corresponded with loss of leaf gas films with time of submergence. FR13A retained leaf gas films moderately longer than the other genotypes, but gas film retention was not linked to SUB1. Diverse rice germplasm should be screened for gas film persistence during submergence, as this trait could potentially increase carbohydrate status and internal aeration owing to increased underwater PN, which contributes to submergence tolerance in rice. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Design of Modular, Shape-transitioning Inlets for a Conical Hypersonic Vehicle

NASA Technical Reports Server (NTRS)

Gollan, Rowan J.; Smart, Michael K.

2010-01-01

For a hypersonic vehicle, propelled by scramjet engines, integration of the engines and airframe is highly desirable. Thus, the forward capture shape of the engine inlet should conform to the vehicle body shape. Furthermore, the use of modular engines places a constraint on the shape of the inlet sidewalls. Finally, one may desire a combustor cross- section shape that is different from that of the inlet. These shape constraints for the inlet can be accommodated by employing a streamline-tracing and lofting technique. This design technique was developed by Smart for inlets with a rectangular-to-elliptical shape transition. In this paper, we generalise that technique to produce inlets that conform to arbitrary shape requirements. As an example, we show the design of a body-integrated hypersonic inlet on a winged-cone vehicle, typical of what might be used in a three-stage orbital launch system. The special challenge of inlet design for this conical vehicle at an angle-of-attack is also discussed. That challenge is that the bow shock sits relatively close to the vehicle body.

[Influence of Submerged Plants on Microbial Community Structure in Sediment of Hongze Lake].

PubMed

Zhang, Ding-yu; Zhang, Ting-xi; Dong, Dan-ping; Li, De-fang; Wang, Guo-xiang

2016-05-15

Phospholipid fatty acids (PLFAs) method was applied to analyze the influence of submerged plants on sediment microbial community structure, in order to investigate the changes of sediment microbial community structure for different kinds of the submerged plants in different growth periods. Particularly, Potamogeton crispus L., Potamogeton pectinatus L and the mixed group were chosen as the typical submerged plants in Hongze Lake for investigation in this paper. The results indicated that the change of total PLFAs in different periods was significant, on the contrary, the PLFA change for different groups in the same period was insignificant. The values of G⁺ PLFA/G⁻ PLFA in the submerged plant group were also highly related to the different growth periods, which demonstrated that the root function of the submerged plant had a severe impact on the microbial community in sediment. Furthermore, some environmental factors, such as Temperature, pH, TOC and DO, were correlated to characteristic phospholipid of PLFAs in sediment, which means the environmental factors could also affect the microbial community structure.

Control of Inflow Distortion in a Scarf Inlet

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.; Clark, Lorenzo R.; Biedron, Robert T.

2002-01-01

The scarf inlet has the potential to reduce aircraft inlet noise radiation to the ground by reflecting it into the space above the engine. Without forward motion of the engine, the non-symmetry of the inlet causes inflow distortion which generates noise that is greater than the noise reduction of the scarf. However, acoustic evaluations of aircraft engines are often done on static test stands. A method to reduce inflow distortion by boundary layer suction is proposed and evaluated using a model of a high bypass ratio engine located in an anechoic chamber. The design goal of the flow control system is to make the inflow to the inlet circumferentially uniform and to eliminate reversed flow. This minimizes the inflow distortion and allows for acoustic evaluation of the scarf inlet on a static test stand. The inlet boundary layer suction effectiveness is evaluated both by aerodynamic and by acoustic measurements. Although the design goal is not met, the control system is found to have a beneficial effect on the engine operation, reducing blade stall and speed variation. This is quantified by two acoustic benefits, reduction both of the variability of tone noise and of the low frequency wideband noise due to the inflow distortion. It is felt that a compromise in the manufacture of the control hardware contributes to the inability of the control system to perform as expected from the analysis. The control system with sufficient authority is felt to have the potential to permit reliable acoustic testing in a static configuration of engines with non-symmetric inlets. Because the control system can improve operation of the engine, it may also have the potential to reduce noise and vibration and enhance engine longevity during low speed ground operations in the terminal area.

Summary of NACA Research on Afterburners for Turbojet Engines

NASA Technical Reports Server (NTRS)

Lundin, Bruce T; Gabriel, David S; Fleming, William A

1956-01-01

NACA research on afterburners for turbojet engines during the past 5 years is summarized. Although most of this work has been directed toward the development of specific afterburners for various engines rather than toward the accumulation of systematic data, it has, nevertheless, provided a large fund of experimental data and experience in the field. The references cited present over 1000 afterburner configurations and some 3500 hours of operation. In the treatment of the material of this summary, the principal effort has been to convey to the reader the "know-how" acquired by research engineers in the course of the work rather than to formulate a set of design rules.

High-speed inlet research program and supporting analyses

NASA Technical Reports Server (NTRS)

Coltrin, Robert E.

1987-01-01

A Mach 5 cruise aircraft was studied in a joint program effort. The propulsion system chosen for this aircraft was an over-under turbojet/ramjet system. The ramjet portion of the inlet is to be tested in NASA Lewis' 10 x 10 SWT. Goals of the test program are to obtain performance data and bleed requirements, and also to obtain analysis code validation data. Supporting analysis of the inlet using a three-dimensional Navier-Stokes code (PEPSIS) indicates that sidewall shock/boundary layer interactions cause large separated regions in the corners underneath the cowl. Such separations generally lead to inlet unstart, and are thus a major concern. As a result of the analysis, additional bleed regions were added to the inlet model sidewalls and cowl to control separations in the corners. A two-dimensional analysis incorporating bleed on the ramp is also presented. Supporting experiments for the Mach 5 programs were conducted in the Lewis' 1 x 1 SWT. A small-scale model representing the inlet geometry up to the ramp shoulder and cowl lip was tested to verify the accelerator plate test technique and to obtain data on flow migration in the ramp and sidewall boundary layers. Another study explored several ramp bleed configurations to control boundary layer separations in that region. Design of a two-dimensional Mach 5 cruise inlet represents several major challenges including multimode operation and dual flow, high temperatures, and three-dimensional airflow effects.

Submergence Confers Immunity Mediated by the WRKY22 Transcription Factor in Arabidopsis[W

PubMed Central

Hsu, Fu-Chiun; Chou, Mei-Yi; Chou, Shu-Jen; Li, Ya-Ru; Peng, Hsiao-Ping; Shih, Ming-Che

2013-01-01

Transcriptional control plays an important role in regulating submergence responses in plants. Although numerous genes are highly induced during hypoxia, their individual roles in hypoxic responses are still poorly understood. Here, we found that expression of genes that encode members of the WRKY transcription factor family was rapidly and strongly induced upon submergence in Arabidopsis thaliana, and this induction correlated with induction of a large portion of innate immunity marker genes. Furthermore, prior submergence treatment conferred higher resistance to the bacterial pathogen Pseudomonas syringae in Arabidopsis. Among the WRKY genes tested, WRKY22 had the highest level of induction during the early stages of submergence. Compared with the wild type, WRKY22 T-DNA insertion mutants wrky22-1 and wrky22-2 had lower disease resistance and lower induction of innate immunity markers, such as FLG22-INDUCED RECEPTOR-LIKE KINASE1 (FRK1) and WRKY53, after submergence. Furthermore, transcriptomic analyses of wrky22-2 and chromatin immunoprecipitation identified several potential targets of WRKY22, which included genes encoding a TIR domain–containing protein, a plant peptide hormone, and many OLIGO PEPTIDE TRANSPORTER genes, all of which may lead to induction of innate immunity. In conclusion, we propose that submergence triggers innate immunity in Arabidopsis via WRKY22, a response that may protect against a higher probability of pathogen infection either during or after flooding. PMID:23897923

Dynamic stall experiments on the NACA 0012 airfoil

NASA Technical Reports Server (NTRS)

Mcalister, K. W.; Carr, L. W.; Mccroskey, W. J.

1978-01-01

The flow over a NACA 0012 airfoil undergoing large oscillations in pitch was experimentally studied at a Reynolds number of and over a range of frequencies and amplitudes. Hot-wire probes and surface-pressure transducers were used to clarify the role of the laminar separation bubble, to delineate the growth and shedding of the stall vortex, and to quantify the resultant aerodynamic loads. In addition to the pressure distributions and normal force and pitching moment data that have often been obtained in previous investigations, estimates of the unsteady drag force during dynamic stall have been derived from the surface pressure measurements. Special characteristics of the pressure response, which are symptomatic of the occurrence and relative severity of moment stall, have also been examined.

Interference of Wing and Fuselage from Tests of 209 Combinations in the NACA Variable-Density Tunnel

NASA Technical Reports Server (NTRS)

Jacobs, Eastman N; Ward, Kenneth E

1936-01-01

This report presents the results of tests of 209 simple wing-fuselage combinations made in the NACA variable-density wind tunnel to provide information regarding the effects of aerodynamic interference between wings and fuselages at a large value of Reynolds number.

Rice SUB1A constrains remodeling of the transcriptome and metabolome during submergence and post-submergence recovery”.

USDA-ARS?s Scientific Manuscript database

The rice (Oryza sativa L.) ethylene-responsive transcription factor SUB1A confers tolerance to prolonged, complete submergence by limiting underwater elongation growth. Rice encoding SUB1A-1 also recovers photosynthetic function and re-commences development towards flowering more rapidly after desu...

Geodynamic settings of microcontinents, non-volcanic islands and submerged continental marginal plateau formation

NASA Astrophysics Data System (ADS)

Dubinin, Evgeny; Grokholsky, Andrey; Makushkina, Anna

2016-04-01

Complex process of continental lithosphere breakup is often accompanied by full or semi isolation of small continental blocks from the parent continent such as microcontinents or submerged marginal plateaus. We present different types of continental blocks formed in various geodynamic settings. The process depends on thermo-mechanical properties of rifting. 1) The continental blocks fully isolated from the parent continent. This kind of blocks exist in submerged form (Elan Bank, the Jan-Mayen Ridge, Zenith Plateau, Gulden Draak Knoll, Batavia Knoll) and in non-submerged form in case of large block size. Most of listed submerged blocks are formed in proximity of hot-spot or plume. 2) The continental blocks semi-isolated from the parent continent. Exmouth Plateau, Vøring, Agulhas, Naturaliste are submerged continental plateaus of the indicated category; Sri Lanka, Tasmania, Socotra are islands adjacent to continent here. Nowadays illustration of this setting is the Sinai block located between the two continental rifts. 3) The submerged linear continental blocks formed by the continental rifting along margin (the Lomonosov Ridge). Suggested evolution of this paragraph is the rift propagation along existing transtensional (or another type) transform fault. Future example of this type might be the California Peninsula block, detached from the North American plate by the rifting within San-Andreas fault. 4) The submerged continental blocks formed by extensional processes as the result of asthenosphere flow and shear deformations. Examples are submerged blocks in the central and southern Scotia Sea (Terror Bank, Protector Basin, Discovery Bank, Bruce Bank etc.). 5) The continental blocks formed in the transform fault systems originated in setting of contradict rifts propagation in presence of structure barriers, rifts are shifted by several hundreds kilometers from each other. Examples of this geodynamic setting are Equatorial Atlantic at the initial development stage

Analysis of Buzz in a Supersonic Inlet

NASA Technical Reports Server (NTRS)

Chima, Rodrick V.

2012-01-01

A dual-stream, low-boom supersonic inlet designed for use on a small, Mach 1.6 aircraft was tested experimentally in the 8- by 6-Foot Supersonic Wind Tunnel (SWT) at the NASA Glenn Research Center (GRC). The tests showed that the inlet had good recovery and stable operation over large mass flow range. The inlet went into buzz at mass flows well below that needed for engine operation, and the experiments generated a wealth of data during buzz. High frequency response pressure measurements and high-speed schlieren videos were recorded for many buzz events. The objective of the present work was to use computational fluid dynamics (CFD) to predict some of the experimental data taken during buzz, compare those predictions to the experimental data, and to use both datasets to explain the physics of the buzz cycle. The calculations were done with the Wind-US CFD code using a second-order time-accurate differencing scheme and the SST turbulence model. Computed Mach number contours were compared with schlieren images, and ensemble-averaged unsteady pressures were compared to data. The results showed that the buzz cycle consisted partly of spike buzz, an unsteady oscillation of the main shock at the spike tip while the inlet pressure dropped, and partly of choked flow while the inlet repressurized. Most of the results could be explained by theory proposed by Dailey in 1954, but did not support commonly used acoustic resonance explanations.

Design and Analysis Tool for External-Compression Supersonic Inlets

NASA Technical Reports Server (NTRS)

Slater, John W.

2012-01-01

A computational tool named SUPIN has been developed to design and analyze external-compression supersonic inlets for aircraft at cruise speeds from Mach 1.6 to 2.0. The inlet types available include the axisymmetric outward-turning, two-dimensional single-duct, two-dimensional bifurcated-duct, and streamline-traced Busemann inlets. The aerodynamic performance is characterized by the flow rates, total pressure recovery, and drag. The inlet flowfield is divided into parts to provide a framework for the geometry and aerodynamic modeling and the parts are defined in terms of geometric factors. The low-fidelity aerodynamic analysis and design methods are based on analytic, empirical, and numerical methods which provide for quick analysis. SUPIN provides inlet geometry in the form of coordinates and surface grids useable by grid generation methods for higher-fidelity computational fluid dynamics (CFD) analysis. SUPIN is demonstrated through a series of design studies and CFD analyses were performed to verify some of the analysis results.

Inlet flow field investigation. Part 1: Transonic flow field survey

NASA Technical Reports Server (NTRS)

Yetter, J. A.; Salemann, V.; Sussman, M. B.

1984-01-01

A wind tunnel investigation was conducted to determine the local inlet flow field characteristics of an advanced tactical supersonic cruise airplane. A data base for the development and validation of analytical codes directed at the analysis of inlet flow fields for advanced supersonic airplanes was established. Testing was conducted at the NASA-Langley 16-foot Transonic Tunnel at freestream Mach numbers of 0.6 to 1.20 and angles of attack from 0.0 to 10.0 degrees. Inlet flow field surveys were made at locations representative of wing (upper and lower surface) and forebody mounted inlet concepts. Results are presented in the form of local inlet flow field angle of attack, sideflow angle, and Mach number contours. Wing surface pressure distributions supplement the flow field data.

Pelvic Inlet Shape Is Not as Dimorphic as Previously Suggested.

PubMed

Delprete, Hillary

2017-04-01

It is well known that there are significant differences in the pelves of males and females due, in part, to differing constraints. The male and female pelves must be suitable for upright posture and locomotion, but the female pelvis must also be suitable for reproduction. These differing requirements lead to differences in the shape and size of various pelvic dimensions. These differences are reflected in the pelvic inlet, midplane, and outlet. Current research has documented dimorphisms in the posterior and anterior spaces in all three of these planes. One measure however, that is calculated from the relationship between the length of the anterior-posterior diameter (APD) and the transverse diameter (TD) of the inlet, is not as dimorphic as previously suggested. This computed value is used to describe four main categories of inlet shape: android, gynecoid, anthropoid, and platypelloid. Current textbooks in anatomy and midwifery describe these forms and identify the typical male inlet shape as android and the typical female inlet shape as gynecoid. In this study, however, using skeletonized pelves of 378 adult individuals from three identified skeletal collections, the most common inlet shape for both males and females was android. In addition, when examining shape as a continuous variable, inlet shape is not sexually dimorphic in two of the three populations examined in this study. Based on the results of this study, the inlet shape for males and females is less dimorphic than previously thought, and we need to discontinue using pelvic categories to describe typical inlet shape. Anat Rec, 300:706-715, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Aerodynamic and acoustic performance of high Mach number inlets

NASA Technical Reports Server (NTRS)

Lumsdaine, E.; Clark, L. R.; Cherng, J. C.; Tag, I.

1977-01-01

Experimental results were obtained for two types of high Mach number inlets, one with a translating centerbody and one with a fixed geometry (collapsing cowl) without centerbody. The aerodynamic and acoustic performance of these inlets was examined. The effects of several parameters such as area ratio and length-diameter ratio were investigated. The translating centerbody inlet was found to be superior to the collapsing cowl inlet both acoustically and aerodynamically, particularly for area ratios greater than 1.5. Comparison of length-diameter ratio and area ratio effects on performance near choked flow showed the latter parameter to be more significant. Also, greater high frequency noise attenuation was achieved by increasing Mach number from low to high subsonic values.

The Influence of Directed Air Flow on Combustion in Spark-Ignition Engine

NASA Technical Reports Server (NTRS)

Rothrock, A M; Spencer, R C

1939-01-01

The air movement within the cylinder of the NACA combustion apparatus was regulated by using shrouded inlet valves and by fairing the inlet passage. Rates of combustion were determined at different inlet-air velocities with the engine speed maintained constant and at different engine speeds with the inlet-air velocity maintained approximately constant. The rate of combustion increased when the engine speed was doubled without changing the inlet-air velocity; the observed increase was about the same as the increase in the rate of combustion obtained by doubling the inlet-air velocity without changing the engine speed. Certain types of directed air movement gave great improvement in the reproducibility of the explosions from cycle to cycle, provided that other variables were controlled. Directing the inlet air past the injection valve during injection increased the rate of burning.

Buffeting of NACA 0012 airfoil at high angle of attack

NASA Astrophysics Data System (ADS)

Zhou, Tong; Dowell, Earl

2014-11-01

Buffeting is a fluid instability caused by flow separation or shock wave oscillations in the flow around a bluff body. Typically there is a dominant frequency of these flow oscillations called Strouhal or buffeting frequency. In prior work several researchers at Duke University have noted the analogy between the classic Von Karman Vortex Street behind a bluff body and the flow oscillations that occur for flow around a NACA 0012 airfoil at sufficiently large angle of attack. Lock-in is found for certain combinations of airfoil oscillation (pitching motion) frequencies and amplitudes when the frequency of the airfoil motion is sufficiently close to the buffeting frequency. The goal of this paper is to explore the flow around a static and an oscillating airfoil at high angle of attack by developing a method for computing buffet response. Simulation results are compared with experimental data. Conditions for the onset of buffeting and lock-in of a NACA 0012 airfoil at high angle of attack are determined. Effects of several parameters on lift coefficient and flow response frequency are studied including Reynolds number, angle of attack and blockage ratio of the airfoil size to the wind tunnel dimensions. Also more detailed flow field characteristics are determined. For a static airfoil, a universal Strouhal number scaling has been found for angles of attack from 30° to 90°, where the flow around airfoil is fully separated. For an oscillating airfoil, conditions for lock-in are discussed. Differences between the lock-in case and the unlocked case are also studied. The second affiliation: Duke University.

Cavitation in centrifugal pump with rotating walls of axial inlet device

NASA Astrophysics Data System (ADS)

Moloshnyi, O.; Sotnyk, M.

2017-08-01

The article deals with the analysis of cavitation processes in the flowing part of the double entry centrifugal pump. The analysis is conducted using numerical modeling of the centrifugal pump operating process in the software environment ANSYS CFX. Two models of the axial inlet device is researched. It is shaped by a cylindrical section and diffuser section in front of the impeller, which includes fairing. The walls of the axial inlet device rotate with the same speed as the pump rotor. The numerical experiment is conducted under the condition of the flow rate change and absolute pressure at the inlet. The analysis shows that the pump has the average statistical cavitation performance. The occurrence of the cavitation in the axial inlet device is after narrowing the cross-section of flow channel and at the beginning of the diffuser section. Additional sudden expansion at the outlet of the axial inlet diffuser section does not affect the cavitation characteristics of the impeller, however, improves cavitation characteristics of the axial inlet device. For considered geometric parameters of the axial inlet device the cavitation in the impeller begins earlier than in the axial inlet device. That is, the considered design of the axial inlet device will not be subjected to destruction at the ensuring operation without cavitation in the impeller.

Diode Laser Sensor for Scramjet Inlets

DTIC Science & Technology

2011-06-03

for all the tunnel tests in this report was electronically very simple and reasonably robust, it has two major drawbacks in its current form: the scan...input voltage signal, provided by a signal generator. In addition to the vibrating exciter, a pendulum of 0.25 m length and with a mass of 44.4 g at the... pendulum mass bouncing off the side of the inlet and hitting the inlet a second time. After tightening the set screw, the standard deviation upon impact

Computation of inlet reference plane flow-field for a subscale free-jet forebody/inlet model and comparison to experimental data

NASA Astrophysics Data System (ADS)

McClure, M. D.; Sirbaugh, J. R.

1991-02-01

The computational fluid dynamics (CFD) computer code PARC3D was used to predict the inlet reference plane (IRP) flow field for a side-mounted inlet and forebody simulator in a free jet for five different flow conditions. The calculations were performed for free-jet conditions, mass flow rates, and inlet configurations that matched the free-jet test conditions. In addition, viscous terms were included in the main flow so that the viscous free-jet shear layers emanating from the free-jet nozzle exit were modeled. A measure of the predicted accuracy was determined as a function of free-stream Mach number, angle-of-attack, and sideslip angle.

Cooling Tests of an Airplane Equipped with an NACA Cowling and a Wing-duct Cooling System

NASA Technical Reports Server (NTRS)

Turner, L I , Jr; Bierman, David; Boothy, W B

1941-01-01

Cooling tests were made of a Northrop A-17A attack airplane successively equipped with a conventional.NACA cowling and with a wing-duct cooling system. The method of cooling the engine by admitting air from the propeller slipstream into wing ducts, passing it first through the accessory compartment and then over the engine from rear to front, appeared to offer possibilities for improved engine cooling, increased cooling of the accessories, and better fairing of the power-plant installation. The results showed that ground cooling for the wing duct system without cowl flap was better than for the NACA cowling with flap; ground cooling was appreciably improved by installing a cowl flap. Satisfactory temperatures were maintained in both climb and high-speed flight, but, with the use of conventional baffles, a greater quantity of cooling air appeared to be required for the wing duct system.

The performance of a centrifugal compressor with high inlet prewhirl

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whitfield, A.; Abdullah, A.H.

1998-07-01

The performance requirements of centrifugal compressors usually include a broad operating range between surge and choke. This becomes increasingly difficult to achieve as increased pressure ratio is demanded. In order to suppress the tendency to surge and extend the operating range at low flow rates, inlet swirl is often considered through the application of inlet guide vanes. To generate high inlet swirl angles efficiently, an inlet volute has been applied as the swirl generator, and a variable geometry design developed in order to provide zero swirl. The variable geometry approach can be applied to increase the swirl progressively or tomore » switch rapidly from zero swirl to maximum swirl. The variable geometry volute and the swirl conditions generated are described. The performance of a small centrifugal compressor is presented for a wide range of inlet swirl angles. In addition to the basic performance characteristics of the compressor, the onsets of flow reversals at impeller inlet are presented, together with the development of pressure pulsations, in the inlet and discharge ducts, through to full surge. The flow rate at which surge occurred was shown, by the shift of the peak pressure condition and by the measurement of the pressure pulsations, to be reduced by over 40%.« less

Numerical Simulation of Boundary Layer Ingesting (BLI) Inlet-Fan Interaction

NASA Technical Reports Server (NTRS)

Giuliani, James; Chen, Jen-Ping; Beach, Timothy; Bakhle, Milind

2014-01-01

Future civil transport designs may incorporate engine inlets integrated into the body of the aircraft to take advantage of efficiency increases due to weight and drag reduction. Additional increases in engine efficiency are predicted if the inlet ingests the lower momentum boundary layer flow. Previous studies have shown, however, that efficiency benefits of Boundary Layer Ingesting (BLI) ingestion are very sensitive to the magnitude of fan and duct losses, and blade structural response to the non-uniform flow field that results from a BLI inlet has not been studied in-depth. This paper presents an effort to extend the modeling capabilities of an existing rotating turbomachinery unsteady analysis code to include the ability to solve the external and internal flow fields of a BLI inlet. The TURBO code has been a successful tool in evaluating fan response to flow distortions for traditional engine/inlet integrations, such as the development of rotating stall and inlet distortion through compressor stages. This paper describes the first phase of an effort to extend the TURBO model to calculate the external and inlet flowfield upstream of fan so that accurate pressure distortions that result from BLI configurations can be computed and used to analyze fan aerodynamics and structural response. To validate the TURBO program modifications for the BLI flowfield, experimental test data obtained by NASA for a flushmounted S-duct with large amounts of boundary layer ingestion was modeled. Results for the flow upstream and in the inlet are presented and compared to experimental data for several high Reynolds number flows to validate the modifications to the solver. Quantitative data is presented that indicates good predictive capability of the model in the upstream flow. A representative fan is attached to the inlet and results are presented for the coupled inlet/fan model. The impact on the total pressure distortion at the AIP after the fan is attached is examined.

