... accurate approximation for dilute mixtures of gas bubbles in a liquid. ... Keywords: Sound speed; Bubbly liquids; Wood's equation; Two phase media. ...

In order to accurately model the two phase portion of a pressure vessel blowdown, it becomes necessary to understand the bubble growth mechanism within the vessel during the early period of the decompression, the two phase flow behavior within the vessel,...

Accurate simulation of variably saturated flows can be difficult for many reasons. Soil properties often vary greatly over the problem domain. The underlying balance equations are highly nonlinear, and solutions may develop sharp fronts at the scale of interest. It is clear that straightforward application of standard Galerkin finite element methodologies is inadequate for ...

... fell approximately as would be expected from the analysis. ... conclusion that an annular or stratified annular flow ... for a type of horizontal capillary slug ...

There will be approximately two phases of testing: arm sweep analysis to be performed in the Anthropometry and Biomechanics Facility (ABF), and torso lean ...

The transport of cesium through a tungsten capillary occurs through two phases, an adsorbed layer and a vapor. In this analysis these two phases are connected by the experimentally observed relationship, rather than by an linearized approximation to it. T...

We are interested in the numerical approximation of two-fluid models of nonequilibrium two-phase flows described by six balance equations. We introduce an original splitting technique of the system of equations. This technique is derived in a way such tha...

An accurate prediction of transient two-phase flow is essential to safety analyses of nuclear reactors under accident conditions. The fluid flow and heat transfer encountered are often extremely complex due to the reactor geometry and occurrence of transient two-phase flow. Recently considerable progresses in understanding and ...

During an acute viral infection, virus levels rise, reach a peak and then decline. Data and numerical solutions suggest the growth and decay phases are linear on a log scale. While viral dynamic models are typically nonlinear with analytical solutions difficult to obtain, the exponential nature of the solutions suggests approximations can be found. We derive a two-phase ...

A mixture fraction formulation to perform direct numerical simulations of a disperse and dilute two-phase system consisting of water liquid and vapor in air in local thermodynamic equilibrium using a two-fluid model is derived and discussed. The goal is to understand the assumptions intrinsic to this simplified but commonly employed approach for the study of two-layer buoyancy ...

Detection of small faults is one of the most important and challenging tasks in the area of fault diagnosis. In this paper, we present an approach for the rapid detection of small oscillation faults based on a recently proposed deterministic learning (DL) theory. The approach consists of two phases: the training phase and the test phase. In the training ...

... SUBJECT TERMS interior ballistics, primer, CFD, two-phase ... modeling of the mortar launch is to ... to coincide with the approximate length covered by ...

Two phase thermal and dynamic fluid flow models of the IPSTB were built to ... the IPSTB and its approximately 600 channels of system instrumentation would ...

Flow regime transitions and the modeling thereof underlie the design of microgravity two-phase systems. Through the use of the zero-g laboratory, microgravity two-phase flows can be studied. Because microgravity two-phase flows exhibit essentially no accelerations (i.e. no buoyancy or gravitational forces), the effects of acceleration ...

The potential influence of gas bubbles on the viscosity of molten coal at elevated temperatures was estimated by calculations, using literature models for the viscosity of two and three phase suspensions. In one approach, gas bubbles in molten coal were approximated as the dispersed phase of deformable liquid globules in G.I. Taylor`s model of emulsion viscosity. This model ...

The potential influence of gas bubbles on the viscosity of molten coal at elevated temperatures was estimated by calculations, using literature models for the viscosity of two and three phase suspensions. In one approach, gas bubbles in molten coal were approximated as the dispersed phase of deformable liquid globules in G.I. Taylor's model of emulsion viscosity. This ...

An ill-posed Cauchy problem for a model of a nonequilibrium two-phase flow in the barotropic approximation is transformed into a well-posed problem by changing the type of the initial hyperbolic equations. Approximation of fluctuations of the phase velocities by a random delta-correlated process and averaging of the equations over its ...

The Debye equation with slit-smeared small angle x-ray scattering (SAXS) data is extended from an ideal two-phase system to a pseudo two-phase system with the presence of the interface layer, and a simple accurate solution is proposed to determine the average thickness of the interface layer in porous materials. This method is tested ...

The local flow structure occurring inside two-phase mixers liquid-metal magnetohydrodynamic (LMMHD) mixers and generators was investigated to determine the relation between the characteristics of local two-phase flow structure at high void fractions (approximately 0.6 to approximately 0.9) and LMMHD power ...

