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3 edition of Fundamental investigations of the finite element solutions for acoustic propagation in ducts found in the catalog.

Fundamental investigations of the finite element solutions for acoustic propagation in ducts

Fundamental investigations of the finite element solutions for acoustic propagation in ducts

final report

  • 128 Want to read
  • 29 Currently reading

Published by National Aeronautics and Space Administration in [Washington, DC .
Written in English

    Subjects:
  • Acoustical engineering.

  • Edition Notes

    StatementN.J. Walkington, T.M. Wicks, and W. Eversman.
    SeriesNASA-CR -- 179845., NASA contractor report -- NASA CR-179845.
    ContributionsWicks, T. M., Eversman, Walter., United States. National Aeronautics and Space Administration.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15278364M

    An analysis of the acoustic energy flux is performed, revealing that local differences in fluctuating stagnation enthalpy, distributed over a finite length of duct, are responsible for absorption, and that both liners in a double-liner system are absorbant. Acoustics and Vibration The mathematical foundations were laid for acoustics and vibration analysis by Lord Rayleigh in his book The Theory of Sound, which was first published in From the transducer point of view, notable contributions were made by the Curie brothers, who discovered piezoelectricity in , and by some of the great theoreticians such as A.E.H. Love, who made important.

    () did a comparison of this method with the acoustic analogy. Both methods gave solutions that agree with the experimental data. This approach is limited to flows where the viscosity is not important; it encounters fundamental difficulties when the Reynolds number is high due to . Full text of "NASA Technical Reports Server (NTRS) Aeronautical Engineering: A continuing bibliography, cumulative index" See other formats.

    PROCEEDINGS VOLUME Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security Crack propagation testing using a YCOB acoustic emission sensor Utilizing a general purpose finite element approach for assessing the rotordynamic response of a flexible disk/shaft system. Proc. SPIE , Health Monitoring of Structural and Biological Systems , (9 May ); doi: /


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Fundamental investigations of the finite element solutions for acoustic propagation in ducts Download PDF EPUB FB2

Get this from a library. Fundamental investigations of the finite element solutions for acoustic propagation in ducts: final report. [N J Walkington; T M Wicks; Walter Eversman; United States. National Aeronautics and Space Administration.].

Acoustic wave propagation in flow ducts is commonly modeled with time-domain non-linear Navier-Stokes equation methodologies. To reduce computational effort, investigations of a linearized. Experimental investigations and numerical simulations of normal shock waves of different strengths propagating inside ducts with roughness are presented.

The roughness is added in the form of grooves. B.J. TESTER Jottrnal of Sound attd Vibrat Ray models for sound propagation and attenuation in ducts, in the absence of mean flow.

TESTER Journal of Sound and Vibrat Acoustic energy flow in lined ducts containing uniform or "plug" flow. B.J. TESTER Journal of Sound and Vibration 28 Cited by: A specialized finite element program is used to predict the propagation behavior of asymmetrically bifurcated cracks, which can cause crack growth retardation and arrest.

The branched crack propagation path and associated stress intensity factors (SIF) are obtained for several bifurcation angles. () A depth-integrated non-hydrostatic finite element model for wave propagation. International Journal for Numerical Methods in Fluids() Enhancement of convective heat transfer by electrically-induced swirling effect in laminar and fully-developed internal by: APPLIED FINITE ELEMENT, FINITE DIFFERENCE, AND BOUNDARY ELEMENT METHODS (3) Applications of numerical methods in the areas of structures, fluid dynamics, heat and mass transfer, machine design.

THERMAL PHENOMENA IN FOOD ENGINEERING (3) Heat and mass transfer phenomena, nutrient degradation rates, and energy use in food processing.

Thus, the prediction of noise level may lead to significant design problem. In this paper, we developed prediction method for the noise reduction level of main casing. The main casing consists of finned tube bank which is considered as a silencer.

The FEA (Finite Element Acoustic) is applied to noise attenuation process of tube bundle. () A depth-integrated non-hydrostatic finite element model for wave propagation. International Journal for Numerical Methods in Fluids() Numerical simulation of turbulent reacting flow in porous media using two macroscopic turbulence by: The finite element model was derived from the resulting volumetric image by converting each voxel corresponding to dense bone into a finite element.

A moderate amount of Laplacian smoothing was applied both on the surface and in the interior to enhance the smoothness of the boundary by: This banner text can have markup.

web; books; video; audio; software; images; Toggle navigation. Three-deminsional finite-element analysis of finite-thickness fracture specimens / (Washington: National Aeronautics and Space Administration ; Springfield, Va.: For sale by the National Technical Information Service, ), by I.

Raju, J. Newman, Langley Research Center, and United States National Aeronautics and Space Administration. Finite element solution of the helmholtz equation with high wave number part ii: The h-p version of the fem.

SIAM J. Numer. Anal., 34(1){ [52]Kechroud, R., Antoine, X., and Soula mani, A. Numerical accuracy of a Pad e-type non-re ecting boundary condition for the nite element solution of acoustic scattering problems at high Cited by: 2.

The experimental results are compared with finite-element computations. Acoustic emission is based on the detection/analysis of the sonic energy emitted by a material under stress.

It is a passive condition monitoring that allows continuous testing of a structure while in service rather than at regular by: Book Description: The growth of aviation and the increasing size and power of aircraft has made aerodynamic noise a major problem.

Control of this noise will only be possible when more is known of its generation, propagation, and attenuation. Global concern over the possible deleterious effects of noise on marine organisms was catalyzed when toothed whales stranded and died in the presence of high intensity sound.

The lack of knowledge about mechanisms of hearing in toothed whales prompted our group to study the anatomy and build a finite element model to simulate sound reception in odontocetes.

No Access A comparison of DMSP and NTS-2 dosimeter measurements with predictions, using the NASA models AEI-7 HI and AP-8magnetically trapped proton and outer zone electron models for energetic particle effects on earth satellites.

flexural vibration band gaps in advanced composite grid structures using finite element method. wang, j. / wang, g a meshless model for 3d sound propagation through acoustic attenuators and expansion chambers. identification of acoustic boundary characteristics of an enclosed sound field using the fundamental solutions.

kamiya, k. Although this book is intended primarily for undergraduate students, it is also suitable for the early part of finite element courses in postgraduate programme. The basic and conceptual approaches which are used also make this book appropriate for practising engineers who want to.

Astley R. J.,A finite element scheme for acoustic propagation in flexible-walled ducts with bulk-reacting liners, and comparison with experiment, Journal of Sound and Vibration, (1), 6. Fundamental chapters on the physics and perception of sound precede those on noise reduction methods.

A chapter dealing with microphines, loudspeakers, and acoustical antennae is included as well as a chapter on the fundamentals of signal and system theory. Practice exercises with solutions serve for the application of the entire content.The book also establishes an intelligent balance among the essentials of EM MODSIM: The Problem (the physics), The Theory and Models (mathematical background and analytical solutions), and The Simulations (code developing plus validation, verification, and calibration).

PROCEEDINGS VOLUME Studying the effect of cracks on the ultrasonic wave propagation in a two dimensional gearbox finite element model. Utilizing a general purpose finite element approach for assessing the rotordynamic response of a flexible disk/shaft system.