Influence of Inlet / Shoal Complex on Adjacent Shorelines via Inlet Sink Method

DTIC Science & Technology

2012-07-01

Figure 4. Ebb shoal bathymetry, Vilano and Anastasia Islands, October 2010. -40 -30 -20 -10 0 10 20 30 -1000 0 1000 2000 3000 4000...at Anastasia State Park was accretional over all time periods from R-123 to R-125, and was both erosional and accretional through R-128. All time...submerged platform fronting Anastasia State Park (Morphologic Zones 6 and 7 in Fig. 11) which can either be considered part of: 1. a continuous beach

Investigation on removal pathways of Di 2-ethyl hexyl phthalate from synthetic municipal wastewater using a submerged membrane bioreactor.

PubMed

Zolfaghari, Mehdi; Drogui, Patrick; Seyhi, Brahima; Brar, Satinder Kaur; Buelna, Gerardo; Dubé, Rino; Klai, Nouha

2015-11-01

Highly hydrophobic Di 2-ethyl hexyl phthalate (DEHP) is one of the most prevalent plasticizers in wastewaters. Since its half-life in biological treatment is around 25days, it can be used as an efficiency indicator of wastewater treatment plant for the removal of hydrophobic emerging contaminants. In this study, the performance of submerged membrane bioreactor was monitored to understand the effect of DEHP on the growth of aerobic microorganisms. The data showed that the chemical oxygen demand (COD) and ammonia concentration were detected below 10 and 1.0mg/L, respectively for operating conditions of hydraulic retention time (HRT)=4 and 6hr, sludge retention time (SRT)=140day and sludge concentration between 11.5 and 15.8g volatile solid (VS)/L. The removal efficiency of DEHP under these conditions was higher and ranged between 91% and 98%. Results also showed that the removal efficiency of DEHP in biological treatment depended on the concentration of sludge, as adsorption is the main mechanism of its removal. For the submerged membrane bioreactor, the pore size is the pivotal factor for DEHP removal, since it determines the amount of soluble microbial products coming out of the process. Highly assimilated microorganisms increase the biodegradation rate, as 74% of inlet DEHP was biodegraded; however, the concentration of DEHP inside sludge was beyond the discharge limit. Understanding the fate of DEHP in membrane bioreactor, which is one of the most promising and futuristic treatment process could provide replacement for conventional processes to satisfy the future stricter regulations on emerging contaminants. Copyright © 2015. Published by Elsevier B.V.

Bimodal SLD Ice Accretion on a NACA 0012 Airfoil Model

NASA Technical Reports Server (NTRS)

Potapczuk, Mark; Tsao, Jen-Ching; King-Steen, Laura

2016-01-01

This presentation describes the results of ice accretion measurements on a NACA 0012 airfoil model, from the NASA Icing Research Tunnel, using an icing cloud composed of a bimodal distribution of Supercooled Large Droplets. The data consists of photographs, laser scans of the ice surface, and measurements of the mass of ice for each icing condition. The results of ice shapes accumulated as a result of exposure to an icing cloud with a bimodal droplet distribution were compared to the ice shapes resulting from an equivalent cloud composed of a droplet distribution with a standard bell curve shape.

Theoretical evaluation of engine auxiliary inlet design for supersonic V/STOL aircraft

NASA Technical Reports Server (NTRS)

Boles, Michael A.; Heavner, Richard L.

1988-01-01

A higher order panel method is used to evaluate the potential flow of a two dimensional supersonic V/STOL inlet. A non-symmetric analytical inlet model is developed to closely match a wind tunnel model. The analytical inlet is analyzed for flow characteristics around the lower cowl lip and auxiliary inlets. The results are obtained from the output of a computer program that is based on the Hess Panel Method which determines source strengths of panels distributed over a three dimensional body. The analytical model was designed for the implementation of drooped/translated cowl lip and auxiliary inlets as flow improvement concepts. A 40 or 70 degree droop lip can be incorporated on the inlet to determine if these geometry modifications result in flow improvements which may reduce the propensity for flow separation on the interior portion of the lip. Auxiliary inlets are employed to decrease the mass flow over the inlet lip. Thus, the peak flow velocity is reduced at the lip which also lessens the likelihood of flow separation on the interior portion of the lip. A 2, 4, and 6 inch translated lip can be employed to also decrease mass flow over the inlet lower lip in the same manner as the auxiliary inlet. The performance results of the flow improvement concepts show that three possible inlet configurations provide a situation where separation is less likely to occur. A 70 degree droop lip maintains flow conditions such that attached flow over the lower cowl lip may exist for the entire angle of attack range studied. A 0 degree droop and translated lip combination provides similar results for the angle of attack range. The third configuration consists of a 0 degree droop and auxiliary inlet combination. This configuration provides slightly less favorable results than the other two, but still allows for conditions favorable to attached flow within the inlet.

Model of the NACA's Aircraft Engine Research Laboratory during its Construction

NASA Image and Video Library

1942-08-21

Zella Morewitz poses with a model of the National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory, currently the NASA Glenn Research Center. The model was displayed in the Administration Building during the construction of the laboratory in the early 1940s. Detailed models of the individual test facilities were also fabricated and displayed in the facilities. The laboratory was built on a wedge of land between the Cleveland Municipal Airport on the far side and the deep curving valley etched by the Rocky River on the near end. Roughly only a third of the laboratory's semicircle footprint was initially utilized. Additional facilities were added to the remaining areas in the years after World War II. In the late 1950s the site was supplemented by the acquisition of additional adjacent land. Morewitz joined the NACA in 1935 as a secretary in the main office at the Langley Memorial Aeronautical Laboratory. In September 1940 she took on the task of setting up and guiding an office dedicated to the design of the NACA’s new engine research laboratory. Morewitz and the others in the design office transferred to Cleveland in December 1941 to expedite the construction. Morewitz served as Manager Ray Sharp’s secretary for six years and was a popular figure at the new laboratory. In December 1947 Morewitz announced her engagement to Langley researcher Sidney Batterson and moved back to Virginia.

Closed flume inlet efficiency.

DOT National Transportation Integrated Search

2014-04-01

The goal of the present study was to determine the efficiency of a specific culvert geometry, labeled as : Index 216 Closed Flume Inlet (CFI) in the FDOTs Design Standards, and to determine if geometric changes : affect the efficiency of the curre...

40 CFR 90.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2012 CFR

2012-07-01

... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

40 CFR 90.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

40 CFR 90.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2014 CFR

2014-07-01

... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

40 CFR 90.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

40 CFR 90.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

Active Flow Control on a Boundary-Layer-Ingesting Inlet

NASA Technical Reports Server (NTRS)

Gorton, Susan Althoff; Owens, Lewis R.; Jenkins, Luther N.; Allan, Brian G.; Schuster, Ernest P.

2004-01-01

Boundary layer ingestion (BLI) is explored as means to improve overall system performance for Blended Wing Body configuration. The benefits of BLI for vehicle system performance benefit are assessed with a process derived from first principles suitable for highly-integrated propulsion systems. This performance evaluation process provides framework within which to assess the benefits of an integrated BLI inlet and lays the groundwork for higher-fidelity systems studies. The results of the system study show that BLI provides a significant improvement in vehicle performance if the inlet distortion can be controlled, thus encouraging the pursuit of active flow control (AFC) as a BLI enabling technology. The effectiveness of active flow control in reducing engine inlet distortion was assessed using a 6% scale model of a 30% BLI offset, diffusing inlet. The experiment was conducted in the NASA Langley Basic Aerodynamics Research Tunnel with a model inlet designed specifically for this type of testing. High mass flow pulsing actuators provided the active flow control. Measurements were made of the onset boundary layer, the duct surface static pressures, and the mass flow through the duct and the actuators. The distortion was determined by 120 total pressure measurements located at the aerodynamic interface plane. The test matrix was limited to a maximum freestream Mach number of 0.15 with scaled mass flows through the inlet for that condition. The data show that the pulsed actuation can reduce distortion from 29% to 4.6% as measured by the circumferential distortion descriptor DC60 using less than 1% of inlet mass flow. Closed loop control of the actuation was also demonstrated using a sidewall surface static pressure as the response sensor.

Entropy considerations applied to shock unsteadiness in hypersonic inlets

NASA Astrophysics Data System (ADS)

Bussey, Gillian Mary Harding

The stability of curved or rectangular shocks in hypersonic inlets in response to flow perturbations can be determined analytically from the principle of minimum entropy. Unsteady shock wave motion can have a significant effect on the flow in a hypersonic inlet or combustor. According to the principle of minimum entropy, a stable thermodynamic state is one with the lowest entropy gain. A model based on piston theory and its limits has been developed for applying the principle of minimum entropy to quasi-steady flow. Relations are derived for analyzing the time-averaged entropy gain flux across a shock for quasi-steady perturbations in atmospheric conditions and angle as a perturbation in entropy gain flux from the steady state. Initial results from sweeping a wedge at Mach 10 through several degrees in AEDC's Tunnel 9 indicates the bow shock becomes unsteady near the predicted normal Mach number. Several curved shocks of varying curvature are compared to a straight shock with the same mean normal Mach number, pressure ratio, or temperature ratio. The present work provides analysis and guidelines for designing an inlet robust to off- design flight or perturbations in flow conditions an inlet is likely to face. It also suggests that inlets with curved shocks are less robust to off-design flight than those with straight shocks such as rectangular inlets. Relations for evaluating entropy perturbations for highly unsteady flow across a shock and limits on their use were also developed. The normal Mach number at which a shock could be stable to high frequency upstream perturbations increases as the speed of the shock motion increases and slightly decreases as the perturbation size increases. The present work advances the principle of minimum entropy theory by providing additional validity for using the theory for time-varying flows and applying it to shocks, specifically those in inlets. While this analytic tool is applied in the present work for evaluating the stability

Activation of respiratory muscles does not occur during cold-submergence in bullfrogs, Lithobates catesbeianus.

PubMed

Santin, Joseph M; Hartzler, Lynn K

2017-04-01

Semiaquatic frogs may not breathe air for several months because they overwinter in ice-covered ponds. In contrast to many vertebrates that experience decreased motor performance after inactivity, bullfrogs, Lithobates catesbeianus , retain functional respiratory motor processes following cold-submergence. Unlike mammalian hibernators with unloaded limb muscles and inactive locomotor systems, respiratory mechanics of frogs counterintuitively allow for ventilatory maneuvers when submerged. Thus, we hypothesized that bullfrogs generate respiratory motor patterns during cold-submergence to avoid disuse and preserve motor performance. Accordingly, we measured activity of respiratory muscles (buccal floor compressor and glottal dilator) via electromyography in freely behaving bullfrogs at 20 and 2°C. Although we confirm that ventilation cycles occur underwater at 20°C, bullfrogs did not activate either respiratory muscle when submerged acutely or chronically at 2°C. We conclude that cold-submerged bullfrogs endure respiratory motor inactivity, implying that other mechanisms, excluding underwater muscle activation, maintain a functional respiratory motor system throughout overwintering. © 2017. Published by The Company of Biologists Ltd.

Inhibition of the reverse mode of the Na+/Ca2+ exchange by KB-R7943 augments arrhythmogenicity in the canine heart during rapid heart rates.

PubMed

Shinada, Takuro; Hirayama, Yoshiyuki; Maruyama, Mitsunori; Ohara, Toshihiko; Yashima, Masaaki; Kobayashi, Yoshinori; Atarashi, Hirotsugu; Takano, Teruo

2005-07-01

To test the hypothesis that the reverse mode of the Na+/Ca2+ exchange augmented by a rapid heart rate has an antiarrhythmic effect by shortening the action potential duration, we examined the effects of KB-R7943 (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl] isothiourea methanesulfonate), a selective inhibitor of the reverse mode of the Na+/Ca2+ exchange, to attenuate this effect. We recorded the electrocardiogram, monophasic action potential (MAP), and left ventricular pressure in canine beating hearts. In comparison to the control, KB-R7943 significantly increased the QTc value and MAP duration. MAP alternans and left ventricular pressure alternans were observed after changing the cycle length to 300 milliseconds in the control studies. KB-R7943 magnified both types of alternans and produced spatially discordant alternans between right and left ventricles. Early after-depolarizations and nonsustained ventricular tachycardia occurred in the presence of KB-R7943. Our data suggest that the reverse mode of the Na+/Ca2+ exchange may contribute to suppression of arrhythmias by abbreviating action potential duration under pathophysiological conditions. This conclusion is based on further confirmation by future studies of the specificity of KB-R7943 for block of the reverse mode of the Na+/Ca2+ exchange.

Additional testing of the inlets designed for a tandem fan V/STOL nacelle

NASA Technical Reports Server (NTRS)

Ybarra, A. H.

1981-01-01

The wind tunnel testing of a scale model of a tandem fan nacelle designed for a type (subsonic cruise) V/STOL aircraft configuration is discussed. The performance for the isolated front inlet and for the combined front and aft inlets is reported. Model variables include front and aft inlets with aft inlet variations of short and long aft inlet cowls, with a shaft simulator and diffuser vortex generators, cowl lip fillets, and nacelle strakes. Inlet pressure recovery, distortion, and inlet angle-to-attack separation limits were evaluated at tunnel velocity from 0 to 240 knots, angles-of-attack from -10 to +40 degrees and inlet flow rates corresponding to throat Mach number from 0.0 to 0.6. Combined nacelle pitch and yaw runs up to 30 deg. were also made.

Everything You Need To Know To Have Successful NACA Conventions/Conferences, But Were Afraid To Ask.

ERIC Educational Resources Information Center

Fogg, Linda

1999-01-01

Campus activities planners are offered strategies to use to make the most of their time attending National Association for Campus Activities (NACA) conventions. Advice includes specific approaches for covering conference sessions and booths, gathering information, planning for campus performances, and having students learn from the convention…

Experimental Research on Optimizing Inlet Airflow of Wet Cooling Towers under Crosswind Conditions

NASA Astrophysics Data System (ADS)

Chen, You Liang; Shi, Yong Feng; Hao, Jian Gang; Chang, Hao; Sun, Feng Zhong

2018-01-01

A new approach of installing air deflectors around tower inlet circumferentially was proposed to optimize the inlet airflow and reduce the adverse effect of crosswinds on the thermal performance of natural draft wet cooling towers (NDWCT). And inlet airflow uniformity coefficient was defined to analyze the uniformity of circumferential inlet airflow quantitatively. Then the effect of air deflectors on the NDWCT performance was investigated experimentally. By contrast between inlet air flow rate and cooling efficiency, it has been found that crosswinds not only decrease the inlet air flow rate, but also reduce the uniformity of inlet airflow, which reduce NDWCT performance jointly. After installing air deflectors, the inlet air flow rate and uniformity coefficient increase, the uniformity of heat and mass transfer increases correspondingly, which improve the cooling performance. In addition, analysis on Lewis factor demonstrates that the inlet airflow optimization has more enhancement of heat transfer than mass transfer, but leads to more water evaporation loss.

An Interactive, Design and Educational Tool for Supersonic External-Compression Inlets

NASA Technical Reports Server (NTRS)

Benson, Thomas J.

1994-01-01

A workstation-based interactive design tool called VU-INLET was developed for the inviscid flow in rectangular, supersonic, external-compression inlets. VU-INLET solves for the flow conditions from free stream, through the supersonic compression ramps, across the terminal normal shock region and the subsonic diffuser to the engine face. It calculates the shock locations, the capture streamtube, and the additive drag of the inlet. The inlet geometry can be modified using a graphical user interface and the new flow conditions recalculated interactively. Free stream conditions and engine airflow can also be interactively varied and off-design performance evaluated. Flow results from VU-INLET can be saved to a file for a permanent record, and a series of help screens make the simulator easy to learn and use. This paper will detail the underlying assumptions of the models and the numerical methods used in the simulator.

Antioxidant activity of seedling growth in selected soybean genotypes (Glycine max (L.) Merrill) responses of submergence

NASA Astrophysics Data System (ADS)

Damanik, R. I.; Marbun, P.; Sihombing, L.

2016-08-01

In order to better understand the physiological and biochemical responses relating to direct seeding establishment in soybeans, the plant growth rate and antioxidative defense responses of seedlings in seven Indonesian soybean genotypes (Anjasmoro, Detam-1, Detam-2, Dieng, Grobogan, Tanggamus, and Willis) at different submergence periods (4, and 8 days) were examined. Twelve-day old seedlings were hydroponically grown in limited oxygen conditions. The results showed that the chlorophyll content in soybean seedlings was reduced beginning as early as 4 d under submerged condition, except for Detam-1, Detam-2, and Grobogan genotypes. The dry weight and protein concentration of seedlings were significantly higher at control condition (0 d) than those in submerged condition. The activities of superoxide dismutase (SOD) increased linearly until 8 d submerged for all genotypes. On the other hand, our results showed that catalase (CAT) and ascorbate peroxidase (APX) activities did not work together, meaning that CAT is activated and APX deactivated, or vice versa, in response to submergence conditions, except for Grobogan and Tanggamus genotypes which had an effect on both CAT and APX activities. Submergence stress led to a significant increase in glutathione reductase (GR) together with APX activity for Detam-2 and Dieng genotypes at 8 d submerged.

CFD application to supersonic/hypersonic inlet airframe integration. [computational fluid dynamics (CFD)

NASA Technical Reports Server (NTRS)

Benson, Thomas J.

1988-01-01

Supersonic external compression inlets are introduced, and the computational fluid dynamics (CFD) codes and tests needed to study flow associated with these inlets are outlined. Normal shock wave turbulent boundary layer interaction is discussed. Boundary layer control is considered. Glancing sidewall shock interaction is treated. The CFD validation of hypersonic inlet configurations is explained. Scramjet inlet modules are shown.

The Scale Effects of Engineered Inlets in Urban Hydrologic Processes

NASA Astrophysics Data System (ADS)

Shevade, L.; Montalto, F. A.

2017-12-01

Runoff from urban surfaces is typically captured by engineered inlets for conveyance to receiving water bodies or treatment plants. Normative hydrologic and hydraulic (H&H) modeling tools generally assume 100% efficient inlets, though observations by the authors suggest this assumption is invalid. The discrepancy is key since the more efficiently the inlet, the more linearly hydrologic processes scale with catchment area. Using several years of remote sensing, the observed efficiencies of urban green infrastructure (GI) facility inlets in New York City are presented, as a function of the morphological and climatological properties of their catchments and events. The rainfall-runoff response is modeled with EPA to assess the degree of inaccuracy that the assumption of efficient inlets introduces in block and neighborhood-scale simulations. Next, an algorithm is presented that incorporates inlet efficiency into SWMM and the improved predictive skill evaluated using Nash-Sutcliffe and root-mean-square error (RMSE). The results are used to evaluate the extent to which decentralized green stormwater management facilities positioned at the low points of urban catchments ought to be designed with larger capacities than their counterparts located further upslope.

Dynamics of the inlet system of a four-stroke engine

NASA Technical Reports Server (NTRS)

Boden, R H; Schecter, Harry

1944-01-01

Tests were run on a single-cylinder and a multicylinder four-stroke engine in order to determine the effect of the dynamics of the inlet system upon indicated mean effective pressure. Tests on the single-cylinder engine were made at various speeds, inlet valve timings, and inlet pipe lengths. These tests indicated that the indicated mean effective pressure could be raised considerably at any one speed by the use of a suitably long inlet pipe. Tests at other speeds with this length of pipe showed higher indicated mean effective pressure than with a very short pipe, although not so high as could be obtained with the pipe length adjusted for each speed. A general relation was discovered between optimum time of inlet valve closing and pipe length; namely, that longer pipes require later inlet valve closing in order to be fully effective. Tests were also made on three cylinders connected to a single pipe. With this arrangement, increased volumetric efficiency at low speed was obtainable by using a long pipe, but only with a sacrifice of volumetric efficiency at high speed. Volumetric efficiency at high speed was progressively lower as the pipe length was increased.

Experimental Investigation of Actuators for Flow Control in Inlet Ducts

NASA Astrophysics Data System (ADS)

Vaccaro, John; Elimelech, Yossef; Amitay, Michael

2010-11-01

Attractive to aircraft designers are compact inlets, which implement curved flow paths to the compressor face. These curved flow paths could be employed for multiple reasons. One of which is to connect the air intake to the engine embedded in the aircraft body. A compromise must be made between the compactness of the inlet and its aerodynamic performance. The aerodynamic purpose of inlets is to decelerate the oncoming flow before reaching the engine while minimizing total pressure loss, unsteadiness and distortion. Low length-to-diameter ratio inlets have a high degree of curvature, which inevitably causes flow separation and secondary flows. Currently, the length of the propulsion system is constraining the overall size of Unmanned Air Vehicles (UAVs), thus, smaller more efficient aircrafts could be realized if the propulsion system could be shortened. Therefore, active flow control is studied in a compact (L/D=1.5) inlet to improve performance metrics. Actuation from a spanwise varying coanda type ejector actuator and a hybrid coanda type ejector / vortex generator jet actuator is investigated. Special attention will be given to the pressure recovery at the AIP along with unsteady pressure signatures along the inlet surface and at the AIP.

A novel concept for subsonic inlet boundary-layer control

NASA Technical Reports Server (NTRS)

Miller, B. A.

1977-01-01

A self-bleeding method for boundary layer control is described and tested for a subsonic inlet designed to operate in the flowfield generated by high angles of attack. Naturally occurring surface static pressure gradients are used to remove the boundary layer from a separation-prone region of the inlet and to reinject it at a less critical location with a net performance gain. The results suggest that this self-bleeding method for boundary-layer control might be successfully applied to other inlets operating at extreme aerodynamic conditions.

Tidal inlet response to sediment infilling of the associated bay and possible implications of human activities: the Marennes-Oléron Bay and the Maumusson Inlet, France

NASA Astrophysics Data System (ADS)

Bertin, Xavier; Chaumillon, Eric; Sottolichio, Aldo; Pedreros, Rodrigo

2005-06-01

Tidal inlet characteristics are controlled by wave energy, tidal range, tidal prism, sediment supply and direction and rates of sand delivered to the inlet. This paper deals with the relations between inlet and lagoon evolutions, linked by the tidal prism. Our study is focused on the Maumusson Inlet and the Marennes-Oléron Bay (first oyster farming area in Europe), located on the western coast of France. The tidal range (2-6 m) and wave climate (mean height: 1.5 m) place this tidal inlet system in the mixed energy (tide, waves), tide-dominated category. The availability of high-resolution bathymetric data since 1824 permits to characterise and quantify accurately morphological changes of both the inlet and the tidal bay. Since 1824, sediment filling of the tidal bay has led to a 20% decrease in its water volume, and a 35% reduction of the inlet throat section. Furthermore, the bay is subjected to a very high anthropic pressure, mainly related to oyster farming. Thus, both natural and human-related processes seem relevant to explain high sedimentation rates. Current measurements, hydrodynamic modelling and cross-sectional area of the inlet throat are used in order to quantify tidal prism changes since 1824. Both flood and ebb tidal prism decreased by 35%. Decrease in the Marennes-Oléron Bay water volume is inferred to be responsible for a part of tidal prism decrease at the inlet. Tidal prisms decrease may also be explained by an increase in frictional resistance to tidal wave propagation, due to a general shoaling and oyster farms in the bay. A conceptual model is proposed, taking into account natural and human-related sedimentation processes, and explaining tidal inlet response to tidal bay evolutions.

Calculation of compressible flow in and about three-dimensional inlets with and without auxiliary inlets by a higher-order panel method

NASA Technical Reports Server (NTRS)

Hess, J. L.; Friedman, D. M.

1982-01-01

A three dimensional higher order panel method was specialized to the case of inlets with auxiliary inlets. The resulting program has a number of graphical input-output features to make it highly useful to the designer. The various aspects of the program are described instructions for its use are presented.

Current progress on truffle submerged fermentation: a promising alternative to its fruiting bodies.