The diagnostic findings of the radioiodine two-phase uptake can be increased considerably by changing loads of thyroid hormone or thyrotropic pituitary hormone. The reciprocity between hypophysis and thyroid gland can be ana lyzed more accurately by this method. The determination of the so-called speed index allows further conclusion not only ...

A procedure for numerical simulation of the steady, two-phase vibrationally unequilibrated flow in a mixing gasdynamic laser working on a mixture of CO2-N2-H2O-O2 and Al2O3 particles (generated by combustion of aluminum in air) is described. The one-dimensional approximation is used. One assumes instantaneous mixing of the components in a specific nozzle ...

An alternative to currently used two-phase flow equations is considered to resolve discontinuous solutions in gas-solid mixtures. The equations in the present paper are based on the theory of thermodynamically compatible systems of hyperbolic conservation laws. The conservative hyperbolic governing equations were solved using Godunov methods of centred-type. This solution is ...

The design of efficient heat exchangers in which the working fluid changes phase requires accurate modeling of two-phase fluid flow. The local Navier-Stokes equations form the basic continuum equations for this flow situation. However, the local instantan...

The core of the approach is an accurate, flexible, and powerful CFD code ... Grid definition: MaxS/PATRAN/FLUENT/STEP (any source). " Boundary layer: CFD to ...

New measuring methods are developed and are tested with the small reactor simulator MIDAS (Mini Dodewaard ASsembly). The purpose of this work is to be able to measure accurately as many different properties of the flow as possible in the bigger simulator ...

A novel method for computing two-phase relative permeability curves from the results of spontaneous imbibition experiments is presented. Using a specially constructed imbibition cell and an X-ray Computed Tomography (CT) scanner, we obtain accurate measur...

This final report describes the initial two phases of the overall project. In the first phase, accurate barriers and energetics were calculated for 7 reactions involved in O(3P) oxidation of hydrocarbons. This was done by MRCI/CASSCF ab initio calculation...

Mechanical properties of two phase materials, such as strength, ductility and toughness, depend on the size and distribution of the second phase. However, no methods are presently available to accurately quantify the homogeneity of the distribution of the...

The need for a quick and accurate means of analysing combustion products and other gases resulted in the decision to acquire some modern equipment. After surveying the equipment on the market two phase-sep LC-2 gas chromatographs were obtained from Jones ...

Page 1. Accurate Approximations for European-Style Asian Options ... Let W+ be the final payoff of a European style Asian (call or put) option. ...

We have measured and modeled the change in electrical resistivity due to partial transformation to the martensitic {alpha}{prime}-phase in a {delta}-phase Pu-Ga matrix. The primary objective is to relate the change in resistance, measured with a 4-probe technique during the transformation, to the volume fraction of the {alpha}{prime} phase created in the microstructure. Analysis by finite element ...

... within the limits of the approximations to which (l.1 ... be determined to a first approximation by the ... local intensity of the distorted wave (more accurately ...

... that the approximations are sufficiently accurate, making them useful as tools to aid in the design of electrically short cylindrical monopoles over a ...

Advanced modeling techniques have been combined with modern, special-purpose peripheral minicomputer technology to develop a plant analyzer which provides realistic and accurate predictions of plant transients and severe off-normal events in nuclear power plants through on-line simulations at speeds of approximately 10 times faster than actual process ...

For composites with a lightly hardening matrix, work hardening occurs whenever primary slip regions are inhibited from developing. Elastic inclusions impose approximately the same restrictions as rigid inclusions on the internal deformation of the matrix....

J.A. Boure, Centre d'Etudes Nucleaires de Grenoble. Two-Phase. Potential Flow ..... from the approximate dispersion equation (Bourn, 1988b) ...... Wigner- Seitz bubble, has two fundamental properties. Firstly, ...

The question of how to assess bioavailability has received much attention. Bioavailabilty is most often approximated by the distribution of the solute in question between two phases, most often bulk phases, of water and an immiscible organic solvent. Sinc...

A two phase study was conducted to determine the effect on the braking performance of light vehicles of installing aftermarket brake linings. In Phase I approximately 300 in-use vehicles (passenger cars and pickup trucks) were rented from consumers and te...

A numerical procedure is derived for the solution of the Vlasov-Poisson system of equations in two phase-space variables. Derivatives with respect to the phase-space variables are approximated by a weighted sum of the values of the distribution function a...

