Numerical study of wave propagation in a non-uniform flow



Publisher: ICASE, NASA Langley Research Center, Publisher: Available from NASA Center for Aerospace Information in Hampton, VA, Hanover, MD

Written in English
Published: Downloads: 812
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Subjects:

  • Aeroacoustics.,
  • Sound waves.,
  • Sound propagation.,
  • Wave propagation.,
  • Nonuniform flow.,
  • Stagnation flow.,
  • Acoustic emisson.,
  • Numerical analysis.,
  • Integral equations.

Edition Notes

StatementAlex Povitsky.
SeriesICASE report -- no. 2000-35., [NASA contractor report] -- NASA/CR-2000-210533., NASA contractor report -- NASA CR-210533.
ContributionsInstitute for Computer Applications in Science and Engineering.
The Physical Object
FormatMicroform
Pagination1 v.
ID Numbers
Open LibraryOL16030539M

A numerical study of wave propagation in a confined mixing layer by eigenfunction expansions. Physics of Fluids A: Fluid Dynamics (), 5 (6), pp. – Hu, F. Q., Jackson, T., Lasseigne, D., and Grosch, C. E. (). Absolute–convective instabilities and their associated wave packets in a compressible reacting mixing layer. Numerical study of the flow and passive scalar transport in an open-channel confluence with a flat and a degraded fixed bed, Numerical simulation of non-uniform bed-load transport using a Lagrangian method and probabilistic Exner equation, Wave propagation in porous structures based on ISPH method, M. Ramos-Ortega. It is shown by using a Dispersion-Relation-Preserving finite difference scheme that it is feasible to perform direct numerical simulation of acoustic wave propagation problems. The finite difference equations of the scheme have essentially the same Fourier-Laplace transforms and hence dispersion relations as the original linearized Euler equations over a broad range of wavenumbers (here. One of the reasons for this is that when a seismic wave propagates through fluid‐saturated formations containing heterogeneities in the mesoscopic scale range, that is, at scales smaller than the prevailing wavelengths but larger than the typical grain size, it experiences significant attenuation and phase velocity dispersion due to a.

  This paper presents a numerical study of the dynamic compaction (DC) process, based on the finite element method, with the main attention on the role of water content on the soil response. Dynamic compaction is one of the most cost-effective techniques available for soil improvement, where the soil is compacted by repeatedly dropping free. The effect of the duct wall roughness on the shock wave attenuation is also studied. The main flow diagnostic used in the experimental part is either an interferometric study or alternating shadow–schlieren diagnostics. The photos obtained provide a detailed description of the flow evolution inside the ducts investigated. The principal application targeted is wave propagation in aeroacoustics in collaboration with Airbus SAS, where the source of inhomogeneity is the non-uniform flow, but the methods considered in this project will also apply to other variable material properties such as permittivity or sound speed. MIT's Department of Mechanical Engineering (MechE) offers a world-class education that combines thorough analysis with hands-on discovery. One of the original six courses offered when MIT was founded in , MechE's faculty and students conduct research that pushes boundaries and provides creative solutions for the world's problems.

  A nonstandard wave equation, established by Galbrun in , is used to study sound propagation in nonuniform flows. Galbrun’s equation describes exactly the same physical phenomenon as the linearized Euler’s equations (LEE) but is derived from an Eulerian–Lagrangian description and written only in term of the Lagrangian perturbation of the displacement. Vladimir Prokofev, Multilayer open flow model: A simple pressure correction method for wave problems, International Journal for Numerical Methods in Fluids, /fld, 86, 8, (), (). Simulation Study on the Process of Pressure Wave Propagation for High-Pressure Common Rail Diesel Engine In this paper, pressure fluctuation in a high-pressure common rail system has been investigated through numerical simulation method. By establishing a three-dimensional (3D) model and one-dimensional (1D) simulation model of a. In this study, the NEWTANK (numerical wave tank) model [9, 10], which is a well-validated numerical model using a large eddy simulation, is employed to predict runup heights of nonlinear waves that passed a submerged structure in the surf zone. Reduced runup heights are predicted and their characteristics in terms of wave reflection.