PubMed

Tang, Ya-Jie; Liu, Rui-Sang; Li, Hong-Mei

2015-03-01

Truffle (Tuber spp.), also known as "underground gold," is popular in various cuisines because of its unique and characteristic aroma. Currently, truffle fruiting bodies are mostly obtained from nature and semi-artificial cultivation. However, the former source is scarce, and the latter is time-consuming, usually taking 4 to 12 years before harvest of the fruiting body. The truffle submerged fermentation process was first developed in Tang's lab as an alternative to its fruiting bodies. To the best of our knowledge, most reports of truffle submerged fermentation come from Tang's group. This review examines the current state of the truffle submerged fermentation process. First, the strategy to optimize the truffle submerged fermentation process is summarized; the final conditions yielded not only the highest reported truffle biomass but also the highest production of extracellular and intracellular polysaccharides. Second, the comparison of metabolites produced by truffle fermentation and fruiting bodies is presented, and the former were superior to the latter. Third, metabolites (i.e., volatile organic compounds, equivalent umami concentration, and sterol) derived from truffle fermentation could be regulated by fermentation process optimization. These findings indicated that submerged fermentation of truffles can be used for commercial production of biomass and metabolites as a promising alternative to generating its fruiting bodies in bioreactor.

Interactive calculation procedures for mixed compression inlets

NASA Technical Reports Server (NTRS)

Reshotko, Eli

1983-01-01

The proper design of engine nacelle installations for supersonic aircraft depends on a sophisticated understanding of the interactions between the boundary layers and the bounding external flows. The successful operation of mixed external-internal compression inlets depends significantly on the ability to closely control the operation of the internal compression portion of the inlet. This portion of the inlet is one where compression is achieved by multiple reflection of oblique shock waves and weak compression waves in a converging internal flow passage. However weak these shocks and waves may seem gas-dynamically, they are of sufficient strength to separate a laminar boundary layer and generally even strong enough for separation or incipient separation of the turbulent boundary layers. An understanding was developed of the viscous-inviscid interactions and of the shock wave boundary layer interactions and reflections.

Tank Tests of NACA Model 40 Series of Hulls for Small Flying Boats and Amphibians

NASA Technical Reports Server (NTRS)

Parkinson, John B; Dawson, John R

1937-01-01

The NACA model 40 series of flying-boat hull models consists of 2 forebodies and 3 afterbodies combined to provide several forms suitable for use in small marine aircraft. One forebody is the usual form with hollow bow sections and the other has a bottom surface that is completely developable from bow to step. The afterbodies include a short pointed afterbody with an extension for the tail surfaces, a long afterbody similar to that of a seaplane float but long enough to carry the tail surfaces, and a third obtained by fitting a second step in the latter afterbody. The various combinations were tested in the NACA Tank by the general method over a suitable range of loadings. Fixed-trim tests were made for all speeds likely to be used and free-to-trim tests were made at low speeds to slightly beyond the hump speed. The characteristics of the hulls at best trim angles have been deduced from the data of the tests at fixed trim angles and are given in the form of nondimensional coefficients applicable to any size hull.

40 CFR 81.54 - Cook Inlet Intrastate Air Quality Control Region.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Cook Inlet Intrastate Air Quality...) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of Air Quality Control Regions § 81.54 Cook Inlet Intrastate Air Quality Control Region. The Cook Inlet...

40 CFR 81.54 - Cook Inlet Intrastate Air Quality Control Region.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Cook Inlet Intrastate Air Quality...) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of Air Quality Control Regions § 81.54 Cook Inlet Intrastate Air Quality Control Region. The Cook Inlet...

40 CFR 81.54 - Cook Inlet Intrastate Air Quality Control Region.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Cook Inlet Intrastate Air Quality...) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of Air Quality Control Regions § 81.54 Cook Inlet Intrastate Air Quality Control Region. The Cook Inlet...

40 CFR 81.54 - Cook Inlet Intrastate Air Quality Control Region.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Cook Inlet Intrastate Air Quality...) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of Air Quality Control Regions § 81.54 Cook Inlet Intrastate Air Quality Control Region. The Cook Inlet...

40 CFR 81.54 - Cook Inlet Intrastate Air Quality Control Region.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Cook Inlet Intrastate Air Quality...) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of Air Quality Control Regions § 81.54 Cook Inlet Intrastate Air Quality Control Region. The Cook Inlet...

Evaluation of Flush-Mounted, S-Duct Inlets With Large Amounts of Boundary Layer Ingestion

NASA Technical Reports Server (NTRS)

Berrier, Bobby L.; Morehouse, Melissa B.

2003-01-01

A new high Reynolds number test capability for boundary layer ingesting inlets has been developed for the NASA Langley Research Center 0.3-Meter Transonic Cryogenic Tunnel. Using this new capability, an experimental investigation of four S-duct inlet configurations with large amounts of boundary layer ingestion (nominal boundary layer thickness of about 40% of inlet height) was conducted at realistic operating conditions (high subsonic Mach numbers and full-scale Reynolds numbers). The objectives of this investigation were to 1) develop a new high Reynolds number, boundary-layer ingesting inlet test capability, 2) evaluate the performance of several boundary layer ingesting S-duct inlets, 3) provide a database for CFD tool validation, and 4) provide a baseline inlet for future inlet flow-control studies. Tests were conducted at Mach numbers from 0.25 to 0.83, Reynolds numbers (based on duct exit diameter) from 5.1 million to a fullscale value of 13.9 million, and inlet mass-flow ratios from 0.39 to 1.58 depending on Mach number. Results of this investigation indicate that inlet pressure recovery generally decreased and inlet distortion generally increased with increasing Mach number. Except at low Mach numbers, increasing inlet mass-flow increased pressure recovery and increased distortion. Increasing the amount of boundary layer ingestion (by decreasing inlet throat height and increasing inlet throat width) or ingesting a boundary layer with a distorted profile decreased pressure recovery and increased distortion. Finally, increasing Reynolds number had almost no effect on inlet distortion but increased inlet recovery by about one-half percent at a Mach number near cruise.

Effects of stern-foil submerged elevation on the lift and drag of a hydrofoil craft

NASA Astrophysics Data System (ADS)

Suastika, K.; Apriansyah

2018-03-01

Effects of the stern-foil submerged elevation on the lift and drag of a hydrofoil craft are studied by using computational fluid dynamics (CFD) and by considering three alternative stern-foil submerged elevations. The submerged elevation of the front foil is kept constant in all the alternatives. From among the alternatives, the deepest stern-foil placement results in the highest stern-foil lift with the highest foil’s lift-to-drag ratio. However, considering the lift-to-drag ratio of the whole foil-strut-hull system, the shallowest stern-foil placement results in the highest lift-to-drag ratio. The struts and the foil’s submerged elevation significantly affects the drag of the whole foil-strut-hull system.

Hypersonic Magneto-Fluid-Dynamic Compression in Cylindrical Inlet

NASA Technical Reports Server (NTRS)

Shang, Joseph S.; Chang, Chau-Lyan

2007-01-01

Hypersonic magneto-fluid-dynamic interaction has been successfully performed as a virtual leading-edge strake and a virtual cowl of a cylindrical inlet. In a side-by-side experimental and computational study, the magnitude of the induced compression was found to be depended on configuration and electrode placement. To better understand the interacting phenomenon the present investigation is focused on a direct current discharge at the leading edge of a cylindrical inlet for which validating experimental data is available. The present computational result is obtained by solving the magneto-fluid-dynamics equations at the low magnetic Reynolds number limit and using a nonequilibrium weakly ionized gas model based on the drift-diffusion theory. The numerical simulation provides a detailed description of the intriguing physics. After validation with experimental measurements, the computed results further quantify the effectiveness of a magnet-fluid-dynamic compression for a hypersonic cylindrical inlet. At a minuscule power input to a direct current surface discharge of 8.14 watts per square centimeter of electrode area produces an additional compression of 6.7 percent for a constant cross-section cylindrical inlet.

Inlet and Propulsion Integration of Scram Propelled Vehicles

NASA Technical Reports Server (NTRS)

Povinelli, Louis A.

1996-01-01

The material to be presented in these two lectures begins with cycle considerations of the turbojet engine combined with a ramjet engine to provide thrust over the range of Mach 0 to 5. We will then examine in some detail the aerodynamic behavior that occurs in the inlet operating near the peak speed. Following that, we shall view a numerical simulation through a baseline scramjet engine, starting at the entrance to the inlet, proceeding into the combustor and through the nozzle. In the next segment, we examine a combined rocket and ramjet propulsion system. Analysis and test results will be examined with a view toward evaluation of the concept as a practical device. Two other inlets will then be reviewed: a Mach 12 inlet and a Mach 18 configuration. Finally, we close our lectures with a discussion of the Detonation Wave engine, and inspect the physical and chemical behavior obtained from numerical simulation. A few final remarks will be made regarding the application of CFD for hypersonic propulsion components.

Enhanced Performance of Streamline-Traced External-Compression Supersonic Inlets

NASA Technical Reports Server (NTRS)

Slater, John W.

2015-01-01

A computational design study was conducted to enhance the aerodynamic performance of streamline-traced, external-compression inlets for Mach 1.6. The current study explored a new parent flowfield for the streamline tracing and several variations of inlet design factors, including the axial displacement and angle of the subsonic cowl lip, the vertical placement of the engine axis, and the use of porous bleed in the subsonic diffuser. The performance was enhanced over that of an earlier streamline-traced inlet such as to increase the total pressure recovery and reduce total pressure distortion

The NASA Ames Hypersonic Combustor-Model Inlet CFD Simulations and Experimental Comparisons

NASA Technical Reports Server (NTRS)

Venkatapathy, E.; Tokarcik-Polsky, S.; Deiwert, G. S.; Edwards, Thomas A. (Technical Monitor)

1995-01-01

Computations have been performed on a three-dimensional inlet associated with the NASA Ames combustor model for the hypersonic propulsion experiment in the 16-inch shock tunnel. The 3-dimensional inlet was designed to have the combustor inlet flow nearly two-dimensional and of sufficient mass flow necessary for combustion. The 16-inch shock tunnel experiment is a short duration test with test time of the order of milliseconds. The flow through the inlet is in chemical non-equilibrium. Two test entries have been completed and limited experimental results for the inlet region of the combustor-model are available. A number of CFD simulations, with various levels of simplifications such as 2-D simulations, 3-D simulations with and without chemical reactions, simulations with and without turbulent conditions, etc., have been performed. These simulations have helped determine the model inlet flow characteristics and the important factors that affect the combustor inlet flow and the sensitivity of the flow field to these simplifications. In the proposed paper, CFD modeling of the hypersonic inlet, results from the simulations and comparison with available experimental results will be presented.

Vortex Generators in a Two-Dimensional, External-Compression Supersonic Inlet

NASA Technical Reports Server (NTRS)

Baydar, Ezgihan; Lu, Frank K.; Slater, John W.

2016-01-01

Vortex generators within a two-dimensional, external-compression supersonic inlet for Mach 1.6 were investigated to determine their ability to increase total pressure recovery, reduce total pressure distortion, and improve the boundary layer. The vortex generators studied included vanes and ramps. The geometric factors of the vortex generators studied included height, length, spacing, and positions upstream and downstream of the inlet terminal shock. The flow through the inlet was simulated through the computational solution of the steady-state Reynolds-averaged Navier-Stokes equations on multi-block, structured grids. The vortex generators were simulated by either gridding the geometry of the vortex generators or modeling the vortices generated by the vortex generators. The inlet performance was characterized by the inlet total pressure recovery, total pressure distortion, and incompressible shape factor of the boundary-layer at the engine face. The results suggested that downstream vanes reduced the distortion and improved the boundary layer. The height of the vortex generators had the greatest effect of the geometric factors.

Transmission geometry laserspray ionization vacuum using an atmospheric pressure inlet.

PubMed

Lutomski, Corinne A; El-Baba, Tarick J; Inutan, Ellen D; Manly, Cory D; Wager-Miller, James; Mackie, Ken; Trimpin, Sarah

2014-07-01

This represents the first report of laserspray ionization vacuum (LSIV) with operation directly from atmospheric pressure for use in mass spectrometry. Two different types of electrospray ionization source inlets were converted to LSIV sources by equipping the entrance of the atmospheric pressure inlet aperture with a customized cone that is sealed with a removable glass plate holding the matrix/analyte sample. A laser aligned in transmission geometry (at 180° relative to the inlet) ablates the matrix/analyte sample deposited on the vacuum side of the glass slide. Laser ablation from vacuum requires lower inlet temperature relative to laser ablation at atmospheric pressure. However, higher inlet temperature is required for high-mass analytes, for example, α-chymotrypsinogen (25.6 kDa). Labile compounds such as gangliosides and cardiolipins are detected in the negative ion mode directly from mouse brain tissue as intact doubly deprotonated ions. Multiple charging enhances the ion mobility spectrometry separation of ions derived from complex tissue samples.

Transmission Geometry Laserspray Ionization Vacuum Using an Atmospheric Pressure Inlet

PubMed Central

2015-01-01

This represents the first report of laserspray ionization vacuum (LSIV) with operation directly from atmospheric pressure for use in mass spectrometry. Two different types of electrospray ionization source inlets were converted to LSIV sources by equipping the entrance of the atmospheric pressure inlet aperture with a customized cone that is sealed with a removable glass plate holding the matrix/analyte sample. A laser aligned in transmission geometry (at 180° relative to the inlet) ablates the matrix/analyte sample deposited on the vacuum side of the glass slide. Laser ablation from vacuum requires lower inlet temperature relative to laser ablation at atmospheric pressure. However, higher inlet temperature is required for high-mass analytes, for example, α-chymotrypsinogen (25.6 kDa). Labile compounds such as gangliosides and cardiolipins are detected in the negative ion mode directly from mouse brain tissue as intact doubly deprotonated ions. Multiple charging enhances the ion mobility spectrometry separation of ions derived from complex tissue samples. PMID:24896880

Quasi One-Dimensional Unsteady Modeling of External Compression Supersonic Inlets

NASA Technical Reports Server (NTRS)

Kopasakis, George; Connolly, Joseph W.; Kratz, Jonathan

2012-01-01

The AeroServoElasticity task under the NASA Supersonics Project is developing dynamic models of the propulsion system and the vehicle in order to conduct research for integrated vehicle dynamic performance. As part of this effort, a nonlinear quasi 1-dimensional model of an axisymmetric external compression supersonic inlet is being developed. The model utilizes compressible flow computational fluid dynamics to model the internal inlet segment as well as the external inlet portion between the cowl lip and normal shock, and compressible flow relations with flow propagation delay to model the oblique shocks upstream of the normal shock. The external compression portion between the cowl-lip and the normal shock is also modeled with leaking fluxes crossing the sonic boundary, with a moving CFD domain at the normal shock boundary. This model has been verified in steady state against tunnel inlet test data and it s a first attempt towards developing a more comprehensive model for inlet dynamics.

Measurement of Submerged Oil/Gas Leaks using ROV Video

NASA Astrophysics Data System (ADS)

Shaffer, Franklin; de Vera, Giorgio; Lee, Kenneth; Savas, Ömer

2013-11-01

Drilling for oil or gas in the Gulf of Mexico is increasing rapidly at depths up to three miles. The National Commission on the Deepwater Horizon Oil Leak concluded that inaccurate estimates of the leak rate from the Deepwater Horizon caused an inadequate response and attempts to cap the leak to fail. The first response to a submerged oil/gas leak will be to send a Remotely Operated Vehicle (ROV) down to view the leak. During the response to the Deepwater Horizon crisis, the authors Savas and Shaffer were members of the Flow Rate Technical Group's Plume Team who used ROV video to develop the FRTG's first official estimates of the oil leak rate. Savas and Shaffer developed an approach using the larger, faster jet features (e.g., turbulent eddies, vortices, entrained particles) in the near-field developing zone to measure discharge rates. The authors have since used the Berkeley Tow Tank to test this approach on submerged dye-colored water jets and compressed air jets. Image Correlation Velocimetry has been applied to measure the velocity of visible features. Results from tests in the Berkeley Tow Tank and submerged oil jets in the OHMSETT facility will be presented.

Detecting submerged features in water: modeling, sensors, and measurements

NASA Astrophysics Data System (ADS)

Bostater, Charles R., Jr.; Bassetti, Luce

2004-11-01

It is becoming more important to understand the remote sensing systems and associated autonomous or semi-autonomous methodologies (robotic & mechatronics) that may be utilized in freshwater and marine aquatic environments. This need comes from several issues related not only to advances in our scientific understanding and technological capabilities, but also from the desire to insure that the risk associated with UXO (unexploded ordnance), related submerged mines, as well as submerged targets (such as submerged aquatic vegetation) and debris left from previous human activities are remotely sensed and identified followed by reduced risks through detection and removal. This paper will describe (a) remote sensing systems, (b) platforms (fixed and mobile, as well as to demonstrate (c) the value of thinking in terms of scalability as well as modularity in the design and application of new systems now being constructed within our laboratory and other laboratories, as well as future systems. New remote sensing systems - moving or fixed sensing systems, as well as autonomous or semi-autonomous robotic and mechatronic systems will be essential to secure domestic preparedness for humanitarian reasons. These remote sensing systems hold tremendous value, if thoughtfully designed for other applications which include environmental monitoring in ambient environments.

A Combined Experimental/Computational Investigation of a Rocket Based Combined Cycle Inlet

NASA Technical Reports Server (NTRS)

Smart, Michael K.; Trexler, Carl A.; Goldman, Allen L.

2001-01-01

A rocket based combined cycle inlet geometry has undergone wind tunnel testing and computational analysis with Mach 4 flow at the inlet face. Performance parameters obtained from the wind tunnel tests were the mass capture, the maximum back-pressure, and the self-starting characteristics of the inlet. The CFD analysis supplied a confirmation of the mass capture, the inlet efficiency and the details of the flowfield structure. Physical parameters varied during the test program were cowl geometry, cowl position, body-side bleed magnitude and ingested boundary layer thickness. An optimum configuration was determined for the inlet as a result of this work.

Linear Strength Vortex Panel Method for NACA 4412 Airfoil

NASA Astrophysics Data System (ADS)

Liu, Han

2018-03-01

The objective of this article is to formulate numerical models for two-dimensional potential flow over the NACA 4412 Airfoil using linear vortex panel methods. By satisfying the no penetration boundary condition and Kutta condition, the circulation density on each boundary points (end point of every panel) are obtained and according to which, surface pressure distribution and lift coefficients of the airfoil are predicted and validated by Xfoil, an interactive program for the design and analysis of airfoil. The sensitivity of results to the number of panels is also investigated in the end, which shows that the results are sensitive to the number of panels when panel number ranges from 10 to 160. With the increasing panel number (N>160), the results become relatively insensitive to it.

Inlet Flow Control and Prediction Technologies for Embedded Propulsion Systems

NASA Technical Reports Server (NTRS)

McMillan, Michelle L.; Mackie, Scott A.; Gissen, Abe; Vukasinovic, Bojan; Lakebrink, Matthew T.; Glezer, Ari; Mani, Mori; Mace, James L.

2011-01-01

Fail-safe, hybrid, flow control (HFC) is a promising technology for meeting high-speed cruise efficiency, low-noise signature, and reduced fuel-burn goals for future, Hybrid-Wing-Body (HWB) aircraft with embedded engines. This report details the development of HFC technology that enables improved inlet performance in HWB vehicles with highly integrated inlets and embedded engines without adversely affecting vehicle performance. In addition, new test techniques for evaluating Boundary-Layer-Ingesting (BLI)-inlet flow-control technologies developed and demonstrated through this program are documented, including the ability to generate a BLI-like inlet-entrance flow in a direct-connect, wind-tunnel facility, as well as, the use of D-optimal, statistically designed experiments to optimize test efficiency and enable interpretation of results. Validated improvements in numerical analysis tools and methods accomplished through this program are also documented, including Reynolds-Averaged Navier-Stokes CFD simulations of steady-state flow physics for baseline, BLI-inlet diffuser flow, as well as, that created by flow-control devices. Finally, numerical methods were employed in a ground-breaking attempt to directly simulate dynamic distortion. The advances in inlet technologies and prediction tools will help to meet and exceed "N+2" project goals for future HWB aircraft.

Inlet Reservoir Model. Part 2: PC-Interface

DTIC Science & Technology

2011-12-01

2008); and Zarillo and Kraus (2003). Figure 1 shows a schematic of an inlet system within the IRM with various types of reservoirs (e.g., channel...ERDC/CHL CHETN-IV-xx 2  Knowledge of engineering activities within the inlet system (e.g., dredging of a deposition basin or dredged channel...there to the Shore, S. As the first reservoir in the system , E, fills and its volume increases closer to the equilibrium (identified for all

Computational study of fuel injection in a shcramjet inlet

NASA Astrophysics Data System (ADS)

Parent, Bernard

The primary objective of this investigation is to present the mixing of fuel with air in the inlet of a shock-induced combustion ramjet (shcramjet). The study is limited to non-reacting hydrogen-air mixing in an external-compression inlet at a flight Mach number of 11 and at a dynamic pressure of 1400 psf (67032 Pa), using an array of cantilevered ramp injectors. A numerical method based on the Yee-Roe scheme and block-implicit approximate factorization is developed to solve the FANS equations closed by the Wilcox ko turbulence model. A new acceleration technique for streamwise-separated hypersonic flow, dubbed the "marching window", is presented. The dilatational dissipation correction is seen to affect the mixing efficiency considerably for a cantilevered ramp injector flowfield even at a vanishing convective Mach number, due to the high turbulent Mach number generated by the high cross-stream shear induced by the ramp-generated axial vortices. Due to the fuel being injected at a very high speed, fuel injection in the inlet is found to increase considerably the thrust potential, with a gain exceeding the loss by 40--120%. Losses due to skin friction are seen to play a significant role in the inlet, as they are estimated to make up as much as 50--70% of the thrust potential losses. The use of a turbulence model that can predict accurately the wall shear stress is hence crucial in assessing the losses accurately in a shcramjet inlet. Substituting the second inlet shock by a Prandtl-Meyer compression fan is encouraged as it decreases the thrust potential losses, reduces the risk of premature ignition by reducing the static temperature, while decreasing the mixing efficiency by a mere 6%. One approach that is observed herein to be successful at increasing the mixing efficiency in the inlet is by alternating the injection angle along the injector array. The use of two injection angles of 9 and 16 degrees is seen to result in a 32% increase in the mixing efficiency at

Investigation in the Langley 19-foot Pressure Tunnel of Two Wings of NACA 65-210 and 64-210 Airfoil Sections with Various Type Flaps

NASA Technical Reports Server (NTRS)

Sivells, James C; Spooner, Stanley H

1949-01-01

Report presents the results of an investigation conducted in the Langley 19-foot pressure tunnel to determine the maximum lift and stalling characteristics of two thin wings equipped with several types of flaps. Split, single slotted, and double slotted flaps were tested on one wing which had NACA 65-210 airfoil sections and split and double slotted flaps were tested on the other, which had NACA 64-210 airfoil sections. Both wings were zero sweep, an aspect ratio of 9, and a taper ratio of 0.4.

Effect of Surface Roughness on Characteristics of Aerofoils N.A.C.A. 0012 and R.A.F. 34

DTIC Science & Technology

1936-02-13

TABLE 3 N.A.C.A. 0012. Hand finished R x 10-« 0-164 0-312 0-63 0-98 1-44 1-47J 1-99 302 3-94 5- 52 ’ 7-20 i P. atmos. 1 1 21 j 3-6 4-8...Roughened FF R x ’.0-* 0-308 103 201 311 5- 52 P. a>.::ios. 1 3-9 7-9 11 -6 18-3 V.f./s 76-2 65-4 63-7 67-8 79-2 TABLE 6 N.A.C.A. 0012. Chromium...4 70-5 78-9 781 TABLE 7 R.A.F. 34. Hand finished R x 10-« 0-31 i 1 25 2-56 3- 52 4 51 5-47 6-47 2- 52 2- 52 7-17 I*. atmos. I 4-3 8-3 13-2 14-7

14 CFR 25.941 - Inlet, engine, and exhaust compatibility.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., engine, and exhaust compatibility. For airplanes using variable inlet or exhaust system geometry, or both— (a) The system comprised of the inlet, engine (including thrust augmentation systems, if incorporated... configurations; (b) The dynamic effects of the operation of these (including consideration of probable...

The Total-Pressure Recovery and Drag Characteristics of Several Auxiliary Inlets at Transonic Speeds

NASA Technical Reports Server (NTRS)

Dennard, John S.