The purpose of the report is to present a user's description of the fracture reservoir model ''FRACT 2-2''. A numerical model for obtaining an approximate solution of the governing equations of two phase flow in naturally fractured reservoir has been cons...

... The concentration of oxygen calculated from ultrasonic data is accurate to approximately 1% over the range of 21 to 95%. ...

... Title : ANALYTIC SOLUTIONS TO THE EQUATIONS OF MOTION ... very accurately by the approximate solutions. An alternate solution for the modal ...

Equation systems describing one-dimensional, transient, two-phase flow with separate continuity, momentum, and energy equations for each phase are classified by use of the method of characteristics. Little attempt is made to justify the physics of these equations. Many of the equation systems possess complex-valued characteristics and hence, according to well-known ...

Performance characteristics of Loss-of-Fluid Test (LOFT) reactor coolant pumps under transient two-phase flow conditions were obtained based on the analysis of two large and small break loss-of-coolant experiments conducted at the LOFT facility. Emphasis is placed on the evaluation of the transient two-phase flow effects on the LOFT reactor coolant pump ...

A numerical solution procedure was developed for solving one phase, gas-only flow or fully coupled, gas-particle two phase flow in axisymmetric or two-dimensional geometries. The numerical basis of the research is a time-dependent, unsplit, second-order accurate MacCormack finite difference scheme. Some special numerical techniques are ...

Typically, multiphase modeling begins with an averaged (or homogenized) system of partial differential equations (traditionally ill-posed) then discretizes this system to form a numerical scheme. Assuming that the ill-posedness problem is avoided by using a well-posed formulation such as the seven-equation model, this presents problems for the numerical approximation of ...

The particle image velocimetry has been developed to measure the typical two-phase flow of various work conditions in Membrane Micropore Aeration Bioreactor. The fluid phase is separated out using image processing techniques, which provided accurate measurements for the Bioreactor�s flow field, and makes it possible for quantitative analysis of the ...

In this paper a mathematical model for densely loaded particle-laden flows is proposed to account for particle collisions and particle-turbulence interaction. The coupled conservation equations are based on a Eulerian scheme for the gas and a stochastic Lagrangian technique for the particles. The model was validated against the experimental data of densely loaded particle-laden jet flows. The ...

An improved particle tracking (PTV) system has been developed at the Texas A and M Department of Nuclear Engineering for making two-phase flow measurements. Improvements include a more powerful Nd:YAG pulsed laser, a new high-resolution digital camera, and updated particle tracking software. These improvements significantly enhance the quality and amount of turbulence data ...

In order to accurately model the two phase portion of a pressure vessel blowdown, it becomes necessary to understand the bubble growth mechanism within the vessel during the early period of the decompression, the two phase flow behavior within the vessel, and the applicability of the ...

The Zn-Sc-Fe icosahedral quasicrystal and its 1/1 crystal approximant have been studied with 57Fe M�ssbauer spectroscopy at room temperature. The spectra for the two phases exhibit substantially different features, indicating largely different local atomic environments in the two phases. This ...

Accurate numerical methods for treating the junction and boundary conditions needed in the transient two-phase flows of a piping network were published earlier by us; the same methods are used to formulate the treatment of the material interface as a moving boundary. The method formulated is used in a computer program to calculate sample problems designed ...

of linear molecules, at least approximately. Accurate a priori calculation of relaxation times requires an accurate knowledge of the molecular phrenology, ...

Since the inception of the development of a two-phase liquid-metal magnetohydrodynamic (LMMHD) power generation system at Argonne National laboratory over a decade ago (Petrick and Lee, 1964), increasing emphasis has been placed on the relation between the characteristics of local two-phase flow structure at high void fractions (approximately 0.6 to ...

The ultimate objective of the Sandia Labs Program on two-phase jet loads is to develop an approximate engineering model characterizing two-phase jets emanating from circumferential or longitudinal breaks in a typical PWR piping system. Most of the work performed to date has focused on this second task. Three computer codes have been employed to investigate ...

We present real-time observations of a new growth pattern called a spiral two-phase dendrite, which we observed during univariant directional solidification of a ternary-eutectic alloy. Two different crystal phases grow from the apex of a parabolic finger, forming a spiral pattern that leaves behind in the solid a double helix microstructure. The parabola tip radius is nearly ...

