Approximation to study the acoustic field diffracted in the shadow of a half‐infinite barrier by the boundary element method

1997 ◽  
Vol 102 (5) ◽  
pp. 3158-3158
Author(s):  
Antonio Sanchis ◽  
Albert Marín ◽  
José Romero ◽  
Alicia Giménez
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Field ◽  
Infinite Barrier ◽  
Element Method

Direct numerical simulation of three-dimensional dynamics of compressible bubbles in acoustic field using boundary element method

2014 ◽  
Vol 10 ◽  
pp. 59-65
Author(s):  
Yu.A. Itkulova ◽  
O.A. Abramova ◽  
N.A. Gumerov ◽  
I.Sh. Akhatov
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Field ◽  
Bubble Dynamics ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Numerical Approach ◽  
Low Reynolds Numbers ◽  
Dimensional Simulation ◽  
Element Method

In the present work the dynamics of bubbles containing compressible gas is studied in the presence of an acoustic field at low Reynolds numbers. The numerical approach is based on the boundary element method (BEM), which is effective for three-dimensional simulation. The application of the standard BEM to the compressible bubble dynamics faces the problem of the degeneracy of the algebraic system. To solve this problem, additional relationships based on the Lorentz reciprocity principle are used. Test calculations of the dynamics of one and several bubbles in an acoustic field are presented.

An Inverse Direct Time Domain Boundary Element Method for the Reconstruction of Transient Acoustic Field

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Yang Zhang ◽  
Xiao-Zheng Zhang ◽  
Chuan-Xing Bi ◽  
Yong-Bin Zhang
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Field ◽  
Time Domain ◽  
Domain Boundary ◽  
Hypersingular Integrals ◽  
Reconstruction Process ◽  
Linear System Of Equations ◽  
Value Decomposition ◽  
Element Method

An inverse direct time domain boundary element method (IDTBEM) is proposed for the reconstruction of transient acoustic field radiated by arbitrarily shaped sources. The method is based on the theory of direct time domain boundary element method (DTBEM), which is free from the calculation of hypersingular integrals, and thus, its reconstruction process is relatively simple and easy to implement. However, the formulations of DTBEM cannot be used directly for the reconstruction of transient acoustic field, and therefore, new formulations with a modified time axis are derived. With these new formulations, a linear system of equations is formed and the reconstruction is performed in a marching-on-time (MOT) way. Meanwhile, to deal with the ill-posedness involved in the inverse process, the truncated singular value decomposition (TSVD) is employed. Numerical simulations with three examples of a sphere, a cylinder, and a simplified car model are carried out to verify the validity of IDTBEM, and the results demonstrate that the IDTBEM is effective in reconstructing the transient acoustic fields radiated by arbitrarily shaped sources in both time and space domains.

Acoustic characteristic analysis of power transformers in urban communities based on a combined finite and boundary element method

2019 ◽  
Vol 29 (2) ◽  
pp. 208-220
Author(s):  
Liming Ying ◽  
Donghui Wang ◽  
Guodong Wang ◽  
Wenyi Wang
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Field ◽  
Sound Pressure ◽  
Power Transformer ◽  
Power Transformers ◽  
Spatial Sound ◽  
Sound Pressure Levels ◽  
External Acoustic Field ◽  
Element Method

Power transformers in substations are common sources of noise in residential areas of neighbourhoods. A quantified and visualized analysis of the power transformer acoustic characteristics is a prerequisite for the suppression of audible noise from the corresponding substation. In this study, based on a combined finite and boundary element method, a full-sized 3D power transformer multiphysics coupling model, which is aimed at realizing high accuracy and improving the computational efficiency, was developed. After validation of the numerical method using comparative tests, profile analyses in the near-field and far-field in the extended planes and three-dimensional areas of a power transformer were conducted to characterize the external acoustic field. The calculation results included the distribution of the spatial sound pressure levels of the power transformer at multiple levels in the frequency domain. These spatial sound pressure levels can be used to guide the efficient measurement of the external acoustic field of a power transformer and the soundscape planning around a substation, and the differentiated design of the sound absorption structure inside a substation.

An Indirect Boundary Element Method for Computing Sound Field

2012 ◽  
Vol 476-478 ◽  
pp. 1173-1177
Author(s):  
Sheng Yao Gao ◽  
De Shi Wang
Keyword(s):  
Integral Equation ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Field ◽  
Boundary Surface ◽  
Sound Field ◽  
Boundary Integral ◽  
Superposition Method ◽  
Wave Superposition ◽  
Element Method

Computing sound field from an arbitrary radiator is of interest in acoustics, with many significant applications, one that includes the design of classical projectors and the noise prediction of underwater vehicle. To overcome the non-uniqueness of solution at eigenfrequencies in the boundary integral equation method for structural acoustic radiation, wave superposition method is introduced to study the acoustics. In this paper, the theoretical backgrounds to the direct boundary element method and the wave superposition method are presented. The wave superposition method does not solve the Kirchoff-Helmholtz integral equation directly. In the approach a lumped parameter model is estabiled from spatially averaged quantities, and the numerical method is implemented by using the acoustic field from a series of virtual sources which are collocated near the boundary surface to replace the acoustic field of the radiator. Then the sound field over the of a pulsating sphere is calculated. Finally, comparison between the analytical and numerical results is given, and the speed of solution is investigated. The results show that the agreement between the results from the above numerical methods is excellent. The wave superposition method requires fewer elements and hence is faster, which do not need as high a mesh density as traditionally associated with BEM.

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