{"title":"Deformable-boundary integral formulation for the solution of arbitrarily-forced acoustic wave equation","authors":"","doi":"10.1016/j.jsv.2024.118618","DOIUrl":null,"url":null,"abstract":"<div><p>The propagation of perturbations in fluids is governed by an acoustic wave equation. This paper, first, introduces an arbitrarily-forced wave equation which, properly adapted, gives rise to equations describing specific phenomena of signal perturbation propagation in fluids (like, for instance, the Lighthill and Ffowcs-Williams and Hawkings equations for radiation and scattering). Then, its solution is determined through a novel boundary integral formulation based on the free-space Green function, which is applicable to fluid domains bounded by solid or porous deformable surfaces. Different versions of the proposed boundary integral formulation can be derived, depending on the frame of reference in which they are expressed. The numerical investigation begins with the comparison of the results obtained by the presented formulation against analytical solutions concerning both a pulsating solid sphere and a deformable porous surface that encloses pulsating sources. Then, the equivalence of the formulations expressed in different frames is examined for a bending and twisting non-lifting wing translating at different Mach numbers. Finally, the aeroacoustic field generated by a helicopter rotor model in forward flight is examined to assess the effect of the body deformation on the radiated noise and the accuracy of the numerical simulations by comparison with experimental data. The results of the numerical investigation have provided a comprehensive validation of the deformable-boundary integral formulation presented for the analysis of wave propagation in fluids, and confirmed its capability to study problems of engineering interest.</p></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":4.3000,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0022460X24003808/pdfft?md5=dc2d329691f5f0e5375333bd77a750fc&pid=1-s2.0-S0022460X24003808-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Sound and Vibration","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022460X24003808","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ACOUSTICS","Score":null,"Total":0}
引用次数: 0
Abstract
The propagation of perturbations in fluids is governed by an acoustic wave equation. This paper, first, introduces an arbitrarily-forced wave equation which, properly adapted, gives rise to equations describing specific phenomena of signal perturbation propagation in fluids (like, for instance, the Lighthill and Ffowcs-Williams and Hawkings equations for radiation and scattering). Then, its solution is determined through a novel boundary integral formulation based on the free-space Green function, which is applicable to fluid domains bounded by solid or porous deformable surfaces. Different versions of the proposed boundary integral formulation can be derived, depending on the frame of reference in which they are expressed. The numerical investigation begins with the comparison of the results obtained by the presented formulation against analytical solutions concerning both a pulsating solid sphere and a deformable porous surface that encloses pulsating sources. Then, the equivalence of the formulations expressed in different frames is examined for a bending and twisting non-lifting wing translating at different Mach numbers. Finally, the aeroacoustic field generated by a helicopter rotor model in forward flight is examined to assess the effect of the body deformation on the radiated noise and the accuracy of the numerical simulations by comparison with experimental data. The results of the numerical investigation have provided a comprehensive validation of the deformable-boundary integral formulation presented for the analysis of wave propagation in fluids, and confirmed its capability to study problems of engineering interest.
期刊介绍:
The Journal of Sound and Vibration (JSV) is an independent journal devoted to the prompt publication of original papers, both theoretical and experimental, that provide new information on any aspect of sound or vibration. There is an emphasis on fundamental work that has potential for practical application.
JSV was founded and operates on the premise that the subject of sound and vibration requires a journal that publishes papers of a high technical standard across the various subdisciplines, thus facilitating awareness of techniques and discoveries in one area that may be applicable in others.