The steady-state approximation is commonly used in enzyme catalysis kinetics calculations, but how much error does the approximation introduce? This Java applet allows you to visually determine the accuracy of the steady-state and pre-equilibrium approximations.

A stable recursive algorithm which approximates mean queue size (state probability) for the M/G/c queue is considered. Using this particular approximation for the queue size distribution, an accurate approximation for the waiting time distribution is deve...

Errors resulting from two approximations of the transmission line parameters of overhead wires are determined. Sunde's simple approximation is found to be more accurate than the Handel function approximation.

Off-the-shelf CFD software is being used to analyze everything from flow over airplanes to lab-on-a-chip designs. So, how accurately can two-phase immiscible flow be modeled flowing through some small-scale models of porous media? We evaluate the capability of the CFD code FLUENT{trademark} to model immiscible flow in micro-scale, bench-top ...

Water displacement methods are commonly used to measure upper limb swelling. The purpose of this study was to improve upon currently used volumetric equipment and methods by developing a volumetric method that would be reliable, accurate, and sensitive to changes in forearm and hand volume of less than 1%. The first two phases involved ...

The (2+1)-dimensional Gross-Neveu model is analyzed by the Gaussian approximation in the functional Schroedinger picture. It is shown that the Gaussian effective potential implies the existence of two phases, and one of them is inconsistent. In the phase where the bare coupling constant approaches positive infinitesimal, the effective ...

some of the individual effects. (e.g., two phase flow modeling, high Knudsen number ... seal approximation'. (analogous to the narrow bearing approximation) ... seals, lubricant cavitation is possible due to hydrodynamic effects. This has been experimentally ..... a few different designs and found that the ...

Accurate calculation of surface tension force is critically important for numerical simulation of gas-liquid two-phase flows at small capillary number. It is well known that the errors in the surface tension calculation would cause considerable parasitic flow with conventional continuum surface force method. In the present simulation, Phase-Field method is ...

In the line of previous work done at CEA Grenoble, large size experiments were performed with the support of CERN for the validation of the LHC two phase superfluid helium cooling scheme. In order to be as close as possible to the real configuration, a straight, inclinable 22 m long line of 40 mm I.D. was built. Very accurate ...

Optical heterodyning, also know as photomixing is an attractive solution as a single device able to cover the entire frequency range from 300 GHz to 3 THz. As the THz frequency is extracted from the difference frequency of two lasers, the accuracy with which the generated frequency is known is directly determined by the frequency accuracy of the lasers. In order to fully characterize the spectral ...

This report summarizes the work on the research project on this cooperative program between DOE and Hitachi, Ltd. Major advances were made in the computational reconstruction of images from electrical excitation and response data with respect to existing capabilities reported in the literature. A demonstration is provided of the imaging of one or more circular objects within the measurement plane ...

This paper will present a high fidelity solution algorithm for a model of a nuclear reactor core barrel. This model consists of a system of nine nonlinearly coupled partial differential equations. The coolant is modeled with the 1-D six-equation two-phase flow model of RELAP5. Nonlinear heat conduction is modeled with a single 2-D equation. The fission power comes from two 2-D ...

Conditional inference plays a central role in statistics, but determination of relevant conditional distributions is often difficult. We develop analytical procedures that are accurate and easy to apply for approximating conditional distribution functions...

In high-temperature and high-pressure experiments, known equations of state (EOS) of standard materials, such as NaCl, MgO, Au, and Pt, or the ruby-fluorescence pressure scale are generally used to measure pressure in the systems concerned. However, severe discrepancies are reported between proposed pressure scales especially at high temperatures, and thus critical crosschecks on these pressure ...

Coriolis meter, despite being very accurate in single phase conditions, fails to accurately measure two-phase flows. It poses a complex fluid-structure interaction problem in case of two-phase operation; there is a scarcity of theoretical models available to predict the errors reported by Coriolis meter in aforementioned conditions, ...

A method for accurately approximating T-matrix elements in atom-diatom collisions is presented. Calculations are given for hydrogen helium collisions. (AIP)

We consider a standard model for incompressible two-phase flows in which a localized force at the interface describes the effect of surface tension. If a level set (or VOF) method is applied then the interface, which is implicitly given by the zero level of the level set function, is in general not aligned with the triangulation that is used in the discretization of the flow ...