1959-01-01

Several flush and scoop-type auxiliary inlets have been tested for a range of Mach numbers from 0.55 to 1.3 to determine their transonic total-pressure recovery and drag characteristics. The inlet dimensions were comparable with the thickness of the boundary layer in which they were tested. Results indicate that flush inlets should be inclined at very shallow angles with respect to the surface for optimum total-pressure recovery and drag characteristics. Deep, narrow inlets have lower drag than wide shallow ones at Mach numbers greater than 0.9 but at lower Mach numbers the wider inlets proved superior. Inlets with a shallow approach ramp, 7 deg, and diverging ramp walls which incorporated boundary-layer bypass had lower drag than any other inlet tested for Mach numbers up to 1.2 and had the highest pressure recovery of all of the flush inlets. The scoop inlets, which operated in a higher velocity flow than the flush inlets, had higher drag coefficients. Several of these auxiliary inlets projected multiple, periodic shock waves into the stream when they were operated at low mass-flow ratios.

Ultra high bypass Nacelle aerodynamics inlet flow-through high angle of attack distortion test

NASA Technical Reports Server (NTRS)

Larkin, Michael J.; Schweiger, Paul S.

1992-01-01

A flow-through inlet test program was conducted to evaluate inlet test methods and determine the impact of the fan on inlet separation when operating at large angles of attack. A total of 16 model configurations of approximately 1/6 scale were tested. A comparison of these flow-through results with powered data indicates the presence of the fan increased separation operation 3 degrees to 4 degrees over the flow through inlet. Rods and screens located at the fan face station, that redistribute the flow, achieved simulation of the powered-fan results for separation angle of attack. Concepts to reduce inlet distortion and increase angle of attack capability were also evaluated. Vortex generators located on the inlet surface increased inlet angle of attack capability up to 2 degrees and reduced inlet distortion in the separated region. Finally, a method of simulating the fan/inlet aerodynamic interaction using blockage sizing method has been defined. With this method, a static blockage device used with a flow-through model will approximate the same inlet onset of separation angle of attack and distortion pattern that would be obtained with an inlet model containing a powered fan.

8. View southwest at the northeastern end of culvert inlet, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. View southwest at the northeastern end of culvert inlet, with canal bank completely removed. Left to right: back of curved wingwall; tops of high inlet barrels; vertical transition wall between high inlet barrels and low interior barrels; tops of low, interior barrels; vertical heartening planks at former canal edge of canal bank. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

Calculation of external-internal flow fields for mixed-compression inlets

NASA Technical Reports Server (NTRS)

Chyu, W. J.; Kawamura, T.; Bencze, D. P.

1986-01-01

Supersonic inlet flows with mixed external-internal compressions were computed using a combined implicit-explicit (Beam-Warming-Steger/MacCormack) method for solving the three-dimensional unsteady, compressible Navier-Stokes equations in conservation form. Numerical calculations were made of various flows related to such inlet operations as the shock-wave intersections, subsonic spillage around the cowl lip, and inlet started versus unstarted conditions. Some of the computed results were compared with wind tunnel data.

Calculation of external-internal flow fields for mixed-compression inlets

NASA Technical Reports Server (NTRS)

Chyu, W. J.; Kawamura, T.; Bencze, D. P.

1987-01-01

Supersonic inlet flows with mixed external-internal compressions were computed using a combined implicit-explicit (Beam-Warming-Steger/MacCormack) method for solving the three-dimensional unsteady, compressible Navier-Stokes equations in conservation form. Numerical calculations were made of various flows related to such inlet operations as the shock-wave intersections, subsonic spillage around the cowl lip, and inlet started versus unstarted conditions. Some of the computed results were compared with wind tunnel data.

Submerged flow bridge scour under clear water conditions

DOT National Transportation Integrated Search

2012-09-01

Prediction of pressure flow (vertical contraction) scour underneath a partially or fully submerged bridge superstructure : in an extreme flood event is crucial for bridge safety. An experimentally and numerically calibrated formulation is : developed...

Evaluation of Flush-Mounted, S-Duct Inlets with Large Amounts of Boundary Layer Ingestion

NASA Technical Reports Server (NTRS)

Berrier, Bobby L.; Morehouse, Melissa B.

2003-01-01

A new high Reynolds number test capability for boundary layer ingesting inlets has been developed for the NASA Langley Research Center 0.3-Meter Transonic Cryogenic Tunnel. Using this new capability, an experimental investigation of four S-duct inlet configurations with large amounts of boundary layer ingestion (nominal boundary layer thickness of about 40% of inlet height) was conducted at realistic operating conditions (high subsonic Mach numbers and full-scale Reynolds numbers). The objectives of this investigation were to 1) provide a database for CFD tool validation on boundary layer ingesting inlets operating at realistic conditions and 2) provide a baseline inlet for future inlet flow-control studies. Tests were conducted at Mach numbers from 0.25 to 0.83, Reynolds numbers (based on duct exit diameter) from 5.1 million to a full-scale value of 13.9 million, and inlet mass-flow ratios from 0.39 to 1.58 depending on Mach number. Results of this investigation indicate that inlet pressure recovery generally decreased and inlet distortion generally increased with increasing Mach number. Except at low Mach numbers, increasing inlet mass-flow increased pressure recovery and increased distortion. Increasing the amount of boundary layer ingestion (by decreasing inlet throat height) or ingesting a boundary layer with a distorted (adverse) profile decreased pressure recovery and increased distortion. Finally, increasing Reynolds number had almost no effect on inlet distortion but increased inlet recovery by about one-half percent at a Mach number near cruise.

Inverse design of centrifugal compressor vaned diffusers in inlet shear flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zangeneh, M.

1996-04-01

A three-dimensional inverse design method in which the blade (or vane) geometry is designed for specified distributions of circulation and blade thickness is applied to the design of centrifugal compressor vaned diffusers. Two generic diffusers are designed, one with uniform inlet flow (equivalent to a conventional design) and the other with a sheared inlet flow. The inlet shear flow effects are modeled in the design method by using the so-called ``Secondary Flow Approximation`` in which the Bernoulli surfaces are convected by the tangentially mean inviscid flow field. The difference between the vane geometry of the uniform inlet flow and nonuniformmore » inlet flow diffusers is found to be most significant from 50 percent chord to the trailing edge region. The flows through both diffusers are computed by using Denton`s three-dimensional inviscid Euler solver and Dawes` three-dimensional Navier-Stokes solver under sheared in-flow conditions. The predictions indicate improved pressure recovery and internal flow field for the diffuser designed for shear inlet flow conditions.« less

Durability performance of submerged concrete structures - phase 2.

DOT National Transportation Integrated Search

2015-09-01

This project determined that severe corrosion of steel can occur in the submerged : portions of reinforced concrete structures in marine environments. Field studies of decommissioned : pilings from Florida bridges revealed multiple instances of stron...

Aerodynamic and acoustic behavior of a YF-12 inlet at static conditions

NASA Technical Reports Server (NTRS)

Bangert, L. H.; Feltz, E. P.; Godby, L. A.; Miller, L. D.

1981-01-01

An aeroacoustic test program to determine the cause of YF-12 inlet noise suppression was performed with a YF-12 aircraft at ground static conditions. Data obtained over a wide range of engine speeds and inlet configurations are reported. Acoustic measurements were made in the far field and aerodynamic and acoustic measurements were made inside the inlet. The J-58 test engine was removed from the aircraft and tested separately with a bellmouth inlet. The far field noise level was significantly lower for the YF-12 inlet than for the bellmouth inlet at engine speeds above 5500 rpm. There was no evidence that noise suppression was caused by flow choking. Multiple pure tones were reduced and the spectral peak near the blade passing frequency disappeared in the region of the spike support struts at engine speeds between 6000 and 6600 rpm.

Computational Fluid Dynamics (CFD) Investigation of Submerged Combustion Behavior in a Tuyere Blown Slag-fuming Furnace

NASA Astrophysics Data System (ADS)

Huda, Nazmul; Naser, Jamal; Brooks, G. A.; Reuter, M. A.; Matusewicz, R. W.

2012-10-01

A thin-slice computational fluid dynamics (CFD) model of a conventional tuyere blown slag-fuming furnace has been developed in Eulerian multiphase flow approach by employing a three-dimensional (3-D) hybrid unstructured orthographic grid system. The model considers a thin slice of the conventional tuyere blown slag-fuming furnace to investigate details of fluid flow, submerged coal combustion dynamics, coal use behavior, jet penetration behavior, bath interaction conditions, and generation of turbulence in the bath. The model was developed by coupling the CFD with the kinetics equations developed by Richards et al. for a zinc-fuming furnace. The model integrates submerged coal combustion at the tuyere tip and chemical reactions with the heat, mass, and momentum interfacial interaction between the phases present in the system. A commercial CFD package AVL Fire 2009.2 (AVL, Graz, Austria) coupled with several user-defined subroutines in FORTRAN programming language were used to develop the model. The model predicted the velocity, temperature field of the molten slag bath, generated turbulence and vortex, and coal use behavior from the slag bath. The tuyere jet penetration length ( l P) was compared with the equation provided by Hoefele and Brimacombe from isothermal experimental work ( {{l_{{P}} }/{d_{o }} = 10.7( {N^' }_{Fr} } )^{0.46} ( {ρ_{{g}} /ρl } )^{0.35} } ) and found 2.26 times higher, which can be attributed to coal combustion and gas expansion at a high temperature. The jet expansion angle measured for the slag system studied is 85 deg for the specific inlet conditions during the simulation time studied. The highest coal penetration distance was found to be l/L = 0.2, where l is the distance from the tuyere tip along the center line and L is the total length (2.44 m) of the modeled furnace. The model also predicted that 10 pct of the injected coal bypasses the tuyere gas stream uncombusted and carried to the free surface by the tuyere gas stream, which

Effects of inlet distortion on the development of secondary flows in a subsonic axial inlet compressor rotor. Ph.D. Thesis - Toledo Univ., OH

NASA Technical Reports Server (NTRS)

Owen, Albert K.

1991-01-01

Detailed flow measurements were taken inside an isolated axial compressor rotor operating subsonically near peak efficiency. Laser anemometer measurements were made with two inlet velocity profiles. One profile consisted of an unmodified baseline flow, and the second profile was distorted by placing axisymmetric screens on the hub and shroud well upstream of the rotor. A primary flow is defined in the rotor and deviations from this primary flow for each inlet flow condition identified. A comparison between the two flow deviations is made to assess the development of a passage vortex due to the distortion of the inlet flow. A comparison of experimental results with computational predictions from a Navier-Stokes solver showed good agreement between predicted and measured flow. Measured results indicate that a distorted inlet profile has minimal effect on the development of the flow in the rotor passage and the resulting passage vortex.

Inlet nozzle assembly

DOEpatents

Christiansen, David W.; Karnesky, Richard A.; Precechtel, Donald R.; Smith, Bob G.; Knight, Ronald C.

1987-01-01

An inlet nozzle assembly for directing coolant into the duct tube of a fuel assembly attached thereto. The nozzle assembly includes a shell for housing separable components including an orifice plate assembly, a neutron shield block, a neutron shield plug, and a diffuser block. The orifice plate assembly includes a plurality of stacked plates of differently configurated and sized openings for directing coolant therethrough in a predesigned flow pattern.

Inlet nozzle assembly

DOEpatents

Christiansen, D.W.; Karnesky, R.A.; Knight, R.C.; Precechtel, D.R.; Smith, B.G.

1985-09-09

An inlet nozzle assembly for directing coolant into the duct tube of a fuel assembly attached thereto. The nozzle assembly includes a shell for housing separable components including an orifice plate assembly, a neutron shield block, a neutron shield plug, and a diffuser block. The orifice plate assembly includes a plurality of stacked plates of differently configurated and sized openings for directing coolant therethrough in a predesigned flow pattern.

Boundary-Layer Transition on the N.A.C.A. 0012 and 23012 Airfoils in the 8-Foot High-Speed Wind Tunnel, Special Report

NASA Technical Reports Server (NTRS)

Becker, John V.

1940-01-01

Determinations of boundary-layer transition on the NACA 0012 and 2301 airfoils were made in the 8-foot high-speed wind tunnel over a range of Reynolds Numbers from 1,600,000 to 16,800,000. The results are of particular significance as compared with flight tests and tests in wind tunnels of appreciable turbulence because of the extremely low turbulence in the high-speed tunnel. A comparison of the results obtained on NACA 0012 airfoils of 2-foot and 5-foot chord at the same Reynolds Number permitted an evaluation of the effect of compressibility on transition. The local skin friction along the surface of the NACA 0012 airfoil was measured at a Reynolds Number of 10,000,000. For all the lift coefficient at which tests were made, transition occurred in the region of estimated laminar separation at the low Reynolds Numbers and approach the point of minimum static pressure as a forward limit at the high Reynolds Numbers. The effect of compressibility on transition was slight. None of the usual parameters describing the local conditions in the boundary layer near the transition point served as an index for locating the transition point. As a consequence of the lower turbulence in the 8-foot high-speed tunnel, the transition points occurred consistently farther back along the chord than those measured in the NACA full-scale tunnel. An empirical relation for estimating the location of the transition point for conventional airfoils on the basis of static-pressure distribution and Reynolds Number is presented.

Improving commercial broiler attic inlet ventilation thorugh CFD analysis

USDA-ARS?s Scientific Manuscript database

The use of solar heated attic air is an area of increasing interest in commercial poultry production. Attic inlets satisfy the demand for alternative heating while being simple to implement in an existing poultry house. A number of demonstration projects have suggested that attic inlets may decrease...

Passive acoustic monitoring of Cook Inlet beluga whales (Delphinapterus leucas).

PubMed

Lammers, Marc O; Castellote, Manuel; Small, Robert J; Atkinson, Shannon; Jenniges, Justin; Rosinski, Anne; Oswald, Julie N; Garner, Chris

2013-09-01

The endangered beluga whale (Delphinapterus leucas) population in Cook Inlet, AK faces threats from a variety of anthropogenic factors, including coastal development, oil and gas exploration, vessel traffic, and military activities. To address existing gaps in understanding about the occurrence of belugas in Cook Inlet, a project was developed to use passive acoustic monitoring to document the year-round distribution of belugas, as well as killer whales (Orcinus orca), which prey on belugas. Beginning in June 2009, ten moorings were deployed throughout the Inlet and refurbished every two to eight months. Despite challenging conditions consisting of strong tidal currents carrying debris and seasonal ice cover, 83% of mooring deployments were successfully recovered. Noise from water flow, vessel traffic, and/or industrial activities was present at several sites, potentially masking some signals. However, belugas were successfully detected at multiple locations. Detections were relatively common in the upper inlet and less common or absent at middle and lower inlet locations. Killer whale signals were also recorded. Some seasonal variability in the occurrence of both belugas and killer whales was evident.

Submerged beachrock preservation in the context of wave ravinement

NASA Astrophysics Data System (ADS)

Pretorius, Lauren; Green, Andrew N.; Andrew Cooper, J.

2018-02-01

This study examines a Holocene-aged submerged shoreline, Limestone Reef, located in the shallow subtidal zone of South Africa's east coast. It comprises an elongate, coast-oblique, slab-like outcrop of beachrock situated above the contemporary fair-weather wave base. It is currently undergoing mechanical disintegration. Its unique and rare preservation in a high-energy setting affords an opportunity to examine the mechanical processes occurring during wave ravinement associated with rising sea level. The submerged shoreline and the adjacent shoreface were examined using high-resolution seismic reflection, side-scan sonar and shallow-water multibeam echosounding techniques. Limestone Reef rests on top of unconsolidated Holocene deposits. The structure's surface is characterised by reef-perpendicular gullies with rubble derived from the slab fringing its seaward edge. Limestone Reef slopes gently seawards and has a steep landward-facing edge where gullies are most prominently developed. Teardrop-shaped rippled scour depressions, marked by high backscatter, are located seawards of the submerged shoreline. These elongate in a seaward direction and are filled with bioclastic gravels and residual rubble from Limestone Reef. The gullies in the upstanding structure are indicative of wave plucking and abrasion of the shoreline. The material exposed by the rippled scour depressions is identical to that comprising the postglacial ravinement surface identified in the offshore stratigraphy. These deposits are considered to represent the contemporary, actively forming wave ravinement surface. The results suggest that wave ravinement of submerged shorelines is a discontinuous process dominated by the seaward entrainment of material from its landward edge controlled by high-energy drawback during storm surges. The ravinement process appears to operate at the seasonal scale and averages out over the long-term millennial scale for the continuous surface.

Investigation of "6X" Scramjet Inlet Configurations

NASA Technical Reports Server (NTRS)

Alter, Stephen J.

2012-01-01

This work represents an initial attempt to determine what, if any, issues arise from scaling demonstration supersonic combustion scramjets to a flight scale making the engine a viable candidate for both military weapon and civilian access to space applications. The original vehicle sizes tested and flown to date, were designed to prove a concept. With the proven designs, use of the technology for applications as weapon systems or space flight are only possible at six to ten times the original scale. To determine effects of scaling, computations were performed with hypersonic inlets designed to operate a nominal Mach 4 and Mach 5 conditions that are possible within the eight foot high temperature tunnel at NASA Langley Research Center. The total pressure recovery for these inlets is about 70%, while maintaining self start conditions, and providing operable inflow to combustors. Based on this study, the primary scaling effect detected is the strength of a vortex created along the cowl edge causing adverse boundary layer growth in the inlet.

Forebody and Inlet Design for the HIFiRE 2 Flight Test

NASA Technical Reports Server (NTRS)

Ferlemann, Paul G.

2008-01-01

A forebody and inlet have been designed for the HIFiRE 2 scramjet flight test. The test will explore the operating, performance, and stability characteristics of a simple hydrocarbon-fueled scramjet combustor as it transitions from dual-mode to scramjet-mode operation and during supersonic combustion at Mach 8+ flight conditions. Requirements for the compression system were derived from inlet starting and combustor inflow requirements as well as physical size constraints. The design process is described. A planar, fixed geometry, mixed compression concept was used to produce laterally uniform flow at the inlet entrance and a conservative amount of internal contraction with respect to inlet starting. A grid sensitivity study was performed so that important flow physics caused by three-dimensional shock boundary layer interactions could be captured with confidence. Results from low Mach number operability studies, nominal trajectory cases, and high dynamic pressure heat load cases are discussed. The forebody and inlet solutions provide information for on-going combustor calculations, mass capture across the trajectory for fuel system design, and surface heating rates for thermal/structural analysis. The design has a one freestream Mach number margin for inlet starting, exceeds the high Mach number combustor entrance pressure requirement, produces high quality flow at the inlet exit for all Mach numbers and vehicle attitudes in the design space, and fits inside the booster shroud.

Effect of a dual inlet channel on cell loading in microfluidics.

PubMed

Yun, Hoyoung; Kim, Kisoo; Lee, Won Gu

2014-11-01

Unwanted sedimentation and attachment of a number of cells onto the bottom channel often occur on relatively large-scale inlets of conventional microfluidic channels as a result of gravity and fluid shear. Phenomena such as sedimentation have become recognized problems that can be overcome by performing microfluidic experiments properly, such as by calculating a meaningful output efficiency with respect to real input. Here, we present a dual-inlet design method for reducing cell loss at the inlet of channels by adding a new " upstream inlet " to a single main inlet design. The simple addition of an upstream inlet can create a vertically layered sheath flow prior to the main inlet for cell loading. The bottom layer flow plays a critical role in preventing the cells from attaching to the bottom of the channel entrance, resulting in a low possibility of cell sedimentation at the main channel entrance. To provide proof-of-concept validation, we applied our design to a microfabricated flow cytometer system (μFCS) and compared the cell counting efficiency of the proposed μFCS with that of the previous single-inlet μFCS and conventional FCS. We used human white blood cells and fluorescent microspheres to quantitatively evaluate the rate of cell sedimentation in the main inlet and to measure fluorescence sensitivity at the detection zone of the flow cytometer microchip. Generating a sheath flow as the bottom layer was meaningfully used to reduce the depth of field as well as the relative deviation of targets in the z-direction (compared to the x-y flow plane), leading to an increased counting sensitivity of fluorescent detection signals. Counting results using fluorescent microspheres showed both a 40% reduction in the rate of sedimentation and a 2-fold higher sensitivity in comparison with the single-inlet μFCS. The results of CD4(+) T-cell counting also showed that the proposed design results in a 25% decrease in the rate of cell sedimentation and a 28% increase in

Application of CFD to the analysis and design of high-speed inlets

NASA Technical Reports Server (NTRS)

Rose, William C.

1995-01-01

Over the past seven years, efforts under the present Grant have been aimed at being able to apply modern Computational Fluid Dynamics to the design of high-speed engine inlets. In this report, a review of previous design capabilities (prior to the advent of functioning CFD) was presented and the example of the NASA 'Mach 5 inlet' design was given as the premier example of the historical approach to inlet design. The philosophy used in the Mach 5 inlet design was carried forward in the present study, in which CFD was used to design a new Mach 10 inlet. An example of an inlet redesign was also shown. These latter efforts were carried out using today's state-of-the-art, full computational fluid dynamics codes applied in an iterative man-in-the-loop technique. The potential usefulness of an automated machine design capability using an optimizer code was also discussed.

Background-Oriented Schlieren used in a hypersonic inlet test at NASA GRC

NASA Technical Reports Server (NTRS)

Clem, Michelle; Woike, Mark; Saunders, John

2016-01-01

Background Oriented Schlieren (BOS) is a derivative of the classical schlieren technology, which is used to visualize density gradients, such as shock wave structures in a wind tunnel. Changes in refractive index resulting from density gradients cause light rays to bend, resulting in apparent motion of a random background pattern. The apparent motion of the pattern is determined using cross-correlation algorithms (between no-flow and with-flow image pairs) producing a schlieren-like image. One advantage of BOS is its simplified setup which enables a larger field-of-view (FOV) than traditional schlieren systems. In the present study, BOS was implemented into the Combined Cycle Engine Large-Scale Inlet Mode Transition Experiment (CCE LIMX) in the 10x10 Supersonic Wind Tunnel at NASA Glenn Research Center. The model hardware for the CCE LIMX accommodates a fully integrated turbine based combined cycle propulsion system. To date, inlet mode transition between turbine and ramjet operation has been successfully demonstrated. High-speed BOS was used to visualize the behavior of the flow structures shock waves during unsteady inlet unstarts, a phenomenon known as buzz. Transient video images of inlet buzz were recorded for both the ramjet flow path (high speed inlet) and turbine flow path (low speed inlet). To understand the stability limits of the inlet, operation was pushed to the point of unstart and buzz. BOS was implemented in order to view both inlets simultaneously, since the required FOV was beyond the capability of the current traditional schlieren system. An example of BOS data (Images 1-6) capturing inlet buzz are presented.

Tidal and subtidal exchange flows at an inlet of the Wadden Sea

NASA Astrophysics Data System (ADS)

Valle-Levinson, Arnoldo; Stanev, Emil; Badewien, Thomas H.

2018-03-01

Observations of underway velocity profiles during complete spring and neap tidal cycles were used to determine whether the spatial structures of tidal and subtidal flows at a tidal inlet in a multiple-inlet embayment are consistent with those observed at single-inlet embayments. Measurements were obtained at the Otzumer Balje, one of the multiple inlets among the East Frisian Islands of the Wadden Sea. The 1.5 km-wide inlet displayed a bathymetric profile consisting of a channel ∼15 m deep flanked by <5 m shoals. Neap tide observations spanned 36 h in the period May 11-12, 2011, while spring tide measurements exceeded 48 h from May 17 to May 19, 2011. Analysis of observations indicate that frictional effects from bathymetry molded tidal flows. Spatial distributions of semidiurnal tidal current amplitude and phase conform to those predicted by an analytical model for a basin with one inlet. Maximum semidiurnal flows appear at the surface in the channel, furthest away from bottom friction effects. Therefore, Otzumer Balje displays tidal hydrodynamics that are independent of the other inlets of the embayment. Subtidal exchange flows are laterally sheared, with residual inflow in the channel combined with outflow over shoals. The spatial distribution of these residual flows follow theoretical expectations of tidally driven flows interacting with bathymetry. Such distribution is similar to the tidal residual circulation at other inlets with only one communication to the ocean, suggesting that at subtidal scales the Otzumer Balje responds to tidal forcing independently of the other inlets.

33 CFR 110.170 - Lockwoods Folly Inlet, N.C.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lockwoods Folly Inlet, N.C. 110.170 Section 110.170 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.170 Lockwoods Folly Inlet, N.C. (a) Explosives...

33 CFR 110.170 - Lockwoods Folly Inlet, N.C.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lockwoods Folly Inlet, N.C. 110.170 Section 110.170 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.170 Lockwoods Folly Inlet, N.C. (a) Explosives...