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Numerical Study of Wave Propagation in a Non-uniform Flow Alex Povitsky ICASE, Hampton, Virginia Institute for Computer Applications in Science and Engineering NASA Langley Research Center Hampton, VA Operated by Universities Space Research Association September Prepared for Langley Research Center under Contract NAS The propagation of acoustic waves originating from cylindrical and spherical pulses in a nonuniform mean flow, and in the presence of a reflecting wall, is investigated by solving linearized Euler equations in terms of disturbances using high-order compact approximation of spatial derivatives.

The two-dimensional and three-dimensional stagnation flows and a flow around a cylinder are taken as Cited by: PDF | The propagation of acoustic waves originating from cylindrical and spherical pulses in a nonuniform mean flow, and in the presence of a reflecting | Find, read and cite all the research Author: Alex Povitsky.

Get this from a library. Numerical study of wave propagation in a non-uniform flow. [Alex Povitsky; Institute for Computer Applications in Science and Engineering.]. Numerical study of wave propagation in a nonuniform compressible flow Alex Povitsky a) Department of Mechanical and Industrial Engineering, Concordia University, Montreal, Quebec.

CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): The propagation of acoustic waves originating from cylindrical and spherical pulses, in a non-uniform mean flow, and in the presence of a reflecting wall is investigated by Hardin and Pope approach using compact approximation of spatial derivatives.

The 2-D and 3-D stagnation ows and a flow around a cylinder are taken. NUMERICAL STUDY OF WAVE PROPAGATION IN A NON-UNIFORM FLOW. By Alex Povitsky. Abstract. The propagation of acoustic waves originating from cylindrical and spherical pulses, in a non-uniform mean flow, and in the presence of a reflecting wall is investigated by Hardin and Pope approach using compact approximation of spatial derivatives.

The 2-D. A numerical method for free-surface flow is presented to study water waves in coastal areas. The method builds on the nonlinear shallow water equations and utilizes a non-hydrostatic pressure term to describe short waves.

A vertical boundary-fitted grid is used Numerical study of wave propagation in a non-uniform flow book the water depth divided into a.

propagation of any potential detonation wave in this non-uniform mixture despite their relevance to safety concerns. Detonation propagation in a semi-confined flat layer filled with non-uniform hydrogen-air mixture with varying initial hydrogen pressures has.

The book presents the latest advances in numerical simulations of optical wave propagations in turbulent media.

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This book will benefit optical scientists and engineers at all. In the present work we use a modified version of the weakly-compressible SPH scheme with diffusive terms described in Antuono et al.

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This study investigates the effects of porosity variation on self-propagating high-temperature synthesis of Ti + 2B using numerical simulations. This study has shown that porosity variation influences the thermophysical/chemical parameters, such as thermal conductivity and density, and further changes the propagation manners of a combustion front.

Experimental and numerical study of shock wave propagation over cylinders and spheres A. Abe', K. Takayama', K. Itoh* * Shock Wave Research Center of Institute of Fluid Science, Tohoku University, Japan Kakuda Research Center, National Aerospace Laboratory, Japan Abstract This is a preliminary study of shock wave attenuation over arrays of.

Based on the numerical model, EOS, and the failure criterion, the influences of these factors on crack initiation and propagation will be investigated in the follows. Conclusions. This study emphasizes the role of stress wave loading on crack initiation and propagation during the initial stage of.

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The results of direct numerical simulations of the flow generated in a plane duct by a pressure gradient which is the sum of two terms are described. The first term of the pressure gradient is constant in space but it oscillates in time whereas the second term is constant both in space and in time.

Therefore, a pulsating flow is generated, similar to that generated at the bottom of a. 5) Sound propagation was affected by non-uniform flow to a large extent. When the noise problem caused by turbulent flow was numerically studied, therefore, the impact of such non-uniform shear flow should be taken seriously so as to obtain correct results.

Due immediately behind the barrier, where the flow is highly unsteady and nonuniform in the other, placed further downstream from the barrier, the flow approaches a steady and uniform state.

It is also shown that most of the attenuation experienced by the transmitted shock wave occurs in the zone where the flow is highly unsteady. A two-dimensional numerical model is developed to study the propagation of a solitary wave in the presence of a steady current flow.

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