Please ensure that all information is complete and accurate. Falsification of University documents necessary. #12;Please ensure that all information is complete and accurate. Falsification of University information is complete and accurate. Falsification of University documents may warrant corrective action

The construction and the analysis of nonoscillatory shock capturing methods for the approximation of

CFL3D is an implicit code and employs approximate factorization, ... earization and factorization errors. The more sub-iterations performed, ...

... on a simple optimization algorithm are included. 37 ... load approximation techniques based on the ... enable the computationally efficient and accurate ...

The development of high-order accurate numerical discretization techniques for irregular domains and

... It should therefore be possible to approximate the solution accurately using the Rayleigh-Ritz Galerkin method with a piecewise polynomial ...

... Abstract : The use of piecewise cubic Hermite polynomials to approximate resonance region cross sections provides a means to accomplish the ...

An accurate approximation to this criterion is further shown to be that the ... 1999: Criterion for the dynamical stability of a non-adiabatic spherical ...

... obtained. This method is almost as accurate as the simpli- fied set of equations above, except for time-of-flight calculations. It ...

... obtained. This method is almost as accurate as the simplified set of equations above, except for time-of-flight calculations. It ...

... to analyze and compare the atmospheric radiative fluxes and cooling ... is more accurate for the upward fluxes. ... divergence of the net flux is extremely ...

The method is based upon molecular line parameters and makes use of a far wing scaling approximation

... This paper models the equilibrium solutions for a laser ... the peak density, velocity, and temperature of the ... and the distance to the critical surface on ...

This report examines the pressure drop and heat transfer characteristics of two-phase micro-channel heat sinks. New models and correlations are proposed for both saturated and subcooled boiling conditions. These tools are shown to provide accurate predict...

This report examines the pressure drop and heat transfer characteristics of two-phase micro-channel heat sinks. New models and correlations are proposed for both saturated and subcooled boiling conditions. These tools are shown to provide accurate predict...

... two-fluid models for bubbly two-phase flow to accurately predict lateral phase distribution phenomena in microgravity environments. If ... We assume the following form of the interfacial drag law: ... between the continuous phase and the dispersed bubbles. .... Figure-10 Measurement of local volume fraction of ...

It has long been known that the shock induced {alpha} to {epsilon} phase transition in iron exhibits significant metastability in the two phase region above 13 GPa. The authors have developed a simple, physically motivated model that accurately describes the metastable phase transition surface for shock loaded iron during numerical ...

Nanofluids are a new class of fluids engineered by dispersing nanometer-size solid particles in base fluids. As a new research frontier, nanofluid two-phase flow and thermal physics have the potential to improve heat transfer and energy efficiency in thermal management systems for many applications, such as microelectronics, power electronics, transportation, nuclear ...

An exponential approximation for the M/M/1 busy period probability density is derived by entropy maximization and studied numerically. The approximation is accurate for light loads: For load factors less than about .1, the approximation is accurate to wit...

, an accurate calculation of the solvent-accessible surface area (SASA), a geometric measure of this exposure-atom representation of the molecule. This manuscript introduces a series of four SASA approximations of increasing on these SASA approximations. Their ability to distinguish correctly from incorrectly folded protein models

The object was to establish a full experimental correlation between flashing flows of water-steam in actual geothermal wells and flashing flows of refrigerant-114 (R-114) in the Brown University/DOE Two-Phase Flow Facility. Our experiments show that the similarity theory developed in our laboratory during previous phases of this research project can be used to predict ...

The overall object was to establish a full experimental correlation between flashing flows of water-steam in actual geothermal wells and flashing flows of refrigerant-114 (R-114) in the Brown University/DOE Two-Phase Flow Facility. Our experiments show that the similarity theory developed in our laboratory during previous phases of this research project can be used to predict ...

The overall object was to establish a full experimental correlation between flashing flows of water-steam in actual geothermal wells and flashing flows of refrigerant-114 (R-114) in the Brown University/DOE Two-Phase Flow Facility. Our experiments show that the similarity theory developed in our laboratory during previous phases of this research project can be used to predict ...

The steam generator (SG) in a pressurized water reactor (PWR) is an important component as boundary between the primary loop and the secondary loop. In this study, we performed two-phase flow analysis of SG reliability tests conducted by the Nuclear Power Engineering Corporation (NUPEC) using the two-fluid models of a thermal-hydraulic computer code PHOENICS. It was difficult ...