40 CFR 91.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (b) The air inlet filter system and exhaust muffler system combination used on the test engine must... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine inlet and exhaust systems. 91.407 Section 91.407 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

Flow Control in a Compact Inlet

NASA Astrophysics Data System (ADS)

Vaccaro, John C.

2011-12-01

An experimental investigation of flow control, via various control jets actuators, was undertaken to eliminate separation and secondary flows in a compact inlet. The compact inlet studied was highly aggressive with a length-to-diameter ratio of 1.5. A brand new facility was designed and built to enable various actuation methodologies as well as multiple measurement techniques. Techniques included static surface pressure, total pressure, and stereoscopic particle image velocimetry. Experimental data were supplemented with numerical simulations courtesy of Prof. Kenneth Jansen, Dr. Onkar Sahni, and Yi Chen. The baseline flow field was found to be dominated by two massive separations and secondary flow structures. These secondary structures were present at the aerodynamic interface plane in the form of two counter-rotating vortices inducing upwash along centerline. A dominant shedding frequency of 350 Hz was measured both at the aerodynamic interface plane and along the lower surface of the inlet. Flow control experiments started utilizing a pair of control jets placed in streamwise locations where flow was found to separate. Tests were performed for a range of inlet Mach numbers from 0.2 to 0.44. Steady and unsteady static pressure measurements along the upper and lower walls of the duct were performed for various combinations of actuation. The parameters that were tested include the control jets momentum coefficient, their blowing ratio, the actuation frequency, as well as different combinations of jets. It was shown that using mass flux ratio as a criterion to define flow control is not sufficient, and one needs to provide both the momentum coefficient and the blowing ratio to quantify the flow control performance. A detailed study was undertaken on controlling the upstream separation point for an inlet Mach number of 0.44. Similar to the baseline flow field, the flow field associated with the activation of a two-dimensional control jet actuator was dominated by

Numerical simulation of supersonic inlets using a three-dimensional viscous flow analysis

NASA Technical Reports Server (NTRS)

Anderson, B. H.; Towne, C. E.

1980-01-01

A three dimensional fully viscous computer analysis was evaluated to determine its usefulness in the design of supersonic inlets. This procedure takes advantage of physical approximations to limit the high computer time and storage associated with complete Navier-Stokes solutions. Computed results are presented for a Mach 3.0 supersonic inlet with bleed and a Mach 7.4 hypersonic inlet. Good agreement was obtained between theory and data for both inlets. Results of a mesh sensitivity study are also shown.

Estimation of additive forces and moments for supersonic inlets

NASA Technical Reports Server (NTRS)

Perkins, Stanley C., Jr.; Dillenius, Marnix F. E.

1991-01-01

A technique for estimating the additive forces and moments associated with supersonic, external compression inlets as a function of mass flow ratio has been developed. The technique makes use of a low order supersonic paneling method for calculating minimum additive forces at maximum mass flow conditions. A linear relationship between the minimum additive forces and the maximum values for fully blocked flow is employed to obtain the additive forces at a specified mass flow ratio. The method is applicable to two-dimensional inlets at zero or nonzero angle of attack, and to axisymmetric inlets at zero angle of attack. Comparisons with limited available additive drag data indicate fair to good agreement.

33 CFR 334.1240 - Sinclair Inlet; naval restricted areas.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Sinclair Inlet; naval restricted...; naval restricted areas. (a) Sinclair Inlet: naval restricted areas—(1) Area No. 1. All the waters of... Navy. No person, vessel, craft, article or thing, except those under supervision of military or naval...

33 CFR 334.1240 - Sinclair Inlet; naval restricted areas.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Sinclair Inlet; naval restricted...; naval restricted areas. (a) Sinclair Inlet: naval restricted areas—(1) Area No. 1. All the waters of... Navy. No person, vessel, craft, article or thing, except those under supervision of military or naval...

Separation control of NACA0015 airfoil using plasma actuators

NASA Astrophysics Data System (ADS)

Harada, Daisuke; Sakakibara, Jun

2017-11-01

Separation control of NACA0015 airfoil by means of plasma actuators was investigated. Plasma actuators in spanwise intermittent layout on the suction surface of the airfoil were activated with spanwise phase difference φ = 0 or φ = π in the case of dimensionless burst frequencyF+ = 6 and F+ = 0.5 at Re = 6.3 ×104 . The lift and drag of the airfoil were measured using a two component force balance. The flow around the airfoil was measured by PIV analysis. In the condition of F+ = 6 and φ = π at around stall angle, which is 10 degrees, the lift-to-drag ratio was higher than that ofF+ = 6 and φ = 0 . Therefore, it was confirmed that aerodynamic characteristics of the airfoil improved by disturbances with temporal and spatial phase difference.

Submerged AUV Charging Station

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Chao, Yi; Curtin, Thomas

2014-01-01

Autonomous Underwater Vehicles (AUVs) are becoming increasingly important for military surveillance and mine detection. Most AUVs are battery powered and have limited lifetimes of a few days to a few weeks. This greatly limits the distance that AUVs can travel underwater. Using a series of submerged AUV charging stations, AUVs could travel a limited distance to the next charging station, recharge its batteries, and continue to the next charging station, thus traveling great distances in a relatively short time, similar to the Old West “Pony Express.” One solution is to use temperature differences at various depths in the ocean to produce electricity, which is then stored in a submerged battery. It is preferred to have the upper buoy submerged a reasonable distance below the surface, so as not to be seen from above and not to be inadvertently destroyed by storms or ocean going vessels. In a previous invention, a phase change material (PCM) is melted (expanded) at warm temperatures, for example, 15 °C, and frozen (contracted) at cooler temperatures, for example, 8 °C. Tubes containing the PCM, which could be paraffin such as pentadecane, would be inserted into a container filled with hydraulic oil. When the PCM is melted (expanded), it pushes the oil out into a container that is pressurized to about 3,000 psi (approx equals 20.7 MPa). When a valve is opened, the high-pressure oil passes through a hydraulic motor, which turns a generator and charges a battery. The low-pressure oil is finally reabsorbed into the PCM canister when the PCM tubes are frozen (contracted). Some of the electricity produced could be used to control an external bladder or a motor to the tether line, such that depth cycling is continued for a very long period of time. Alternatively, after the electricity is generated by the hydraulic motor, the exiting low-pressure oil from the hydraulic motor could be vented directly to an external bladder on the AUV, such that filling of the bladder

Crestal bone loss around submerged and nonsubmerged dental implants: A systematic review.

PubMed

Al Amri, Mohammad D

2016-05-01

To my knowledge, there is no systematic review of crestal bone loss (CBL) around submerged and nonsubmerged dental implants. The purpose of this review was to systematically assess CBL around submerged and nonsubmerged dental implants. The addressed focused question was, "Does crestal and subcrestal placement of dental implants influence crestal bone levels?" Databases were searched from 1986 through October 2015 using different combinations of the following keywords: crestal, sub-crestal, bone loss, dental implant, submerged, and nonsubmerged. Reference lists of potentially relevant original and review articles were hand-searched to identify any further studies. Letters to the editor, case reports, commentaries, studies on platform-switched implants, and studies published in languages other than English were excluded. In total, 13 studies (6 human and 7 animal), which were performed at universities, were included. In the human studies, the number of participants ranged from 8 to 84 individuals. The follow-up period ranged from 1 to 5 years. CBL at the test sites ranged from 0.17 mm to 0.9 mm and at control sites from 0.02 mm to 1.4 mm. Five human studies reported no significant difference in CBL around implants placed at the test and control sites. All animal studies were performed in dogs with a mean age ranging from 1 to approximately 2 years. The follow-up period ranged from 2 to 6 months. Four animal studies reported no significant difference in CBL around submerged and nonsubmerged implants. No significant difference in CBL was found around submerged and nonsubmerged dental implants. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Feasibility study of inlet shock stability system of YF-12

NASA Technical Reports Server (NTRS)

Blausey, G. C.; Coleman, D. M.; Harp, D. S.

1972-01-01

The feasibility of self actuating bleed valves as a shock stabilization system in the inlet of the YF-12 is considered for vortex valves, slide valves, and poppet valves. Analytical estimation of valve performance indicates that only the slide and poppet valves located in the inlet cowl can meet the desired steady state stabilizing flows, and of the two the poppet valve is substantially faster in response to dynamic disturbances. The poppet valve is, therefore, selected as the best shock stability system for the YF-12 inlet.

Prediction of sound radiation from different practical jet engine inlets

NASA Technical Reports Server (NTRS)

Zinn, B. T.; Meyer, W. L.

1981-01-01

Computer codes, capable of producing accurate results for nondimensional wave numbers (based on duct radius) of up to 20, were developed and used to generate results for various other inlet configurations. Both reflection coefficients and radiation patterns were calculated by the integral solution procedure for the following five inlet configurations: the NASA Langley Bellmouth, the NASA Lewis JT-15D-1 ground test nacelle, and three hyperbolic inlets of 50, 70, and 90 degrees. Results obtained are compared with results from other experimental and theoretical studies.

Can submerged macrophytes influence turbidity and trophic state in deep lakes? Suggestions from a case study.

PubMed

Hilt, Sabine; Henschke, Ingo; Rücker, Jacqueline; Nixdorf, Brigitte

2010-01-01

Feedback between submerged macrophytes and water transparency stabilizing the clear, macrophyte-dominated regime has been described so far for shallow lakes. Based on data of total phosphorus (TP) concentrations, underwater light supply, phytoplankton and submerged macrophyte abundance from narrow, stratified Lake Scharmützelsee (mean depth: 9 m, retention time: 16 yr) of the period 1994-2006 we hypothesize that submerged macrophytes may influence transparency and trophic state in deep lakes. The lake was characterized by summer epilimnion TP concentrations of 38 to 57 mug L(-1), turbid water due to mass development of cyanobacteria, and low abundance of few submerged macrophyte species until 2003. Thereafter, a sudden increase in water transparency was followed by a rapid submerged macrophyte colonization of the littoral down to about 5 m depth corresponding to the depth of a light supply of 3 E m(-2) d(-1). Initially, this recolonization was probably a consequence of decreased turbidity. We argue that the increase of submerged macrophyte coverage from < 10% in 1994 to 2003 to about 24% in 2005-2006 has contributed to the stabilization of the clear-water regime during the subsequent years. This is supported by the fact that earlier shifts to clear-water regimes in 1994 and 2000 without a significant spread of submerged macrophytes were not stable. We discuss potential mechanisms that may have resulted in a positive effect of plants on transparency such as P uptake and immobilization by the dominant rootless macrophyte species Nitellopsis obtusa and Ceratophyllum demersum and other macrophyte-related mechanisms such as increased zooplankton grazing and allelopathy.

Submerged karst landforms observed by multibeam bathymetric survey in Nagura Bay, Ishigaki Island, southwestern Japan

NASA Astrophysics Data System (ADS)

Kan, Hironobu; Urata, Kensaku; Nagao, Masayuki; Hori, Nobuyuki; Fujita, Kazuhiko; Yokoyama, Yusuke; Nakashima, Yosuke; Ohashi, Tomoya; Goto, Kazuhisa; Suzuki, Atsushi

2015-01-01

Submerged tropical karst features were discovered in Nagura Bay on Ishigaki Island in the southern Ryukyu Islands, Japan. The coastal seafloor at depths shallower than ~ 130 m has been subjected to repeated and alternating subaerial erosion and sedimentation during periods of Quaternary sea-level lowstands. We conducted a broadband multibeam survey in the central area of Nagura Bay (1.85 × 2.7 km) and visualized the high-resolution bathymetric results over a depth range of 1.6-58.5 m. Various types of humid tropical karst landforms were found to coexist within the bay, including fluviokarst, doline karst, cockpit karst, polygonal karst, uvalas, and mega-dolines. Although these submerged karst landforms are covered by thick postglacial reef and reef sediments, their shapes and sizes are distinct from those associated with coral reef geomorphology. The submerged landscape of Nagura Bay likely formed during multiple glacial and interglacial periods. According to our bathymetric results and the aerial photographs of the coastal area, this submerged karst landscape appears to have developed throughout Nagura Bay (i.e., over an area of approximately 6 × 5 km) and represents the largest submerged karst in Japan.

NACA Computers Take Readings From Manometer Boards

NASA Image and Video Library

1949-02-21

Female computers at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory copy pressure readings from rows of manometers below the 18- by 18-inch Supersonic Wind Tunnel. The computers obtained test data from the manometers and other instruments, made the initial computations, and plotted the information graphically. Based on these computations, the researchers planned their next test or summarized their findings in a report. Manometers were mercury-filled glass tubes that were used to indicate different pressure levels from inside the test facility or from the test article. Manometers look and function very similarly to thermometers. Dozens of pressure sensing instruments were installed for each test. Each was connected to a manometer tube located inside the control room. The mercury inside the manometer rose and fell with the pressure levels. The dark mercury can be seen in this photograph at different levels within the tubes. Since this activity was dynamic, it was necessary to note the levels at given points during the test. This was done using both computer notations and photography.

5. View northwest at the northeastmost arch of culvert inlet ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. View northwest at the northeastmost arch of culvert inlet headwall, showing high inlet vault and interior drop arch. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

Management process invaded Ames as the Center shifted from NACA to NASA oversight. Ames constructed

NASA Technical Reports Server (NTRS)

1968-01-01

Management process invaded Ames as the Center shifted from NACA to NASA oversight. Ames constructed a review room in its headquarters building where, in the graphical style that prevailed in the 1960's, Ames leadership could review progress against schedule, budget and performance measures. Shown, in October 1965 is Merrill Mead chief of Ames' program and resources office. (for H Julian Allen Retirement album)

Deep Coastal Marine Taphonomy: Investigation into Carcass Decomposition in the Saanich Inlet, British Columbia Using a Baited Camera

PubMed Central

Anderson, Gail S.; Bell, Lynne S.

2014-01-01

Decomposition and faunal colonization of a carcass in the terrestrial environment has been well studied, but knowledge of decomposition in the marine environment is based almost entirely on anecdotal reports. Three pig carcasses were deployed in Saanich Inlet, BC, over 3 years utilizing Ocean Network Canada’s VENUS observatory. Each carcass was deployed in late summer/early fall at 99 m under a remotely controlled camera and observed several times a day. Dissolved oxygen, temperature, salinity, density and pressure were continuously measured. Carcass 1 was immediately colonized by Munida quadrispina, Pandalus platyceros and Metacarcinus magister, rapidly scavenged then dragged from view by Day 22. Artifacts specific to each of the crustaceans’ feeding patterns were observed. Carcass 2 was scavenged in a similar fashion. Exposed tissue became covered by Orchomenella obtusa (Family Lysianassidae) which removed all the internal tissues rapidly. Carcass 3 attracted only a few M. quadrispina, remaining intact, developing a thick filamentous sulphur bacterial mat, until Day 92, when it was skeletonized by crustacea. The major difference between the deployments was dissolved oxygen levels. The first two carcasses were placed when oxygen levels were tolerable, becoming more anoxic. This allowed larger crustacea to feed. However, Carcass 3 was deployed when the water was already extremely anoxic, which prevented larger crustacea from accessing the carcass. The smaller M. quadrispina were unable to break the skin alone. The larger crustacea returned when the Inlet was re-oxygenated in spring. Oxygen levels, therefore, drive the biota in this area, although most crustacea endured stressful levels of oxygen to access the carcasses for much of the time. These data will be valuable in forensic investigations involving submerged bodies, indicating types of water conditions to which the body has been exposed, identifying post-mortem artifacts and providing realistic

Axisymmetric Calculations of a Low-Boom Inlet in a Supersonic Wind Tunnel

NASA Technical Reports Server (NTRS)

Chima, Rodrick V.; Hirt, Stefanie M.; Reger, Robert

2011-01-01

This paper describes axisymmetric CFD predictions made of a supersonic low-boom inlet with a facility diffuser, cold pipe, and mass flow plug within wind tunnel walls, and compares the CFD calculations with the experimental data. The inlet was designed for use on a small supersonic aircraft that would cruise at Mach 1.6, with a Mach number over the wing of 1.7. The inlet was tested in the 8-ft by 6-ft Supersonic Wind Tunnel at NASA Glenn Research Center in the fall of 2010 to demonstrate the performance and stability of a practical flight design that included a novel bypass duct. The inlet design is discussed here briefly. Prior to the test, CFD calculations were made to predict the performance of the inlet and its associated wind tunnel hardware, and to estimate flow areas needed to throttle the inlet. The calculations were done with the Wind-US CFD code and are described in detail. After the test, comparisons were made between computed and measured shock patterns, total pressure recoveries, and centerline pressures. The results showed that the dual-stream inlet had excellent performance, with capture ratios near one, a peak core total pressure recovery of 96 percent, and a large stable operating range. Predicted core recovery agreed well with the experiment but predicted bypass recovery and maximum capture ratio were high. Calculations of offdesign performance of the inlet along a flight profile agreed well with measurements and previous calculations.

Physics of Acoustic Radiation from Jet Engine Inlets

NASA Technical Reports Server (NTRS)

Tam, Christopher K. W.; Parrish, Sarah A.; Envia, Edmane; Chien, Eugene W.

2012-01-01

Numerical simulations of acoustic radiation from a jet engine inlet are performed using advanced computational aeroacoustics (CAA) algorithms and high-quality numerical boundary treatments. As a model of modern commercial jet engine inlets, the inlet geometry of the NASA Source Diagnostic Test (SDT) is used. Fan noise consists of tones and broadband sound. This investigation considers the radiation of tones associated with upstream propagating duct modes. The primary objective is to identify the dominant physical processes that determine the directivity of the radiated sound. Two such processes have been identified. They are acoustic diffraction and refraction. Diffraction is the natural tendency for an acoustic wave to follow a curved solid surface as it propagates. Refraction is the turning of the direction of propagation of sound waves by mean flow gradients. Parametric studies on the changes in the directivity of radiated sound due to variations in forward flight Mach number and duct mode frequency, azimuthal mode number, and radial mode number are carried out. It is found there is a significant difference in directivity for the radiation of the same duct mode from an engine inlet when operating in static condition and in forward flight. It will be shown that the large change in directivity is the result of the combined effects of diffraction and refraction.

Potential and viscous flow in VTOL, STOL or CTOL propulsion system inlets

NASA Technical Reports Server (NTRS)

Stockman, N. O.

1975-01-01

A method was developed for analyzing the flow in subsonic axisymmetric inlets at arbitrary conditions of freestream velocity, incidence angle, and inlet mass flow. An improved version of the method is discussed and comparisons of results obtained with the original and improved methods are given. Comparisons with experiments are also presented for several inlet configurations and for various conditions of the boundary layer from insignificant to separated. Applications of the method are discussed, with several examples given for specific cases involving inlets for VTOL lift fans and for STOL engine nacelles.

Incidence angle bounds for lip flow separation of three 13.97-centimeter-diameter inlets

NASA Technical Reports Server (NTRS)

Luidens, R. W.; Abbott, J. M.

1976-01-01

Low speed wind tunnel tests were conducted to establish a procedure for determining inlet-lip flow separation and to make preliminary examination of the incidence angle bounds for lip flow separation on inlets intended for the nacelles of STOL (short takeoff and landing) aircraft. Three inlets were tested. Two of the inlets had short centerbodies with lower lip area contraction ratios of 1.30 and 1.44. The third inlet had a cylindrical centerbody extended forward into the inlet throat with a lower lip area contraction ratio of 1.44. The inlets were sized to fit a 13.97 centimeter-diameter fan. For inlet throat Mach numbers less than about 0.43, the lip flow separation angle was increased by either increasing the ratio of throat velocity to freestream velocity (Vt/Vo) or by increasing the lower lip area contraction ratio. For throat Mach numbers greater than a certain value (ranging from 0.43 to 0.52), increasing throat Mach number in some cases resulted in a decrease in the lip flow separation angle. Extending a cylindrical centerbody into the inlet throat increased the flow separation angle for nearly all values of Vt/Vo.

Orders of Magnitude: A History of NACA and NASA, 1915 - 1980

NASA Technical Reports Server (NTRS)

Anderson, F. W., Jr.

1981-01-01

The history of NACA and NASA from 1915 to 1980 is narrated. The impact of two world wars on aeronautics is reviewed. Research activity before and during World War II is presented. Postwar exploitation of new technologies is summarized. The creation of NASA and a comprehensive space program is discussed. Long range planning for a lunar mission is described. The Gemini project is reviewed. The Apollo project and side effects includng NASA's university and technology transfer programs are presented. Numerous scientific and application satellite projects are reviewed. The impact of budget reductions is explained. The value of space exploration is emphasized. Development of the Space Shuttle is reported.

Can barrier islands survive sea level rise? Tidal inlets versus storm overwash

NASA Astrophysics Data System (ADS)

Nienhuis, J.; Lorenzo-Trueba, J.

2017-12-01

Barrier island response to sea level rise depends on their ability to transgress and move sediment to the back barrier, either through flood-tidal delta deposition or via storm overwash. Our understanding of these processes over decadal to centennial timescales, however, is limited and poorly constrained. We have developed a new barrier inlet environment (BRIE) model to better understand the interplay between tidal dynamics, overwash fluxes, and sea-level rise on barrier evolution. The BRIE model combines existing overwash and shoreface formulations [Lorenzo-Trueba and Ashton, 2014] with alongshore sediment transport, inlet stability [Escoffier, 1940], inlet migration and flood-tidal delta deposition [Nienhuis and Ashton, 2016]. Within BRIE, inlets can open, close, migrate, merge with other inlets, and build flood-tidal delta deposits. The model accounts for feedbacks between overwash and inlets through their mutual dependence on barrier geometry. Model results suggest that when flood-tidal delta deposition is sufficiently large, barriers require less storm overwash to transgress and aggrade during sea level rise. In particular in micro-tidal environments with asymmetric wave climates and high alongshore sediment transport, tidal inlets are effective in depositing flood-tidal deltas and constitute the majority of the transgressive sediment flux. Additionally, we show that artificial inlet stabilization (via jetty construction or maintenance dredging) can make barrier islands more vulnerable to sea level rise. Escoffier, F. F. (1940), The Stability of Tidal Inlets, Shore and Beach, 8(4), 114-115. Lorenzo-Trueba, J., and A. D. Ashton (2014), Rollover, drowning, and discontinuous retreat: Distinct modes of barrier response to sea-level rise arising from a simple morphodynamic model, J. Geophys. Res. Earth Surf., 119(4), 779-801, doi:10.1002/2013JF002941. Nienhuis, J. H., and A. D. Ashton (2016), Mechanics and rates of tidal inlet migration: Modeling and application to

Submergence tolerance conferred by Sub1A is mediated by SLR1 and SLRL1 restriction of gibberellin responses in rice

PubMed Central

Fukao, Takeshi; Bailey-Serres, Julia

2008-01-01

Submergence-tolerant rice maintains viability during complete submergence by limiting underwater elongation until floodwaters recede. Acclimation responses to submergence are coordinated by the submergence-inducible Sub1A, which encodes an ethylene-responsive factor-type transcription factor (ERF). Sub1A is limited to tolerant genotypes and sufficient to confer submergence tolerance to intolerant accessions. Here we evaluated the role of Sub1A in the integration of ethylene, abscisic acid (ABA), and gibberellin (GA) signaling during submergence. The submergence-stimulated decrease in ABA content was Sub1A-independent, whereas GA-mediated underwater elongation was significantly restricted by Sub1A. Transgenics that ectopically express Sub1A displayed classical GA-insensitive phenotypes, leading to the hypothesis that Sub1A limits the response to GA. Notably Sub1A increased the accumulation of the GA signaling repressors Slender Rice-1 (SLR1) and SLR1 Like-1 (SLRL1) and concomitantly diminished GA-inducible gene expression under submerged conditions. In the Sub1A overexpression line, SLR1 protein levels declined under prolonged submergence but were accompanied by an increase in accumulation of SLRL1, which lacks the DELLA domain. In the presence of Sub1A, the increase in these GA signaling repressors and decrease in GA responsiveness were stimulated by ethylene, which promotes Sub1A expression. Conversely, ethylene promoted GA responsiveness and shoot elongation in submergence-intolerant lines. Together, these results demonstrate that Sub1A limits ethylene-promoted GA responsiveness during submergence by augmenting accumulation of the GA signaling repressors SLR1 and SLRL1. PMID:18936491

Contrasting submergence tolerance in two species of stem-succulent halophytes is not determined by differences in stem internal oxygen dynamics.

