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Titolo:
Modal acoustic force on a spherical radiator in an acoustic halfspace withlocally reacting boundary
Autore:
Hasheminejad, SM;
Indirizzi:
Iran Univ Sci & Technol, Dept Mech Engn, Tehran 16844, Iran Iran Univ Sci & Technol Tehran Iran 16844 Mech Engn, Tehran 16844, Iran
Titolo Testata:
ACUSTICA
fascicolo: 4, volume: 87, anno: 2001,
pagine: 443 - 453
SICI:
1436-7947(200107/08)87:4<443:MAFOAS>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
ELASTIC POROUS MATERIALS; SOUND-PROPAGATION; EMPIRICAL-MODEL; POINT-SOURCE; DYNAMIC PERMEABILITY; COMPRESSIONAL WAVE; IMPEDANCE PLANE; MEDIA; SURFACE; FLUID;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Engineering, Computing & Technology
Citazioni:
53
Recensione:
Indirizzi per estratti:
Indirizzo: Hasheminejad, SM Iran Univ Sci & Technol, Dept Mech Engn, Tehran 16844, Iran Iran Univ Sci & Technol Tehran Iran 16844 n 16844, Iran
Citazione:
S.M. Hasheminejad, "Modal acoustic force on a spherical radiator in an acoustic halfspace withlocally reacting boundary", ACUSTICA, 87(4), 2001, pp. 443-453

Abstract

The modal acoustic load on a spherical surface undergoing angularly periodic axisymmetric harmonic vibrations while immersed in an acoustic halfspacewith a locally reacting (finite impedance) planar boundary is analyzed in an exact fashion using the classical technique of separation of variables. The solution of the problem is generated by systematically analyzing multi-scattering interaction between the spherical source and the impedance boundary that can be strong or weak depending on their separation, local surfacereaction, and frequency. The formulation utilizes the appropriate wave field expansions and a simple local surface reaction framework along with an approximate acoustical wave propagation model involving a complex amplitude spherical wave reflection coefficient which are sensibly applied to simulate the relevant boundary conditions for the given configuration. Incorporation of the the classical method of images and the appropriate translational addition theorem permit us to express the acoustic field variables as pairsof double summations in the spherical wave functions, with the coefficients that are coupled through an infinite set of linear complex algebraic equations. These are then truncated and further manipulated to yield the modal impedance matrix and subsequently the modal acoustic force acting on the spherical surface is determined. The analytical results are illustrated with a numerical example in which the spherical surface, excited in vibrational modes of various orders, is immersed near a layer of (locally reacting) fibrous material set on an impervious rigid wall. The obtained data agree wellwith the approximations given by Morse and Ingard [1] for mechanical impedance of monopole and dipole sources located not very close to the finite impedance plane. The present benchmark solution could eventually be used to validate those found by numerical approximation techniques.

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Documento generato il 05/04/20 alle ore 03:31:58