We develop a thermodynamically consistent mixture model for avascular solid tumor growth which takes into account the effects of cell-to-cell adhesion, and taxis inducing chemical and molecular species. The mixture model is well-posed and the governing equations are of Cahn�Hilliard type. When there are only two phases, our asymptotic analysis shows that ...

Wire mesh sensors (WMS) are fast imaging instruments that are used for gas-liquid and liquid-liquid two-phase flow measurements and experimental investigations. Experimental tests were conducted at Helmholtz-Zentrum Dresden-Rossendorf to test both the capacitance and conductance WMS against a gamma densitometer (GD). A small gas-liquid test facility was utilized. This ...

Founded in 1889, Slippery Rock University (SRU) is a state university with 8,500 students and 400 faculty. Facilities and planning (F&P) employs 178 staff, of which 50 are custodians. F&P is responsible for the maintenance of 560 acres and 60 major buildings that comprise approximately 2.3 million gross square feet. Currently work is assigned to the custodians, by two ...

The purpose of this study was to find if direct ophthalmoscopy, a simple technique, could be used to give an approximate value of the refractive correction for a patient. This would shorten the time and lessen the effort to be expended during the following retinoscopic examination done for finding the patient's refractive correction. The use of direct ophthalmoscopy for this ...

In cooling sintered composites of Al[sub 2]O[sub 3]-ZrO[sub 2] from their fabrication temperature residual stresses are created as a result of both the difference in thermal expansion between the two phases and the crystallographically anisotropic thermal expansion of the Al[sub 2]O[sub 3] phase. In this work the first and second moments of the residual ...

We develop a thermodynamically consistent mixture model for avascular solid tumor growth which takes into account the effects of cell-to-cell adhesion, and taxis inducing chemical and molecular species. The mixture model is well-posed and the governing equations are of Cahn-Hilliard type. When there are only two phases, our asymptotic analysis shows that ...

Accurate estimation of the specific binding of (/sup 3/H)ouabain in intact tissues is difficult. Toxic actions of non-labeled ouabain at high concentrations is necessary to prevent specific binding of (/sup 3/H)ouabain to Na,K-ATPase caused a loss of cell viability and non-specific binding to be underestimated in these preparations. Dissociation of (/sup 3/H)ouabain from ...

In this work the theoretical basis for the famous formula of Macleod, relating the surface tension of a liquid in equilibrium with its own vapor to the one-particle densities in the two phases of the system, is derived. Using the statistical-mechanical definition of the surface tension, it is proved that this property is, at the first ...

We show that at difference from simple block-spin methods, a previously discussed hamiltonian variational approach is able to indicate the appearance of two phase transitions for the vector Potts spin model Z(N) in 1+1 dimensions and N approximately >5. (...

The process of melting and solidification in metal casting is considered. The process is modeled by a three-dimensional two-phase initial-boundary value problem of the Stefan type. The mathematical formulation of the problem and its finite-difference approximation are given. A numerical algorithm is presented for solving the direct problem. The results are ...

polar wander (APW) reaffirms that pre-drift recon- structions based on either continental outlinesGeophys. J. Int. (2003) 152, 68�78 Pre-drift extension of the Atlantic margins of North America in the two continental margins. Extension appears to have occurred in two phases of approximately equal

The purpose of the Mark 22 Flow Excursion Follow-On testing was to investigate the theory that approximately 15% of the flow bypassed the primary flow channels in previous testing, whereas the design called for only a 3% bypass. The results of the follow-on tests clearly confirmed this theory. The testing was performed in two phases. ...

. The above system models the two phase flow of an in- compressible fluid which has an interfacial energy E =E INTERFACE ENERGIES CAPTURING THE EULER NUMBER: RELAXATION AND RENOMALIZATION QIANG DU, CHUN LIU, ROLF RYHAM�, AND XIAOQIANG WANG� Abstract. We introduce a set of new interfacial energies for approximating the Euler number

An experimental and analytical investigation of liquid entrainment in annular two-phase flow for smooth and rifled tubes was performed. The analytical work involved the development of a simplified theoretical model to allow the accurate prediction of liquid-entrainment rates. This rate is expressed mathematically as the product of the fluid density and the ...

Predicting particle dispersion in recirculating two-phase flows is a key issue for reacting flows and a potential application of large eddy simulation (LES) methods. In this study, Euler/Euler and Euler/Lagrange LES approaches are compared in the bluff body configuration from Bor�e et al. [J. Bor�e, T. Ishima, I. Flour, The effect of mass loading and inter-particle ...