PubMed

Konnerup, Dennis; Moir-Barnetson, Louis; Pedersen, Ole; Veneklaas, Erik J; Colmer, Timothy D

2015-02-01

Many stem-succulent halophytes experience regular or episodic flooding events, which may compromise gas exchange and reduce survival rates. This study assesses submergence tolerance, gas exchange and tissue oxygen (O2) status of two stem-succulent halophytes with different stem diameters and from different elevations of an inland marsh. Responses to complete submergence in terms of stem internal O2 dynamics, photosynthesis and respiration were studied for the two halophytic stem-succulents Tecticornia auriculata and T. medusa. Plants were submerged in a glasshouse experiment for 3, 6 and 12 d and O2 levels within stems were measured with microelectrodes. Photosynthesis by stems in air after de-submergence was also measured. Tecticornia medusa showed 100 % survival in all submergence durations whereas T. auriculata did not survive longer than 6 d of submergence. O2 profiles and time traces showed that when submerged in water at air-equilibrium, the thicker stems of T. medusa were severely hypoxic (close to anoxic) when in darkness, whereas the smaller diameter stems of T. auriculata were moderately hypoxic. During light periods, underwater photosynthesis increased the internal O2 concentrations in the succulent stems of both species. Stems of T. auriculata temporally retained a gas film when first submerged, whereas T. medusa did not. The lower O2 in T. medusa than in T. auriculata when submerged in darkness was largely attributed to a less permeable epidermis. The submergence sensitivity of T. auriculata was associated with swelling and rupturing of the succulent stem tissues, which did not occur in T. medusa. The higher submergence tolerance of T. medusa was not associated with better internal aeration of stems. Rather, this species has poor internal aeration of the succulent stems due to its less permeable epidermis; the low epidermal permeability might be related to resistance to swelling of succulent stem tissues when submerged. © The Author 2014. Published by

Sudden, probably coseismic submergence of Holocene trees and grass in coastal Washington State

DOE Office of Scientific and Technical Information (OSTI.GOV)

Atwater, B.F.; Yamaguchi, D.K.

Growth-position plant fossils in coastal Washington State imply a suddenness of Holocene submergence that is better explained coseismic lowering of the land than be decade- or century-long rise of the sea. These fossils include western red cedar and Sitka spruce whose death probably resulted from estuarine submergence close to 300 years ago. Rings in eroded, bark-free trunks of the red cedar show that growth remained normal within decades of death. Rings in buried, bark-bearing stumps of the spruce further show normal growth continuing until the year of death. Other growth-position fossils implying sudden submergence include the stems and leaves ofmore » salt-marsh grass entombed in tide-flat mud close to 300 years ago and roughly 1,700 and 3,100 years ago. The preservation of these stems and leaves shows that submergence and initial burial outpaced decomposition, which appears to take just a few years in modern salt marshes. In some places the stems and leaves close to 300 year old are surrounded by sand left by an extraordinary, landward-directed surge-probably a tsunami from a great thrust earthquake on the Cascadia subduction zone.« less

Analysis of a Channeled Centerbody Supersonic Inlet for F-15B Flight Research

NASA Technical Reports Server (NTRS)

Ratnayake, Nalin A.

2010-01-01

The Propulsion Flight Test Fixture at the NASA Dryden Flight Research Center is a unique test platform available for use on the NASA F-15B airplane, tail number 836, as a modular host for a variety of aerodynamics and propulsion research. The first experiment that is to be flown on the test fixture is the Channeled Centerbody Inlet Experiment. The objectives of this project at Dryden are twofold: 1) flight evaluation of an innovative new approach to variable geometry for high-speed inlets, and 2) flight validation of channeled inlet performance prediction by complex computational fluid dynamics codes. The inlet itself is a fixed-geometry version of a mixed-compression, variable-geometry, supersonic in- let developed by TechLand Research, Inc. (North Olmsted, Ohio) to improve the efficiency of supersonic flight at off-nominal conditions. The concept utilizes variable channels in the centerbody section to vary the mass flow of the inlet, enabling efficient operation at a range of flight conditions. This study is particularly concerned with the starting characteristics of the inlet. Computational fluid dynamics studies were shown to align well with analytical predictions, showing the inlet to remain unstarted as designed at the primary test point of Mach 1.5 at an equivalent pressure altitude of 29,500 ft local conditions. Mass-flow-related concerns such as the inlet start problem, as well as inlet efficiency in terms of total pressure loss, are assessed using the flight test geometry.

Inlet Geomorphology Evolution Work Unit

DTIC Science & Technology

2015-10-30

Research Facility in Duck , North Carolina in coming years. In collaboration with the CMS work unit, an analysis of long-term inlet morphology...the expected behavior and benefits of nearshore placement. Nearshore placement studies have been documented in two journal papers, one technical

Inlet Flow Valve Engine Analyses

NASA Technical Reports Server (NTRS)

Champagne, G. A.

2004-01-01

Pratt&Whitney, under Task Order 13 of the NASA Large Engine Technology (LET) Contract, conducted a study to determine the operating characteristics, performance and weights of Inlet Flow Valve (IFV) propulsion concepts for a Mach 2.4 High Speed Civil Transport (HSCT).

A One Dimensional, Time Dependent Inlet/Engine Numerical Simulation for Aircraft Propulsion Systems

NASA Technical Reports Server (NTRS)

Garrard, Doug; Davis, Milt, Jr.; Cole, Gary

1999-01-01

The NASA Lewis Research Center (LeRC) and the Arnold Engineering Development Center (AEDC) have developed a closely coupled computer simulation system that provides a one dimensional, high frequency inlet/engine numerical simulation for aircraft propulsion systems. The simulation system, operating under the LeRC-developed Application Portable Parallel Library (APPL), closely coupled a supersonic inlet with a gas turbine engine. The supersonic inlet was modeled using the Large Perturbation Inlet (LAPIN) computer code, and the gas turbine engine was modeled using the Aerodynamic Turbine Engine Code (ATEC). Both LAPIN and ATEC provide a one dimensional, compressible, time dependent flow solution by solving the one dimensional Euler equations for the conservation of mass, momentum, and energy. Source terms are used to model features such as bleed flows, turbomachinery component characteristics, and inlet subsonic spillage while unstarted. High frequency events, such as compressor surge and inlet unstart, can be simulated with a high degree of fidelity. The simulation system was exercised using a supersonic inlet with sixty percent of the supersonic area contraction occurring internally, and a GE J85-13 turbojet engine.

Impact of Hurricanes and Nor'easters on a Migrating Inlet System

NASA Astrophysics Data System (ADS)

Hopkins, J.; Elgar, S.; Raubenheimer, B.

2016-12-01

After breaching in 2007, Katama Inlet, connecting Katama Bay to the Atlantic Ocean on the south shore of Martha's Vineyard, MA, migrated 2 km until it closed in 2015. Bathymetric surveys before and after Hurricanes Irene (2011) and Sandy (2012) indicate the strong waves and currents associated with these storms caused 2 m of erosion and deposition around the inlet mouth. The waves, currents, and bathymetric change observed during the hurricanes were used to validate the hydrodynamic and morphodynamic components of a Delft3D numerical model of the Martha's Vineyard coastline for storm (> 3 m wave heights) conditions. When driven with observed bathymetry and offshore waves, as well as simulated (WaveWatch3) winds and barometric pressures, the model reproduces the pattern and range of bathymetric change observed around the inlet. Model simulations of realistic (i.e., Irene and Sandy) and idealized storm conditions with a range of durations and wave conditions are used to test the relative importance of short-duration, high-intensity storms (hurricanes) and longer-duration, lower-intensity storms (nor'easters) on inlet migration. The simulations suggest that longer-duration, lower-intensity storms cause a higher range and variance in bathymetric change around the inlet than shorter-duration, higher-intensity storms. However, the simulations also suggest that the storm-induced migration of the inlet depends more on the wave direction at the peak of the storm than on the duration of the storm peak. The effect of storms on inlet migration over yearly time scales will be discussed. Funded by NSF, NOAA, ONR, and ASD(R&E).

METHODS TO DEFINE MARSH EVALUATION AND PERCENT SUBMERGENCE

EPA Science Inventory

Elevation can determine the percentage submergence from tides and therefore is one of the controlling factors for plant zonation within salt marshes. To make comparisons among plants from various salt marshes throughout Narragansett Bay, Rhode Island, a method was developed to es...

NACA D-558-2 Test Force w/P2B-1S & F-86

NASA Technical Reports Server (NTRS)

1952-01-01

These people and this equipment supported the flight of the NACA D-558-2 Skyrocket at the High-Speed Flight Station at South Base, Edwards AFB. Note the two Sabre chase planes, the P2B-1S launch aircraft, and the profusion of ground support equipment, including communications, tracking, maintenance, and rescue vehicles. Research pilot A. Scott Crossfield stands in front of the Skyrocket. Three D-558-2 'Skyrockets' were built by Douglas Aircraft, Inc. for NACA and the Navy. The mission of the D-558-2 program was to investigate the flight characteristics of a swept-wing aircraft at high supersonic speeds. Particular attention was given to the problem of 'pitch-up,' a phenomenon often encountered with swept-wing configured aircraft. The D-558-2 was a single-place, 35-degree swept-wing aircraft measuring 42 feet in length. It was 12 feet, 8 inches in height and had a wingspan of 25 feet. Fully fueled it weighed from about 10,572 pounds to 15,787 pounds depending on configuration. The first of the three D-558-IIs had a Westinghouse J34-40 jet engine and took off under its own power. The second was equipped with a turbojet engine replaced in 1950 with a Reaction Motors Inc. LR8-RM-6 rocket engine. This aircraft was modified so it could be air-launched from a P2B-1S (Navy designation for the B-29) carrier aircraft. The third Skyrocket had the jet engine and the rocket engine but was also modified so it could be air-launched. The jet engine was for takeoff and climbing to altitude and the four-chambered rocket engine was for reaching supersonic speeds. The rocket engine was rated at 6,000 pounds of thrust. The D-558-2 was first flown on Feb. 4, 1948, by John Martin, a Douglas test pilot. A NACA pilot, Scott Crossfield, became the first person to fly faster than twice the speed of sound when he piloted the D-558-II to its maximum speed of 1,291 miles per hour on Nov. 20, 1953. Its peak altitude, 83,235 feet, a record in its day, was reached with USMC Lt. Col. Marion Carl

Parametric Inlet Tested in Glenn's 10- by 10-Foot Supersonic Wind Tunnel

NASA Technical Reports Server (NTRS)

Slater, John W.; Davis, David O.; Solano, Paul A.

2005-01-01

The Parametric Inlet is an innovative concept for the inlet of a gas-turbine propulsion system for supersonic aircraft. The concept approaches the performance of past inlet concepts, but with less mechanical complexity, lower weight, and greater aerodynamic stability and safety. Potential applications include supersonic cruise aircraft and missiles. The Parametric Inlet uses tailored surfaces to turn the incoming supersonic flow inward toward an axis of symmetry. The terminal shock spans the opening of the subsonic diffuser leading to the engine. The external cowl area is smaller, which reduces cowl drag. The use of only external supersonic compression avoids inlet unstart--an unsafe shock instability present in previous inlet designs that use internal supersonic compression. This eliminates the need for complex mechanical systems to control unstart, which reduces weight. The conceptual design was conceived by TechLand Research, Inc. (North Olmsted, OH), which received funding through NASA s Small-Business Innovation Research program. The Boeing Company (Seattle, WA) also participated in the conceptual design. The NASA Glenn Research Center became involved starting with the preliminary design of a model for testing in Glenn s 10- by 10-Foot Supersonic Wind Tunnel (10 10 SWT). The inlet was sized for a speed of Mach 2.35 while matching requirements of an existing cold pipe used in previous inlet tests. The parametric aspects of the model included interchangeable components for different cowl lip, throat slot, and sidewall leading-edge shapes and different vortex generator configurations. Glenn researchers used computational fluid dynamics (CFD) tools for three-dimensional, turbulent flow analysis to further refine the aerodynamic design.

Vibration analysis of partially cracked plate submerged in fluid

NASA Astrophysics Data System (ADS)

Soni, Shashank; Jain, N. K.; Joshi, P. V.

2018-01-01

The present work proposes an analytical model for vibration analysis of partially cracked rectangular plates coupled with fluid medium. The governing equation of motion for the isotropic plate based on the classical plate theory is modified to accommodate a part through continuous line crack according to simplified line spring model. The influence of surrounding fluid medium is incorporated in the governing equation in the form of inertia effects based on velocity potential function and Bernoulli's equations. Both partially and totally submerged plate configurations are considered. The governing equation also considers the in-plane stretching due to lateral deflection in the form of in-plane forces which introduces geometric non-linearity into the system. The fundamental frequencies are evaluated by expressing the lateral deflection in terms of modal functions. The assessment of the present results is carried out for intact submerged plate as to the best of the author's knowledge the literature lacks in analytical results for submerged cracked plates. New results for fundamental frequencies are presented as affected by crack length, fluid level, fluid density and immersed depth of plate. By employing the method of multiple scales, the frequency response and peak amplitude of the cracked structure is analyzed. The non-linear frequency response curves show the phenomenon of bending hardening or softening and the effect of fluid dynamic pressure on the response of the cracked plate.

Computational Analyses of the LIMX TBCC Inlet High-Speed Flowpath

NASA Technical Reports Server (NTRS)

Dippold, Vance F., III

2012-01-01

Reynolds-Averaged Navier-Stokes (RANS) simulations were performed for the high-speed flowpath and isolator of a dual-flowpath Turbine-Based Combined-Cycle (TBCC) inlet using the Wind-US code. The RANS simulations were performed in preparation for the Large-scale Inlet for Mode Transition (LIMX) model tests in the NASA Glenn Research Center (GRC) 10- by 10-ft Supersonic Wind Tunnel. The LIMX inlet has a low-speed flowpath that is coupled to a turbine engine and a high-speed flowpath designed to be coupled to a Dual-Mode Scramjet (DMSJ) combustor. These RANS simulations were conducted at a simulated freestream Mach number of 4.0, which is the nominal Mach number for the planned wind tunnel testing with the LIMX model. For the simulation results presented in this paper, the back pressure, cowl angles, and freestream Mach number were each varied to assess the performance and robustness of the high-speed inlet and isolator. Under simulated wind tunnel conditions at maximum inlet mass flow rates, the high-speed flowpath pressure rise was found to be greater than a factor of four. Furthermore, at a simulated freestream Mach number of 4.0, the high-speed flowpath and isolator showed stability for freestream Mach number that drops 0.1 Mach below the design point. The RANS simulations indicate the yet-untested highspeed inlet and isolator flowpath should operate as designed. The RANS simulation results also provided important insight to researchers as they developed test plans for the LIMX experiment in GRC s 10- by 10-ft Supersonic Wind Tunnel.

Elevation dynamics in a restored versus a submerging salt marsh in Long Island Sound

USGS Publications Warehouse

Anisfeld, Shimon C.; Hill, Troy D.; Cahoon, Donald R.

2016-01-01

Accelerated sea-level rise (SLR) poses the threat of salt marsh submergence, especially in marshes that are relatively low-lying. At the same time, restoration efforts are producing new low-lying marshes, many of which are thriving and avoiding submergence. To understand the causes of these different fates, we studied two Long Island Sound marshes: one that is experiencing submergence and mudflat expansion, and one that is undergoing successful restoration. We examined sedimentation using a variety of methods, each of which captures different time periods and different aspects of marsh elevation change: surface-elevation tables, marker horizons, sediment cores, and sediment traps. We also studied marsh hydrology, productivity, respiration, nutrient content, and suspended sediment. We found that, despite the expansion of mudflat in the submerging marsh, the areas that remain vegetated have been gaining elevation at roughly the rate of SLR over the last 10 years. However, this elevation gain was only possible thanks to an increase in belowground volume, which may be a temporary response to waterlogging. In addition, accretion rates in the first half of the twentieth century were much lower than current rates, so century-scale accretion in the submerging marsh was lower than SLR. In contrast, at the restored marsh, accretion rates are now averaging about 10 mm yr−1 (several times the rate of SLR), much higher than before restoration. The main cause of the different trajectories at the two marshes appeared to be the availability of suspended sediment, which was much higher in the restored marsh. We considered and rejected alternative hypotheses, including differences in tidal flooding, plant productivity, and nutrient loading. In the submerging marsh, suspended and deposited sediment had relatively high organic content, which may be a useful indicator of sediment starvation.

Jet Engine Fan Response to Inlet Distortions Generated by Ingesting Boundary Layer Flow

NASA Astrophysics Data System (ADS)

Giuliani, James Edward

Future civil transport designs may incorporate engines integrated into the body of the aircraft to take advantage of efficiency increases due to weight and drag reduction. Additional increases in engine efficiency are predicted if the inlets ingest the lower momentum boundary layer flow that develops along the surface of the aircraft. Previous studies have shown, however, that the efficiency benefits of Boundary Layer Ingesting (BLI) inlets are very sensitive to the magnitude of fan and duct losses, and blade structural response to the non-uniform flow field that results from a BLI inlet has not been studied in-depth. This project represents an effort to extend the modeling capabilities of TURBO, an existing rotating turbomachinery unsteady analysis code, to include the ability to solve the external and internal flow fields of a BLI inlet. The TURBO code has been a successful tool in evaluating fan response to flow distortions for traditional engine/inlet integrations. Extending TURBO to simulate the external and inlet flow field upstream of the fan will allow accurate pressure distortions that result from BLI inlet configurations to be computed and used to analyze fan aerodynamics and structural response. To validate the modifications for the BLI inlet flow field, an experimental NASA project to study flush-mounted S-duct inlets with large amounts of boundary layer ingestion was modeled. Results for the flow upstream and in the inlet are presented and compared to experimental data for several high Reynolds number flows to validate the modifications to the solver. Once the inlet modifications were validated, a hypothetical compressor fan was connected to the inlet, matching the inlet operating conditions so that the effect on the distortion could be evaluated. Although the total pressure distortion upstream of the fan was symmetrical for this geometry, the pressure rise generated by the fan blades was not, because of the velocity non-uniformity of the distortion

Na/Ca Intermixing around Silicate and Phosphate Groups in Bioactive Phosphosilicate Glasses Revealed by Heteronuclear Solid-State NMR and Molecular Dynamics Simulations.

PubMed

Mathew, Renny; Stevensson, Baltzar; Edén, Mattias

2015-04-30

We characterize the intermixing of network-modifying Na(+)/Ca(2+) ions around the silicate (QSi(n)) and phosphate (QP(n)) tetrahedra in a series of 16 Na2O–CaO–SiO2–P2O5 glasses, whose P content and silicate network connectivity were varied independently. The set includes both bioactive and bioinactive compositions and also encompasses two soda-lime-silicate members devoid of P, as well as two CaO–SiO2 glasses and one Na2O–SiO2–P2O5 glass. The various Si/P↔Na/Ca contacts were probed by molecular dynamics (MD) simulations together with heteronuclear magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) experimentation utilizing (23)Na{(31)P} and (23)Na{(29)Si} REDOR, as well as (31)P{ (23)Na} and (29)Si{(23)Na} REAPDOR. We introduce an approach for quantifying the extent of Na(+)/Ca(2+) ordering around a given QP(n) or QSi(n) group, encoded by the preference factor 0⩽ PM ⩽ 1 conveying the relative weights of a random cation intermixing (PM = 0) and complete preference/ordering (PM = 1) for one of the species M, which represents either Na(+) or Ca(2+). The MD-derived preference factors reveal phosphate and silicate species surrounded by Na(+)/Ca(2+) ions intermixed nearly randomly (PM ≲ 0.15), except for the QSi(4) and QSi(1) groups, which manifest more significant cation ordering with preference for Na+ and Ca2+, respectively. The overall weak preferences are essentially independent of the Si and P contents of the glass, whereas PM primarily correlates with the total amount of network modifiers: as the latter is increased, the Na/Ca distribution around the {QP(0), QSi(1), QSi(2)} groups with preference for Ca2(+ )tend to randomize (i.e., PCa decreases), while the PNa-values grow slightly for the {QP(1), QSi(3), QSi(4)} species already preferring coordination of Na. The set of experimental preference factors {PCa} for the orthophosphate (QP(0)) groups extracted from (31)P{(23)Na} REAPDOR NMR-derived M2(P–Na) dipolar second moments agrees

Implementing regional sediment management to sustain navigation at an energetic tidal inlet

USGS Publications Warehouse

Moritz, H.R.; Gelfenbaum, G.R.; Kaminsky, G.M.; Ruggiero, P.; Oltman-shay, J.; Mckillip, D.J.

2007-01-01

Regional Sediment Management (RSM) is a systems-based approach for managing multiple projects involving sediment. RSM fosters balance between infrastructure and natural system processes, resulting in reduced project costs and achievement of greater benefits. This paper introduces the RSM concept and describes how RSM is being implemented at the Mouth of the Columbia River to sustain the inlet's 100-year old navigation infrastructure and adjacent shore lands. Implementing RSM at this energetic inlet involves feeding the inlet's morphology using dredged material, and letting nature do the work of dispersing the placed dredged material to supplement the inlet's sediment budget, without compromising the reliability of the navigation channel. The paper discusses the types of data that are being collected and analyzed to understand the environmental forcing affecting the inlet's morphology. The paper also addresses how dredged material disposal is being conducted to implement RSM.

Velocity distributions on two-dimensional wing-duct inlets by conformal mapping

NASA Technical Reports Server (NTRS)

Perl, W; Moses, H E

1948-01-01

The conformal-mapping method of the Cartesian mapping function is applied to the determination of the velocity distribution on arbitrary two-dimensional duct-inlet shapes such as are used in wing installations. An idealized form of the actual wing-duct inlet is analyzed. The effects of leading edge stagger, inlet-velocity ratio, and section lift coefficients on the velocity distribution are included in the analysis. Numerical examples are given and, in part, compared with experimental data.

The Enlarged N.A.C.A. Tank, and Some of Its Work

NASA Technical Reports Server (NTRS)

Truscott, Starr

1939-01-01

The most conspicuous of the features of the enlarged N.A.C.A. tank are derived directly from those of the original tank and owe their present form not only to the reasons for their first use but also to the experience obtained with them. As in the original tank, there are: 1) A basin of great length (new 2,880 feet); 2) Rails made of structural H beams, without machining; 3) A towing carriage of very high speed (now 80 mph maximum); 4) Rubber tires on all the wheels, pneumatic on the running wheels and solid on the guide wheels.

Internal aeration of paddy field rice (Oryza sativa) during complete submergence---importance of light and floodwater O2.

PubMed

Winkel, Anders; Colmer, Timothy D; Ismail, Abdelbagi M; Pedersen, Ole

2013-03-01

Flash floods can submerge paddy field rice (Oryza sativa), with adverse effects on internal aeration, sugar status and survival. Here, we investigated the in situ aeration of roots of rice during complete submergence, and elucidated how underwater photosynthesis and floodwater pO(2) influence root aeration in anoxic soil. In the field, root pO(2) was measured using microelectrodes during 2 d of complete submergence. Leaf gas films that formed on the superhydrophobic leaves were left intact, or experimentally removed, to elucidate their effect on internal aeration. In darkness, root pO(2) declined to very low concentrations (0.24 kPa) and was strongly correlated with floodwater pO(2). In light, root pO(2) was high (14 kPa) and primarily a function of the incident light determining the rates of underwater net photosynthesis. Plants with intact leaf gas films maintained higher underwater net photosynthesis relative to plants without gas films when the submerged shoots were in light. During complete submergence, internal aeration of rice in the field relies on underwater photosynthesis during the day and entry of O(2) from the floodwater during the night. Leaf gas films enhance photosynthesis during submergence leading to improved O(2) production and sugar status, and therefore contribute to the submergence tolerance of rice. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Shock position sensor for supersonic inlets. [measuring pressure in the throat of a supersonic inlet

NASA Technical Reports Server (NTRS)

Dustin, M. O. (Inventor)

1975-01-01

Static pressure taps or ports are provided in the throat of a supersonic inlet, and signals indicative of the pressure at each of the ports is fed to respective comparators. Means are also provided for directing a signal indicative of the total throat pressure to the comparators. A periodic signal is superimposed on the total throat pressure so that the signal from the static pressure tabs is compared to a varying scan signal rather than to total throat pressure only. This type of comparison causes each comparator to provide a pulse width modulated output which may vary from 0% 'time on' to 100% 'time on'. The pulse width modulated outputs of the comparators are summed, filtered, and directed to a controller which operates a bypass valve such as a door whereby air is dumped from the inlet to prevent the shock wave from being expelled out the front.