The combined effects of local power distribution and grid spacers on CHF were experimentally evaluated using an electrically heated 16 rod bundle simulation of a typical BWR fuel assembly. The single and two-phase hydraulic behavior of the test assembly was also evaluated. Data were obtained over a range of pressures (1000-1500 psia), mass velocities (0.5 x 10{sup 6} - 2.0 x 10{sup 6} lb/hr ft{sup ...

Materials with nanometer size heterogeneities are commonplace in the physical and biological sciences and often exhibit complex morphologies. Although this morphology has a dramatic effect on the materials' properties (e.g., transport and reaction processes), it is often difficult to accurately characterize. We describe a method, using a novel analysis of small angle ...

Laser-Doppler anemometry (LDA) was used to measure local mean axial velocities and turbulence intnsities at selected locations within a study model dimensionally protypic of an existing PWR steam generator design. The model tube bundle with support plate was installed in a special flow housing that formed part of an isothermal recirculating water flow loop. Flow conditions for this experiment were ...

Previously, we showed that the icosahedral quasicrystal Cd{sub 5.7}Yb possesses similar structural vacancies to those in its cubic 1/1-approximant Cd{sub 6}Yb by positron lifetime measurements [K. Sato, H. Uchiyama, K. Arinuma, I. Kanazawa, R. Tamura, T. Shibuya, and S. Takeuchi, Phys. Rev. B 66, 052201 (2002)]. In the present paper, the local chemical environment around the ...

In this dissertation we discuss some upscaling methods for flow and transport in heterogeneous reservoirs. We studied realization-based multi-phase flow and transport upscaling and ensemble-level flow upscaling. Multi-phase upscaling is more accurate than single-phase upscaling and is often required for high level of coarsening. In multi-phase upscaling, the upscaled transport ...

The design of efficient heat exchangers in which the working fluid changes phase requires accurate modeling of two-phase fluid flow. The local Navier-Stokes equations form the basic continuum equations for this flow situation. However, the local instantaneous model using these equations is intractable for afl but the simplest problems. AH the practical models for two-phase ...

Direct numerical simulation has been used to examine the near-field dynamics of annular gas-liquid two-phase jets. Based on an Eulerian approach with mixed fluid treatment, combined with an adapted volume of fluid method and a continuum surface force model, a mathematical formulation for the flow system is presented. The swirl introduced at the jet nozzle exit is based on ...

A coupled finite difference algorithm on rectangular grids is developed for viscoelastic ink ejection simulations. The ink is modeled by the Oldroyd-B viscoelastic fluid model. The coupled algorithm seamlessly incorporates several things: (1) a coupled level set-projection method for incompressible immiscible two-phase fluid flows; (2) a higher-order Godunov type algorithm for ...

The aim of this paper is to calculate the two-dimensional, nonequilibrium, two-phase flow in a de Laval nozzle and to compare it with the one-dimensional approximation. The following two types of a flow are considered in two nozzles of different shapes: (1) the pure water steam flow with a relative gas expansion rate of an order of magnitude of about ...

A new powerful experimental technique based on holographic observations, developed at the NASA Marshall Space Flight Center, now permits observation of small liquid droplets coarsening. This technique was developed and used for mixed-dimensional coarsening studies. Experiments were conducted on an isopycnic two-phase alloy of succinonitrile and water, annealed isothermally ...

Traditionally, in cold spray two-phase supersonic jet formed with the help of converging-diverging nozzle are used. In this study an alternative design of cold spray nozzle is proposed in which a high velocity two-phase flow is created using an intense flow swirling in a constant section barrel (cylinder) with double-edged bevel exit. As a result, a high ...

The attenuation of Longitudinal ultrasonic waves has been measured in single crystals of indium (99.999%) and of indium doped with 0.003 a % of tin in the intermediate state over the frequency range 10--30 MHz. Two phase have been identified in the superconducting layers. The fundamental frequency for one phase is approximately ...

Numerical solutions of the equations governing two-phase isentropic flow of a solid granular material dispersed in a gas are investigated. Both the dispersed and continuous phases are treated as continua and an Eulerian description of the flow is adopted. We present an inviscid model with a general pressure term from which a number of variant models can be obtained. A high ...