Validation of WIND for a Series of Inlet Flows

NASA Technical Reports Server (NTRS)

Slater, John W.; Abbott, John M.; Cavicchi, Richard H.

2002-01-01

Validation assessments compare WIND CFD simulations to experimental data for a series of inlet flows ranging in Mach number from low subsonic to hypersonic. The validation procedures follow the guidelines of the AIAA. The WIND code performs well in matching the available experimental data. The assessments demonstrate the use of WIND and provide confidence in its use for the analysis of aircraft inlets.

OCEAN OUTFALLS. II: SPATIAL EVOLUTION OF SUBMERGED WASTEFIELD

EPA Science Inventory

Some of the basic features of submerged wastefield formation in stratified currents are reported in this paper. ilution increased with distance from the diffuser in the initial mixing region until it attained a maximum value, which is the initial dilution, after which it remained...

Benthic bacterial diversity in submerged sinkhole ecosystems.

PubMed

Nold, Stephen C; Pangborn, Joseph B; Zajack, Heidi A; Kendall, Scott T; Rediske, Richard R; Biddanda, Bopaiah A

2010-01-01

Physicochemical characterization, automated ribosomal intergenic spacer analysis (ARISA) community profiling, and 16S rRNA gene sequencing approaches were used to study bacterial communities inhabiting submerged Lake Huron sinkholes inundated with hypoxic, sulfate-rich groundwater. Photosynthetic cyanobacterial mats on the sediment surface were dominated by Phormidium autumnale, while deeper, organically rich sediments contained diverse and active bacterial communities.

Micro-Ramps for External Compression Low-Boom Inlets

NASA Technical Reports Server (NTRS)

Rybalko, Michael; Loth, Eric; Chima, Rodrick V.; Hirt, Stefanie M.; DeBonis, James R.

2010-01-01

The application of vortex generators for flow control in an external compression, axisymmetric, low-boom concept inlet was investigated using RANS simulations with three-dimensional (3-D), structured, chimera (overset) grids and the WIND-US code. The low-boom inlet design is based on previous scale model 1- by 1-ft wind tunnel tests and features a zero-angle cowl and relaxed isentropic compression centerbody spike, resulting in defocused oblique shocks and a weak terminating normal shock. Validation of the methodology was first performed for micro-ramps in supersonic flow on a flat plate with and without oblique shocks. For the inlet configuration, simulations with several types of vortex generators were conducted for positions both upstream and downstream of the terminating normal shock. The performance parameters included incompressible axisymmetric shape factor, separation area, inlet pressure recovery, and massflow ratio. The design of experiments (DOE) methodology was used to select device size and location, analyze the resulting data, and determine the optimal choice of device geometry. The optimum upstream configuration was found to substantially reduce the post-shock separation area but did not significantly impact recovery at the aerodynamic interface plane (AIP). Downstream device placement allowed for fuller boundary layer velocity profiles and reduced distortion. This resulted in an improved pressure recovery and massflow ratio at the AIP compared to the baseline solid-wall configuration.

33 CFR 334.1210 - Admiralty Inlet, entrance; naval restricted area.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Admiralty Inlet, entrance; naval..., entrance; naval restricted area. (a) Admiralty Inlet, entrance; naval restricted area—(1) The area... prohibited. (ii) The regulations in this paragraph shall be enforced by the Commander, Naval Base, Seattle...

33 CFR 334.1210 - Admiralty Inlet, entrance; naval restricted area.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Admiralty Inlet, entrance; naval..., entrance; naval restricted area. (a) Admiralty Inlet, entrance; naval restricted area—(1) The area... prohibited. (ii) The regulations in this paragraph shall be enforced by the Commander, Naval Base, Seattle...

Inlets, ducts, and nozzles

NASA Technical Reports Server (NTRS)

Abbott, John M.; Anderson, Bernhard H.; Rice, Edward J.

1990-01-01

The internal fluid mechanics research program in inlets, ducts, and nozzles consists of a balanced effort between the development of computational tools (both parabolized Navier-Stokes and full Navier-Stokes) and the conduct of experimental research. The experiments are designed to better understand the fluid flow physics, to develop new or improved flow models, and to provide benchmark quality data sets for validation of the computational methods. The inlet, duct, and nozzle research program is described according to three major classifications of flow phenomena: (1) highly 3-D flow fields; (2) shock-boundary-layer interactions; and (3) shear layer control. Specific examples of current and future elements of the research program are described for each of these phenomenon. In particular, the highly 3-D flow field phenomenon is highlighted by describing the computational and experimental research program in transition ducts having a round-to-rectangular area variation. In the case of shock-boundary-layer interactions, the specific details of research for normal shock-boundary-layer interactions are described. For shear layer control, research in vortex generators and the use of aerodynamic excitation for enhancement of the jet mixing process are described.

Aerothermo-Structural Analysis of Low Cost Composite Nozzle/Inlet Components

NASA Technical Reports Server (NTRS)

Shivakumar, Kuwigai; Challa, Preeli; Sree, Dave; Reddy, D.

1999-01-01

This research is a cooperative effort among the Turbomachinery and Propulsion Division of NASA Glenn, CCMR of NC A&T State University, and the Tuskegee University. The NC A&T is the lead center and Tuskegee University is the participating institution. Objectives of the research were to develop an integrated aerodynamic, thermal and structural analysis code for design of aircraft engine components, such as, nozzles and inlets made of textile composites; conduct design studies on typical inlets for hypersonic transportation vehicles and setup standards test examples and finally manufacture a scaled down composite inlet. These objectives are accomplished through the following seven tasks: (1) identify the relevant public domain codes for all three types of analysis; (2) evaluate the codes for the accuracy of results and computational efficiency; (3) develop aero-thermal and thermal structural mapping algorithms; (4) integrate all the codes into one single code; (5) write a graphical user interface to improve the user friendliness of the code; (6) conduct test studies for rocket based combined-cycle engine inlet; and finally (7) fabricate a demonstration inlet model using textile preform composites. Tasks one, two and six are being pursued. Selected and evaluated NPARC for flow field analysis, CSTEM for in-depth thermal analysis of inlets and nozzles and FRAC3D for stress analysis. These codes have been independently verified for accuracy and performance. In addition, graphical user interface based on micromechanics analysis for laminated as well as textile composites was developed. Demonstration of this code will be made at the conference. A rocket based combined cycle engine was selected for test studies. Flow field analysis of various inlet geometries were studied. Integration of codes is being continued. The codes developed are being applied to a candidate example of trailblazer engine proposed for space transportation. A successful development of the code will

Seasonal shorebird use of intertidal habitats in Cook Inlet, Alaska

USGS Publications Warehouse

Gill, Robert E.; Tibbitts, T. Lee

1999-01-01

Seasonal shorebird use of intertidal habitats of Cook Inlet, Alaska, was studied from February 1997 to February 1999 using aerial surveys as the principal method of assessment. On-ground studies were conducted to validate aerial survey results and to assess shorebird use of vegetated habitats, especially during the breeding season. Twenty-eight species of shorebirds were recorded using the area, ranging from all being present during spring to a single species present during winter. The annual pattern of use was characterized by the sudden occurrence and rapid increase in numbers of birds during early May and their abrupt departure in mid- to late-May. During this period, survey totals frequently exceeded 150,000 birds per day. Comparatively little use occurred during summer and autumn, but use was significant from late autumn to early spring when Rock Sandpipers (Calidris ptilocnemis) resided in the Inlet. A single species, the Western Sandpiper (C. maun), was by far the numerically dominant shorebird, accounting for three-fourths of all birds recorded. The Pacific flyway population of this species numbers 2-3 million birds of which we estimated 20-47% used Cook Inlet embayments, especially southern Redoubt Bay. Cook .Inlet also supported between 11 and 21% of the Pacific flyway population of Dunlin (C. alpina pacifica) and what may be the entire population (ca. 20,000 birds) of the nominate race of the Rock Sandpiper (C. p. ptilocnemis). Several areas along the west side of Cook Inlet proved to be extremely important to shorebirds. Southern Redoubt Bay supported 73% of all shorebirds during spring (average 32,000 per day) while Susitna Flats accounted for 82% of use during winter (8,400 per day). International criteria used to assess the conservation importance of particular wetland sites to shorebirds not only place Cook Inlet at the highest level of recognition but afford similar recognition to several individual embayments therein. The large human population

Preliminary Investigation of a New Type of Supersonic Inlet

NASA Technical Reports Server (NTRS)

Ferri, Antonio; Nucci, Louis M

1946-01-01

A supersonic inlet with supersonic deceleration of the flow entirely outside of the inlet is considered. A particular arrangement with fixed geometry having a central body with a circular annular intake is analyzed, and it is shown theoretically that this arrangement gives high pressure recovery for a large range of Mach number and mass flow and therefore is practical for use on supersonic airplanes and missiles. For some Mach numbers the drag coefficient for this type of inlet is larger than the drag coefficient for the type of inlet with supersonic compression entirely inside, but the pressure recovery is larger for all flight conditions. The differences in drag can be eliminated for the design Mach number. Experimental results confirm the results of the theoretical analysis and show that pressure recoveries of 95 percent for Mach numbers of 1.33 and 1.52, 92 percent for a Mach number of 1.72, and 86 percent for a Mach number oof 2.10 are possible with the configurations considered. If the mass flow decreases, the total drag coefficient increases gradually and the pressure recovery does not change appreciably.

Classifier utility modeling and analysis of hypersonic inlet start/unstart considering training data costs

NASA Astrophysics Data System (ADS)

Chang, Juntao; Hu, Qinghua; Yu, Daren; Bao, Wen

2011-11-01

Start/unstart detection is one of the most important issues of hypersonic inlets and is also the foundation of protection control of scramjet. The inlet start/unstart detection can be attributed to a standard pattern classification problem, and the training sample costs have to be considered for the classifier modeling as the CFD numerical simulations and wind tunnel experiments of hypersonic inlets both cost time and money. To solve this problem, the CFD simulation of inlet is studied at first step, and the simulation results could provide the training data for pattern classification of hypersonic inlet start/unstart. Then the classifier modeling technology and maximum classifier utility theories are introduced to analyze the effect of training data cost on classifier utility. In conclusion, it is useful to introduce support vector machine algorithms to acquire the classifier model of hypersonic inlet start/unstart, and the minimum total cost of hypersonic inlet start/unstart classifier can be obtained by the maximum classifier utility theories.

Calculation of compressible flow about three-dimensional inlets with auxiliary inlets, slats and vanes by means of a panel method

NASA Technical Reports Server (NTRS)

Hess, J. L.; Friedman, D. M.; Clark, R. W.

1985-01-01

An efficient and user oriented method was constructed for calculating flow in and about complex inlet configurations. Efficiency is attained by: (1) the use of a panel method; (2) a technique of superposition for obtaining solutions at any inlet operating condition; and (3) employment of an advanced matrix iteration technique for solving large full systems of equations, including the nonlinear equations for the Kutta condition. User concerns are addressed by the provision of several novel graphical output options that yield a more complete comprehension of the flowfield than was possible previously.

Design of Three-Dimensional Hypersonic Inlets with Rectangular to Elliptical Shape Transition

NASA Technical Reports Server (NTRS)

Smart, M. K.

1998-01-01

A methodology has been devised for the design of three-dimensional hypersonic inlets which include a rectangular to elliptical shape transition. This methodology makes extensive use of inviscid streamtracing techniques to generate a smooth shape transition from a rectangular-like capture to an elliptical throat. Highly swept leading edges and a significantly notched cowl enable use of these inlets in fixed geometry configurations. The design procedure includes a three dimensional displacement thickness calculation and uses established correlations to check for boundary layer separation due to shock wave interactions. Complete details of the design procedure are presented and the characteristics of a modular inlet with rectangular to elliptical shape transition and a design point of Mach 7.1 are examined. Comparison with a classical two-dimensional inlet optimized for maximum total pressure recovery indicates that this three-dimensional inlet demonstrates good performance even well below its design point.

A life-cycle model for wave-dominated tidal inlets along passive margin coasts of North America

NASA Astrophysics Data System (ADS)

Seminack, Christopher T.; McBride, Randolph A.

2018-03-01

A regional overview of 107 wave-dominated tidal inlets along the U.S. Atlantic coast, U.S. Gulf of Mexico coast, and Canadian Gulf of St. Lawrence coast yielded a generalized wave-dominated tidal inlet life-cycle model that recognized the rotational nature of tidal inlets. Tidal inlets are influenced by concurrently acting processes transpiring over two timescales: short-term, event-driven processes and long-term, evolutionary processes. Wave-dominated tidal inlets are classified into three rotational categories based on net longshore sediment transport direction and rotation direction along the landward (back-barrier) portion of the inlet channel: downdrift channel rotation, updrift channel rotation, or little-to-no channel rotation. Lateral shifting of the flood-tidal delta depocenter in response to available estuarine accommodation space appears to control inlet channel rotation. Flood-tidal delta deposits fill accommodation space locally within the estuary (i.e., creating bathymetric highs), causing the tidal-inlet channel to rotate. External influences, such as fluvial discharge, pre-existing back-barrier channels, and impeding salt marsh will also influence inlet-channel rotation. Storm events may rejuvenate the tidal inlet by scouring sediment within the flood-tidal delta, increasing local accommodation space. Wave-dominated tidal inlets are generally unstable and tend to open, concurrently migrate laterally and rotate, infill, and close. Channel rotation is a primary reason for wave-dominated tidal inlet closure. During rotation, the inlet channel lengthens and hydraulic efficiency decreases, thus causing tidal prism to decrease. Tidal prism, estuarine accommodation space, and sediment supply to the flood-tidal delta are the primary variables responsible for tidal inlet rotation. Stability of wave-dominated tidal inlets is further explained by: stability (S) = tidal prism (Ω) + estuarine accommodation space (V) - volume of annual sediment supply (Mt

Analysis of Porous Media as Inlet Concept for Rotating Detonation Engines

NASA Astrophysics Data System (ADS)

Grogan, Kevin; Ihme, Matthias; Department of Mechanical Engineering Team

2016-11-01

Rotating detonation engines combust reactive gas mixtures with a high-speed, annularly-propagating detonation wave, which provides many advantages including a stagnation pressure gain and a compact, lightweight design. However, the optimal design of the inlet to the combustion chamber inlet is a moot topic since improper design can significantly reduce detonability and increase pressure losses. The highly diffusive properties of porous media could make it an ideal material to prevent the flashback of the detonation wave and therefore, allow the inlet gas to be premixed. Motivated by this potential, this work employs simulation to evaluate the application of porous media to the inlet of a rotating detonation engine as a novel means to stabilize a detonation wave while reducing the pressure losses incurred by non-ideal mixing strategies. Department of the Air Force.

Nuclear reactor fuel assembly duct-tube-to-inlet-nozzle attachment system

DOEpatents

Christiansen, David W.; Smith, Bob G.

1982-01-01

A reusable system for removably attaching the lower end 21 of a nuclear reactor fuel assembly duct tube to an upper end 11 of a nuclear reactor fuel assembly inlet nozzle. The duct tube's lower end 21 has sides terminating in locking tabs 22 which end in inwardly-extending flanges 23. The flanges 23 engage recesses 13 in the top section 12 of the inlet nozzle's upper end 11. A retaining collar 30 slides over the inlet nozzle's upper end 11 to restrain the flanges 23 in the recesses 13. A locking nut 40 has an inside threaded portion 41 which engages an outside threaded portion 15 of the inlet nozzle's upper end 11 to secure the retaining collar 30 against protrusions 24 on the duct tube's sides.

Effect of vortex inlet mode on low-power cylindrical Hall thruster

NASA Astrophysics Data System (ADS)

Ding, Yongjie; Jia, Boyang; Xu, Yu; Wei, Liqiu; Su, Hongbo; Li, Peng; Sun, Hezhi; Peng, Wuji; Cao, Yong; Yu, Daren

2017-08-01

This paper examines a new propellant inlet mode for a low-power cylindrical Hall thruster called the vortex inlet mode. This new mode makes propellant gas diffuse in the form of a circumferential vortex in the discharge channel of the thruster. Simulation and experimental results show that the neutral gas density in the discharge channel increases upon the application of the vortex inlet mode, effectively extending the dwell time of the propellant gas in the channel. According to the experimental results, the vortex inlet increases the propellant utilization of the thruster by 3.12%-8.81%, thrust by 1.1%-53.5%, specific impulse by 1.1%-53.5%, thrust-to-power ratio by 10%-63%, and anode efficiency by 1.6%-7.3%, greatly improving the thruster performance.

A preliminary investigation of inlet unstart effects on a high-speed civil transport concept

NASA Technical Reports Server (NTRS)

Domack, Christopher S.

1991-01-01

Vehicle motions resulting from a supersonic mixed-compression inlet unstart were examined to determine if the unstart constituted a hazard severe enough to warrant rejection of mixed-compression inlets on high-speed civil transport (HSCT) concepts. A simple kinematic analysis of an inlet unstart during cruise was performed for a Mach 2, 4, 250-passenger HSCT concept using data from a wind-tunnel test of a representative configuration with unstarted inlets simulated. A survey of previously published research on inlet unstart effects, including simulation and flight test data for the YF-12, XB-70, and Concorde aircraft, was conducted to validate the calculated results. It was concluded that, when countered by suitable automatic propulsion and flight control systems, the vehicle dynamics induced by an inlet unstart are not severe enough to preclude the use of mixed-compression inlets on an HSCT from a passenger safety standpoint. The ability to provide suitable automatic controls appears to be within the current state of the art. However, the passenger startle and discomfort caused by the noise, vibration, and cabin motions associated with an inlet unstart remain a concern.

Development of a prototype automatic controller for liquid cooling garment inlet temperature

NASA Technical Reports Server (NTRS)

Weaver, C. S.; Webbon, B. W.; Montgomery, L. D.

1982-01-01

The development of a computer control of a liquid cooled garment (LCG) inlet temperature is descirbed. An adaptive model of the LCG is used to predict the heat-removal rates for various inlet temperatures. An experimental system that contains a microcomputer was constructed. The LCG inlet and outlet temperatures and the heat exchanger outlet temperature form the inputs to the computer. The adaptive model prediction method of control is successful during tests where the inlet temperature is automatically chosen by the computer. It is concluded that the program can be implemented in a microprocessor of a size that is practical for a life support back-pack.

Examination of two lowland rice cultivars reveals that gibberellin-dependent early response to submergence is not necessarily mediated by ethylene.

PubMed

Dubois, Vincent; Moritz, Thomas; García-Martínez, José L

2011-01-01

Using two lowland rice (Oryza sativa L.) cultivars we found that in both cases submerged-induced elongation early after germination depends on gibberellins (GAs). Submergence increases the content of the active GA 1 by enhancing the expression of GA biosynthesis genes, thus facilitating the seedlings to escape from the water and preventing asphyxiation. However, the two cultivars differ in their response to ethylene. The cultivar Senia (short), by contrast to cultivar Bomba (tall), does not elongate after ethylene application, and submerged-induced elongation is not negated by an inhibitor of ethylene perception. Also, while ethylene emanation in Senia is not altered by submergence, Bomba seedlings emanate more ethylene upon de-submergence, associated with enhanced expression of the ethylene biosynthesis gene OsACS5. The cultivar Senia thus allows the possibility of clarifying the role of ethylene and other factors as triggers of GA biosynthesis enhancement in rice seedlings under submergence.

Impact of inlet coherent motions on compressor performance

NASA Astrophysics Data System (ADS)

Forlese, Jacopo; Spoleti, Giovanni

2017-08-01

Automotive engine induction systems may be characterized by significant flow angularity and total pressure distortion at the compressor inlet. The impact of the swirl on compressor performance should be quantified to guide the design of the induction systems. In diesel engines, the presence of a valve for flow reduction and control of low pressure EGR recirculation could generate coherent motion and influence the performance of the compressor. Starting from experimental map, the compressor speed-lines have been simulated using a 3D CFD commercial code imposing different concept motion at the inlet. The swirl intensity, the direction and the number of vortices have been imposed in order to taking into account some combinations. Finally, a merit function has been defined to evaluate the performance of the compressor with the defined swirl concepts. The aim of the current work is to obtain an indication on the effect of a swirling motion at the compressor inlet on the engine performance and provide a guideline to the induction system design.

Integral Engine Inlet Particle Separator. Volume 1. Technology Program

DTIC Science & Technology

1975-07-01

inlet particle separators for future Army aircraft gas turbine engines . Appropriate technical personnel of this Directorate have reviewed this report...USAAMRDL-TR-75-31A I - / INTEGRAL ENGINE INLET PARTICLE SEPARATOR Volume I-- Technology Program General Electric Company Aircraft Engine Group...N1 i 9ap mm tm~qu INTRODUCTION The adverse environments in which Army equipment operates impose severe )enalties upon gas turbine engine performance

Integral Engine Inlet Particle Separator. Volume 2. Design Guide

DTIC Science & Technology

1975-08-01

herein will be used in the design of integral inlet particle separators for future Army aircraft gas turbine engines . Apprupriate technical personnel...OF INTEGRAL GAS TURBINE ENGINE SOLID PARTICLE INLET SEPARATORS, PHASE I, FEASIBILITY STUDY AND DESIGN, Pratt and Whitney Aircraft ; USAAVLABS Technical...USAAVLABS Technical Report 70-36, U.S. Army Aviation Materiel Laboratories, Fort Eustis, Virginia, August 1970 AD 876 584. 13. ENGINES , AIRCRAFT

Hydrodynamic and Aerodynamic Tests of Four Models of Outboard Floats : (N.A.C.A. Models 51-A, 51-B, 51-C, and 51-D)

NASA Technical Reports Server (NTRS)

Dawson, John R; Hartman, Edwin P

1938-01-01

Four models of outboard floats (N.A.C.A. models 51-A, 51-B, 51-C, and 51-D) were tested in the N.A.C.A. tank to determine their hydrodynamic characteristics and in the 20-foot wind tunnel to determine their aerodynamic drag. The results of the tests, together with comparisons of them, are presented in the form of charts. From the comparisons, the order of merit of the models is estimated for each factor considered. The best compromise between the various factors seems to be given by model 51-D. This model is the only one in the series with a transverse step.

Investigation of a submerged membrane reactor for continuous biomass hydrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malmali, Mohammadmahdi; Stickel, Jonathan; Wickramasinghe, S. Ranil

Enzymatic hydrolysis of cellulose is one of the most costly steps in the bioconversion of lignocellulosic biomass. Use of a submerged membrane reactor has been investigated for continuous enzymatic hydrolysis of cellulose thus allowing for greater use of the enzyme compared to a batch process. Moreover, the submerged 0.65 μm polyethersulfone microfiltration membrane avoids the need to pump a cellulose slurry through an external loop. Permeate containing glucose is withdrawn at pressures slightly below atmospheric pressure. The membrane rejects cellulose particles and cellulase enzyme bound to cellulose. Our proof-of-concept experiments have been conducted using a modified, commercially available membrane filtrationmore » cell under low fluxes around 75 L/(m2 h). The operating flux is determined by the rate of glucose production. Maximizing the rate of glucose production involves optimizing mixing, reactor holding time, and the time the feed is held in the reactor prior to commencement of membrane filtration and continuous operation. When we maximize glucose production rates it will require that we operate it at low glucose concentration in order to minimize the adverse effects of product inhibition. Consequently practical submerged membrane systems will require a combined sugar concentration step in order to concentrate the product sugar stream prior to fermentation.« less

Euler Calculations at Off-Design Conditions for an Inlet of Inward Turning RBCC-SSTO Vehicle

NASA Technical Reports Server (NTRS)

Takashima, N.; Kothari, A. P.

1998-01-01

The inviscid performance of an inward turning inlet design is calculated computationally for the first time. Hypersonic vehicle designs based on the inward turning inlets have been shown analytically to have increased effective specific impulse and lower heat load than comparably designed vehicles with two-dimensional inlets. The inward turning inlets are designed inversely from inviscid stream surfaces of known flow fields. The computational study is performed on a Mach 12 inlet design to validate the performance predicted by the design code (HAVDAC) and calculate its off-design Mach number performance. The three-dimensional Euler equations are solved for Mach 4, 8, and 12 using a software package called SAM, which consists of an unstructured mesh generator (SAMmesh), a three-dimensional unstructured mesh flow solver (SAMcfd), and a CAD-based software (SAMcad). The computed momentum averaged inlet throat pressure is within 6% of the design inlet throat pressure. The mass-flux at the inlet throat is also within 7 % of the value predicted by the design code thereby validating the accuracy of the design code. The off-design Mach number results show that flow spillage is minimal, and the variation in the mass capture ratio with Mach number is comparable to an ideal 2-D inlet. The results from the inviscid flow calculations of a Mach 12 inward turning inlet indicate that the inlet design has very good on and off-design performance which makes it a promising design candidate for future air-breathing hypersonic vehicles.

Cooling Air Inlet and Exit Geometries on Aircraft Engine Installations

NASA Technical Reports Server (NTRS)

Katz, Joseph; Corsiglia, Victor R.; Barlow, Philip R.

1982-01-01

A semispan wing and nacelle of a typical general aviation twin-engine aircraft was tested to evaluate the cooling capability and drag or several nacelle shapes; the nacelle shapes included cooling air inlet and exit variations. The tests were conducted in the Ames Research Center 40 x 80-ft Wind Tunnel. It was found that the cooling air inlet geometry of opposed piston engine installations has a major effect on inlet pressure recovery, but only a minor effect on drag. Exit location showed large effect on drag, especially for those locations on the sides of the nacelle where the suction characteristics were based on interaction with the wing surface pressures.

General Investigation of Tidal Inlets: Stability of Selected United States Tidal Inlets

DTIC Science & Technology

1991-09-01

characteristics in relation to the variability of the hydr; aulic parameters. An inlet can fall into any of four "stability" classes 48 Orientation Parameter 80...nlot he ~ :Ke(: t 93. If a fairly straight coast with uniform offshore slopes and a regionally homogeneous wave climate is considered, a reasonable...expectation is LhaL the longshore transport quantities and directions are homogeneous. Given a long-term variability in wave climate , a corresponding

30 CFR 77.303 - Hot gas inlet chamber dropout doors.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Section 77.303 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND... employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet chamber...

Responses of bacterial community structure and denitrifying bacteria in biofilm to submerged macrophytes and nitrate

NASA Astrophysics Data System (ADS)

Zhang, Songhe; Pang, Si; Wang, Peifang; Wang, Chao; Guo, Chuan; Addo, Felix Gyawu; Li, Yi

2016-10-01

Submerged macrophytes play important roles in constructed wetlands and natural water bodies, as these organisms remove nutrients and provide large surfaces for biofilms, which are beneficial for nitrogen removal, particularly from submerged macrophyte-dominated water columns. However, information on the responses of biofilms to submerged macrophytes and nitrogen molecules is limited. In the present study, bacterial community structure and denitrifiers were investigated in biofilms on the leaves of four submerged macrophytes and artificial plants exposed to two nitrate concentrations. The biofilm cells were evenly distributed on artificial plants but appeared in microcolonies on the surfaces of submerged macrophytes. Proteobacteria was the most abundant phylum in all samples, accounting for 27.3-64.8% of the high-quality bacterial reads, followed by Chloroflexi (3.7-25.4%), Firmicutes (3.0-20.1%), Acidobacteria (2.7-15.7%), Actinobacteria (2.2-8.7%), Bacteroidetes (0.5-9.7%), and Verrucomicrobia (2.4-5.2%). Cluster analysis showed that bacterial community structure can be significantly different on macrophytes versus from those on artificial plants. Redundancy analysis showed that electrical conductivity and nitrate concentration were positively correlated with Shannon index and operational taxonomic unit (OTU) richness (log10 transformed) but somewhat negatively correlated with microbial density. The relative abundances of five denitrifying genes were positively correlated with nitrate concentration and electrical conductivity but negatively correlated with dissolved oxygen.

Vortex generator design for aircraft inlet distortion as a numerical optimization problem

NASA Technical Reports Server (NTRS)

Anderson, Bernhard H.; Levy, Ralph

1991-01-01

Aerodynamic compatibility of aircraft/inlet/engine systems is a difficult design problem for aircraft that must operate in many different flight regimes. Takeoff, subsonic cruise, supersonic cruise, transonic maneuvering, and high altitude loiter each place different constraints on inlet design. Vortex generators, small wing like sections mounted on the inside surfaces of the inlet duct, are used to control flow separation and engine face distortion. The design of vortex generator installations in an inlet is defined as a problem addressable by numerical optimization techniques. A performance parameter is suggested to account for both inlet distortion and total pressure loss at a series of design flight conditions. The resulting optimization problem is difficult since some of the design parameters take on integer values. If numerical procedures could be used to reduce multimillion dollar development test programs to a small set of verification tests, numerical optimization could have a significant impact on both cost and elapsed time to design new aircraft.

SUBMERGE! bringing the ocean closer to New York City

NASA Astrophysics Data System (ADS)

Rosengard, S.; Alexander, H.; Cramer, C.

2016-02-01

The annual SUBMERGE!-NYC marine science festival started in October 2014 as an effort to bring the ocean closer to the millions who live and work in the great estuary that is New York City. Organized by the Hudson River Park and the New York Hall of Science, the event brings together oceanography groups, musicians, and food vendors with distinct connections to the coastal ocean and the Hudson River estuary. Oceanography groups can either participate in the festival by giving a science talk during a specific time slot, or presenting science stations to teach concepts through a more interactive, exhibition-type format. Here, we discuss the experiences of graduate students from Woods Hole Oceanographic Institution who created a biological pump-themed science station for the first and second SUBMERGE! festivals (2014 and 2015). We will explore strategies for communicating different processes of the biological pump and its global significance for the oceans and climate. This festival-style setting also presents unique challenges in transferring knowledge, including how to evaluate successful transfer of knowledge. The festival is free and open to the public; the first year drew an audience of 4500, half of which were adults over 30 years old and a third of which were children under 11 years old. Therefore, SUBMERGE! provides an opportunity for graduate students to contribute to the ocean literacy of thousands of New Yorkers as well as a unique experience for graduate students to develop their skills in talking to the public.

Vortex Generators in a Two-Dimensional, External-Compression Supersonic Inlet

NASA Technical Reports Server (NTRS)

Baydar, Ezgihan; Lu, Frank K.; Slater, John W.

2016-01-01

Computational fluid dynamics simulations are performed as part of a process to design a vortex generator array for a two-dimensional inlet for Mach 1.6. The objective is to improve total pressure recovery a on at the engine face of the inlet. Both vane-type and ramp-type vortex generators are examined.

Parametric Data from a Wind Tunnel Test on a Rocket-Based Combined-Cycle Engine Inlet

NASA Technical Reports Server (NTRS)

Fernandez, Rene; Trefny, Charles J.; Thomas, Scott R.; Bulman, Mel J.

2001-01-01

A 40-percent scale model of the inlet to a rocket-based combined-cycle (RBCC) engine was tested in the NASA Glenn Research Center 1- by 1-Foot Supersonic Wind Tunnel (SWT). The full-scale RBCC engine is scheduled for test in the Hypersonic Tunnel Facility (HTF) at NASA Glenn's Plum Brook Station at Mach 5 and 6. This engine will incorporate the configuration of this inlet model which achieved the best performance during the present experiment. The inlet test was conducted at Mach numbers of 4.0, 5.0, 5.5, and 6.0. The fixed-geometry inlet consists of an 8 deg.. forebody compression plate, boundary layer diverter, and two compressive struts located within 2 parallel sidewalls. These struts extend through the inlet, dividing the flowpath into three channels. Test parameters investigated included strut geometry, boundary layer ingestion, and Reynolds number (Re). Inlet axial pressure distributions and cross-sectional Pitot-pressure surveys at the base of the struts were measured at varying back-pressures. Inlet performance and starting data are presented. The inlet chosen for the RBCC engine self-started at all Mach numbers from 4 to 6. Pitot-pressure contours showed large flow nonuniformity on the body-side of the inlet. The inlet provided adequate pressure recovery and flow quality for the RBCC cycle even with the flow separation.

Assessment of inlet efficiency through a 3D simulation: numerical and experimental comparison.

PubMed

Gómez, Manuel; Recasens, Joan; Russo, Beniamino; Martínez-Gomariz, Eduardo

2016-10-01

Inlet efficiency is a requirement for characterizing the flow transfers between surface and sewer flow during rain events. The dual drainage approach is based on the joint analysis of both upper and lower drainage levels, and the flow transfer is one of the relevant elements to define properly this joint behaviour. This paper presents the results of an experimental and numerical investigation about the inlet efficiency definition. A full scale (1:1) test platform located in the Technical University of Catalonia (UPC) reproduces both the runoff process in streets and the water entering the inlet. Data from tests performed on this platform allow the inlet efficiency to be estimated as a function of significant hydraulic and geometrical parameters. A reproduction of these tests through a numerical three-dimensional code (Flow-3D) has been carried out simulating this type of flow by solving the RANS equations. The aim of the work was to reproduce the hydraulic performance of a previously tested grated inlet under several flow and geometric conditions using Flow-3D as a virtual laboratory. This will allow inlet efficiencies to be obtained without previous experimental tests. Moreover, the 3D model allows a better understanding of the hydraulics of the flow interception and the flow patterns approaching the inlet.

Restoring Ecological Function to a Submerged Salt Marsh

USGS Publications Warehouse

Stagg, C.L.; Mendelssohn, I.A.

2010-01-01

Impacts of global climate change, such as sea level rise and severe drought, have altered the hydrology of coastal salt marshes resulting in submergence and subsequent degradation of ecosystem function. A potential method of rehabilitating these systems is the addition of sediment-slurries to increase marsh surface elevation, thus ameliorating effects of excessive inundation. Although this technique is growing in popularity, the restoration of ecological function after sediment addition has received little attention. To determine if sediment subsidized salt marshes are functionally equivalent to natural marshes, we examined above- and belowground primary production in replicated restored marshes receiving four levels of sediment addition (29-42 cm North American Vertical Datum of 1988 [NAVD 88]) and in degraded and natural ambient marshes (4-22 cm NAVD 88). Moderate intensities of sediment-slurry addition, resulting in elevations at the mid to high intertidal zone (29-36 cm NAVD 88), restored ecological function to degraded salt marshes. Sediment additions significantly decreased flood duration and frequency and increased bulk density, resulting in greater soil drainage and redox potential and significantly lower phytotoxic sulfide concentrations. However, ecological function in the restored salt marsh showed a sediment addition threshold that was characterized by a decline in primary productivity in areas of excessive sediment addition and high elevation (>36 cm NAVD 88). Hence, the addition of intermediate levels of sediment to submerging salt marshes increased marsh surface elevation, ameliorated impacts of prolonged inundation, and increased primary productivity. However, too much sediment resulted in diminished ecological function that was equivalent to the submerged or degraded system. ?? 2010 Society for Ecological Restoration International.

Impingement of Water Droplets on NACA 65A004 Airfoil and Effect of Change in Airfoil Thickness from 12 to 4 Percent at 4 deg Angle of Attack

NASA Technical Reports Server (NTRS)

Brun, Rinaldo J.; Gallagher, Helen M.; Vogt, Dorothea E.

1953-01-01

The trajectories of droplets in the air flowing past an NACA 65A004 a irfoil at an angle of attack of 4 deg were determined. The amount of water in droplet form impinging on the airfoil, the area of droplet impingement, and the rate of droplet impingement per unit area on the airfoil surface were calculated from the trajectories and presented to cover a large range of flight and atmospheric conditions. The effect of a change in airfoil thickness from 12 to 4 percent at 4 deg angle of attack is presented by comparing the impingement calculations for the NACA 65A004 airfoil with those for the NACA 65(sub 1)-208 and 65(sub 1)-212 airfoils. The rearward limit of impingement on the upper surface decreases as the airfoil thickness decreases. The rearward limit of impingement on the lower surface increases with a decrease in airfoil t hickness. The total water intercepted decreases as the airfoil thickness is decreased.

A pressure flux-split technique for computation of inlet flow behavior

NASA Technical Reports Server (NTRS)

Pordal, H. S.; Khosla, P. K.; Rubin, S. G.

1991-01-01

A method for calculating the flow field in aircraft engine inlets is presented. The phenomena of inlet unstart and restart are investigated. Solutions of the reduced Navier-Stokes (RNS) equations are obtained with a time consistent direct sparse matrix solver that computes the transient flow field both internal and external to the inlet. Time varying shocks and time varying recirculation regions can be efficiently analyzed. The code is quite general and is suitable for the computation of flow for a wide variety of geometries and over a wide range of Mach and Reynolds numbers.

Phycocyanin stability in microcapsules processed by spray drying method using different inlet temperature

NASA Astrophysics Data System (ADS)

Purnamayati, L.; Dewi, EN; Kurniasih, R. A.

2018-02-01

Phycocyanin is natural blue colorant which easily damages by heat. The inlet temperature of spray dryer is an important parameter representing the feature of the microcapsules.The aim of this study was to investigate the phycocyanin stability of microcapsules made from Spirulina sp with maltodextrin and κ-Carrageenan as the coating material, processed by spray drying method in different inlet temperature. Microcapsules were processed in three various inlet temperaturei.e. 90°C, 110°C, and 130°C, respectively. The results indicated that phycocyanin microcapsule with 90°C of inlet temperature produced the highest moisture content, phycocyanin concentration and encapsulation efficiency of 3,5%, 1,729% and 29,623%, respectively. On the other hand, the highest encapsulation yield was produced by 130°C of theinlet temperature of 29,48% and not significantly different with 110°C. The results of Scanning Electron Microscopy (SEM) showed that phycocyanin microcapsules with 110°C of inlet temperature produced the most rounded shape. To sum up, 110°C was the best inlet temperature to phycocyanin microencapsulation by the spray dryer.

Maintaining network activity in submerged hippocampal slices: importance of oxygen supply.

PubMed

Hájos, Norbert; Ellender, Tommas J; Zemankovics, Rita; Mann, Edward O; Exley, Richard; Cragg, Stephanie J; Freund, Tamás F; Paulsen, Ole

2009-01-01

Studies in brain slices have provided a wealth of data on the basic features of neurons and synapses. In the intact brain, these properties may be strongly influenced by ongoing network activity. Although physiologically realistic patterns of network activity have been successfully induced in brain slices maintained in interface-type recording chambers, they have been harder to obtain in submerged-type chambers, which offer significant experimental advantages, including fast exchange of pharmacological agents, visually guided patch-clamp recordings, and imaging techniques. Here, we investigated conditions for the emergence of network oscillations in submerged slices prepared from the hippocampus of rats and mice. We found that the local oxygen level is critical for generation and propagation of both spontaneously occurring sharp wave-ripple oscillations and cholinergically induced fast oscillations. We suggest three ways to improve the oxygen supply to slices under submerged conditions: (i) optimizing chamber design for laminar flow of superfusion fluid; (ii) increasing the flow rate of superfusion fluid; and (iii) superfusing both surfaces of the slice. These improvements to the recording conditions enable detailed studies of neurons under more realistic conditions of network activity, which are essential for a better understanding of neuronal network operation.

Quasi 1D Modeling of Mixed Compression Supersonic Inlets

NASA Technical Reports Server (NTRS)

Kopasakis, George; Connolly, Joseph W.; Paxson, Daniel E.; Woolwine, Kyle J.

2012-01-01

The AeroServoElasticity task under the NASA Supersonics Project is developing dynamic models of the propulsion system and the vehicle in order to conduct research for integrated vehicle dynamic performance. As part of this effort, a nonlinear quasi 1-dimensional model of the 2-dimensional bifurcated mixed compression supersonic inlet is being developed. The model utilizes computational fluid dynamics for both the supersonic and subsonic diffusers. The oblique shocks are modeled utilizing compressible flow equations. This model also implements variable geometry required to control the normal shock position. The model is flexible and can also be utilized to simulate other mixed compression supersonic inlet designs. The model was validated both in time and in the frequency domain against the legacy LArge Perturbation INlet code, which has been previously verified using test data. This legacy code written in FORTRAN is quite extensive and complex in terms of the amount of software and number of subroutines. Further, the legacy code is not suitable for closed loop feedback controls design, and the simulation environment is not amenable to systems integration. Therefore, a solution is to develop an innovative, more simplified, mixed compression inlet model with the same steady state and dynamic performance as the legacy code that also can be used for controls design. The new nonlinear dynamic model is implemented in MATLAB Simulink. This environment allows easier development of linear models for controls design for shock positioning. The new model is also well suited for integration with a propulsion system model to study inlet/propulsion system performance, and integration with an aero-servo-elastic system model to study integrated vehicle ride quality, vehicle stability, and efficiency.

On the question of starting conditions for frontal axisymmetric inlets tested in hot-shot wind tunnels

NASA Astrophysics Data System (ADS)

Gounko, Yu. P.; Mazhul, I. I.

2017-05-01

The work presents the results of an analysis of starting conditions for some frontal axisymmetric inlets of internal compression tested at freestream Mach numbers M = 3-8.4 in the hot-shot wind tunnels based at Khristianovich Institute of Theoretical and Applied Mechanics (ITAM). The results of these inlets test are compared with the data of numerical computations of inviscid, laminar, and turbulent flows carried out by the pseudo-unsteady method. There were determined the inlet throat areas limiting either with regard to the inlet starting or with regard to providing the maximally possible degree of geometric compression of the inlet-captured supersonic airstream at its deceleration in the already started inlet. Reshaping of computed flow patterns in the inlets depending on the variation of the minimal cross section of the inlet internal duct is analyzed.

[Antimicrobial activity of Laetiporus sulphureus strains grown in submerged culture].

PubMed

Ershova, E Iu; Tikhonova, O V; Lur'e, L M; Efremenkova, O V; Kamzolkina, O V; Dudnik, Iu V

2003-01-01

Cultural conditions for growth and fruit body formation were elaborated to four strains of Laetiporus sulphureus isolated from nature. All strains demonstrated antimicrobial activity against a wide spectrum of gram-positive and gram-negative bacteria during agar and submerged cultivation including methicillin-resistant strain of Staphylococcus aureus (MRSA) and glycopeptide-resistant strain of Leuconostoc mesenteroides. Antifungal activity was not found. The level of antimicrobial activity during submerged cultivation reached maximum after seven days of growth on specific medium with soybean meal and corn liquid; the next four weeks its increasing was not so manifested. Antimicrobial activity correlated with orange pigment secretion and cultural liquid acidification to pH 2.0-2.8 that indicates on acid nature of synthesized products.

Effect of inlet cone pipe angle in catalytic converter

NASA Astrophysics Data System (ADS)

Amira Zainal, Nurul; Farhain Azmi, Ezzatul; Arifin Samad, Mohd

2018-03-01

The catalytic converter shows significant consequence to improve the performance of the vehicle start from it launched into production. Nowadays, the geometric design of the catalytic converter has become critical to avoid the behavior of backpressure in the exhaust system. The backpressure essentially reduced the performance of vehicles and increased the fuel consumption gradually. Consequently, this study aims to design various models of catalytic converter and optimize the volume of fluid flow inside the catalytic converter by changing the inlet cone pipe angles. Three different geometry angles of the inlet cone pipe of the catalytic converter were assessed. The model is simulated in Solidworks software to determine the optimum geometric design of the catalytic converter. The result showed that by decreasing the divergence angle of inlet cone pipe will upsurge the performance of the catalytic converter.

Coupled Analysis of an Inlet and Fan for a Quiet Supersonic Aircraft

NASA Technical Reports Server (NTRS)

Chima, Rodrick V.; Conners, Timothy R.; Wayman, Thomas R.

2009-01-01

A computational analysis of a Gulfstream isentropic external compression supersonic inlet coupled to a Rolls-Royce fan was completed. The inlet was designed for a small, low sonic boom supersonic vehicle with a design cruise condition of M = 1.6 at 45,000 feet. The inlet design included an annular bypass duct that routed flow subsonically around an engine-mounted gearbox and diverted flow with high shock losses away from the fan tip. Two Reynolds-averaged Navier-Stokes codes were used for the analysis: an axisymmetric code called AVCS for the inlet and a 3-D code called SWIFT for the fan. The codes were coupled at a mixing plane boundary using a separate code for data exchange. The codes were used to determine the performance of the inlet/fan system at the design point and to predict the performance and operability of the system over the flight profile. At the design point the core inlet had a recovery of 96 percent, and the fan operated near its peak efficiency and pressure ratio. A large hub radial distortion generated in the inlet was not eliminated by the fan and could pose a challenge for subsequent booster stages. The system operated stably at all points along the flight profile. Reduced stall margin was seen at low altitude and Mach number where flow separated on the interior lips of the cowl and bypass ducts. The coupled analysis gave consistent solutions at all points on the flight profile that would be difficult or impossible to predict by analysis of isolated components.

Coupled Analysis of an Inlet and Fan for a Quiet Supersonic Jet

NASA Technical Reports Server (NTRS)

Chima, Rodrick V.; Conners, Timothy R.; Wayman, Thomas R.

2010-01-01

A computational analysis of a Gulfstream isentropic external compression supersonic inlet coupled to a Rolls-Royce fan has been completed. The inlet was designed for a small, low sonic boom supersonic vehicle with a design cruise condition of M = 1.6 at 45,000 ft. The inlet design included an annular bypass duct that routed flow subsonically around an engine-mounted gearbox and diverted flow with high shock losses away from the fan tip. Two Reynolds-averaged Navier-Stokes codes were used for the analysis: an axisymmetric code called AVCS for the inlet and a three dimensional (3-D) code called SWIFT for the fan. The codes were coupled at a mixing plane boundary using a separate code for data exchange. The codes were used to determine the performance of the inlet/fan system at the design point and to predict the performance and operability of the system over the flight profile. At the design point the core inlet had a recovery of 96 percent, and the fan operated near its peak efficiency and pressure ratio. A large hub radial distortion generated in the inlet was not eliminated by the fan and could pose a challenge for subsequent booster stages. The system operated stably at all points along the flight profile. Reduced stall margin was seen at low altitude and Mach number where flow separated on the interior lips of the cowl and bypass ducts. The coupled analysis gave consistent solutions at all points on the flight profile that would be difficult or impossible to predict by analysis of isolated components.

Predicting tidal marsh survival or submergence to sea-level rise using Holocene data

NASA Astrophysics Data System (ADS)

Horton, B.; Shennan, I.; Bradley, S.; Cahill, N.; Kirwan, M. L.; Kopp, R. E.; Shaw, T.

2017-12-01

Rising sea level threatens to permanently submerge tidal marsh environments if they cannot accrete faster than the rate of relative sea-level rise (RSLR). But regional and global model simulations of the future ability of marshes to maintain their elevation with respect to the tidal frame are uncertain. The compilation of empirical data for tidal marsh vulnerability is, therefore, essential to address disparities across these simulations. A hitherto unexplored source of empirical data are Holocene records of tidal marsh evolution. In particular, the marshes of Great Britain have survived and submerged while RSLR varied between -7.7 and 15.2 mm/yr, primarily because of the interplay between global ice-volume changes and regional isostatic processes. Here, we reveal the limits to marsh vulnerability are revealed through the analysis of over 400 reconstructions of tidal marsh submergence and conversion to tidal mud flat or open water from 54 regions in Great Britain during the Holocene. Holocene records indicate a 90% probability of tidal marsh submergence at sites with RSLR exceeding 7.3 mm/yr (95% CI: 6.6-8.6 mm/yr). Although most modern tidal marshes in Great Britain have not yet reached these sea-level rise limits, our empirical data suggest widespread concern over their ability to survive rates of sea-level rise in the 21st century under high emission scenarios. Integrating over the uncertainties in both sea-level rise predictions and the response of tidal marshes to sea-level rise, all of Great Britain has a >80% probability of marsh submergence under RCP 8.5 by 2100, with areas of south and eastern England, where the rate of RSLR is increased by glacio-isostatic subsidence, achieving this probability by 2040.

The role of submerged trees in the early development of fishes in a Neotropical reservoir.

PubMed

Gogola, T M; Daga, P S; Gubiani, É A; da Silva, P L R; Sanches, P V

2016-07-01

It was hypothesized that the structural heterogeneity provided by submerged trees positively favours the spatial distribution of fish abundance at early stages of development in an area under the influence of a Neotropical reservoir in the Paraná River basin. The distribution at early stages of development of the most abundant species was evaluated. To remove any possible confounding effect related to local environmental variables, changes in these were also evaluated. Sampling was carried out at sites with and without submerged trees. Among all individuals sampled, 96·1% were classified as larvae and 3·9% as juveniles. The area without submerged trees showed higher total abundance, but there were spatial differences in the distribution of early stage fishes. From the moment the larvae are able to swim actively, they search for sites with a complex structure. The results show that reaches with submerged trees play an important role in the early development of fishes in reservoirs, and, hence, the preservation of those trees is essential to maintain biodiversity in reservoirs. © 2016 The Fisheries Society of the British Isles.