, a fairly accurate approximate expression for the cdf of the delivery delay is also derived and validated expression as well as a fairly accurate approximation are derived for the achieved delivery ratio. In Section of the original cdf. Based on the above observations, an approximate ...

by predicting a0 1%�2% bigger10 than the experiment. Predicting lattice constants more accurately than LSD to approximate EXC, starting with the local spin density LSD approxima- tion LDA , which is still widely used. The generalized gra- dient approximations3�5 GGAs are semilocal, seeking to improve upon LSD. Other more

Conserving approximations are applied to the attractive Holstein and Hubbard models (on an infinite-dimensional hypercubic lattice). All effects of nonconstant density of states and vertex corrections are taken into account in the weak-coupling regime. Infinite summation of certain classes of diagrams turns out to be a quantitatively less accurate ...

In this paper (a third in a series) the construction and the analysis of essentially non-oscillatory shock capturing methods for the approximation of hyperbolic conservation laws are presented. Also presented is a hierarchy of high order accurate schemes ...

A method for accurate measurement of complex parts that contain no reference points is described. The technique is applied to the production of accurate castings, to their machining, and to their installation. Accuracies of )approximately) 2 mil can be achieved over distances of 7 ft. 3 figs.

A method for accurate measurement of complex parts that contain no reference points is described. The technique is applied to the production of accurate castings, to their machining, and to their installation. Accuracies of /approximately/ 2 mil can be ac...

Saturated groundwater flow can often be described by the law of mass conservation and Darcy's law, i.e. by a potential flow problem. An accurate approximation of the specific discharge can be determined by the mixed finite element method. In this article ...

A simple yet highly accurate method for approximately calculating spectrum-averaged beta energies and beta spectra for radioactive nuclei is presented. This method should prove useful for users who wish to obtain accurate answers without complicated calcu...

Reactive flow systems often consist of multicomponent mixtures of neutral gases. Accurate modelling of reactive flows will, in many cases, require the accurate representation of transport phenomena in the conservation equations. In this paper, we identify...

Accurate hybrid stochastic simulation of a system of coupled chemical or biochemical reactions reactions, approximates the fast reactions as a continuous Markov process, using a chemical Langevin multiple slow reactions may occur within a time step of the numerical integration of the chemical Langevin

This data item presents the loss data for sudden contractions and expansions, orifice plates, valves (gate, globe, ball and diaphragm) and bends. In each case an equation is given for the two phase multiplier which, when it is applied as a factor to the single phase pressure loss calculated at the same mass flow rate, yields the two ...

The process of solidification of ternary systems in the presence of moving phase transition regions has been investigated theoretically in terms of the nonlinear equation of the liquidus surface. A mathematical model is developed and an approximate analytical solution to the Stefan problem is constructed for a linear temperature profile in two-phase zones. The temperature and ...

The process of solidification of ternary systems in the presence of moving phase transition regions has been investigated theoretically in terms of the nonlinear equation of the liquidus surface. A mathematical model is developed and an approximate analytical solution to the Stefan problem is constructed for a linear temperature profile in two-phase zones. The temperature and ...

In this paper we perform scoping calculations on the effects of two-phase zones on well pressure transients. Three different cases are considered. The first is that of a fully two-phase system (e.g. Krafla, Iceland). Some of the complexities of this type of system are discussed. The second problem is that of a single-phase liquid reservoir with a localized ...

The one-dimensional transient two phase flow in a geothermal well has been modeled with a finite difference approximation. The equations of mass, momentum and energy are solved using a partially implicit method. Terms that would place a severe time restriction on the calculation are solved implicitly while other terms are solved ...

Full-density Fe-Cu two-phase nanocomposites show microhardness considerably higher than the rule of mixtures (ROM) averages of constituent metals with the same nanophase grain size. This observation indicates that other than grain sizes and nominal phase volume fractions (used in ROM), microstructural arrangements of the two phases and ...

An accurate analytical approximation to the capacitance transient amplitude measured by deep level transient spectroscopy as a function of the filling pulse duration is derived. The equation includes the influence of a defect concentration profile and the nonexponential trapping in the Debye tail of the depletion region. Because this equation gives an ...

We derive a set of semianalytical solutions for the movement of solutes in immiscible two-phase flow. Our solutions are new in two ways: First, we fully account for the effects of capillary and viscous forces on the transport for arbitrary capillary-hydraulic properties. Second, we fully take hydrodynamic dispersion for the variable two-phase flow field ...