Boundary Element Analysis of Acoustic Radiation and Scattering in Half Space Using a Generalized Green’s Function

1992 ◽  
pp. 493-499
Author(s):  
W. L. Li ◽  
T. W. Wu ◽  
A. F. Seybert
Keyword(s):  
Green’S Function ◽  
Boundary Element ◽  
Half Space ◽  
Green's Function ◽  
Acoustic Radiation ◽  
Element Analysis ◽  
Boundary Element Analysis

Study on the Conditions of Near-Field Acoustic Levitation

2010 ◽  
Vol 97-101 ◽  
pp. 4135-4140 ◽  
Author(s):  
Yan De Liang ◽  
Hong Ling ◽  
Yuan Zhang
Keyword(s):  
Finite Element ◽  
Boundary Element ◽  
Radiation Pressure ◽  
Acoustic Radiation ◽  
Near Field ◽  
Acoustic Levitation ◽  
Element Analysis ◽  
Boundary Element Analysis ◽  
Acoustic Radiation Pressure

This paper establishes a near-field acoustic radiation pressure solving model applying with acoustics theory and derives an initial acoustic levitation calculating formula of rotundity objects. Combining with finite element and boundary element analysis, levitate conditions of levitated objects are calculated. This paper takes rectangular ultrasonic oscillator for example, testing and analyzing conditions of near-field acoustic levitation by using self-designed test equipments, the results are proved to be better.

Acoustical Green’s Function and Boundary Element Techniques for 3D Half-Space Problems

2017 ◽  
Vol 25 (04) ◽  
pp. 1730001 ◽  
Author(s):  
Rafael Piscoya ◽  
Martin Ochmann
Keyword(s):  
Green’S Function ◽  
Frequency Domain ◽  
Boundary Element ◽  
Half Space ◽  
Green's Function ◽  
Homogeneous Medium ◽  
Practical Implementation ◽  
Infinite Plane ◽  
Exterior Problems ◽  
Basic Concepts

This paper presents a review of basic concepts of the boundary element method (BEM) for solving 3D half-space problems in a homogeneous medium and in frequency domain. The usual BEM for exterior problems can be extended easily for half-space problems only if the infinite plane is either rigid or soft, since the necessary tailored Green’s function is available. The difficulties arise when the infinite plane has finite impedance. Numerous expressions for the Green’s function have been found which need to be computed numerically. The practical implementation of some of these formulas shows that their application depends on the type of impedance of the plane. In this work, several formulas in frequency domain are discussed. Some of them have been implemented in a BEM formulation and results of their application in specific numerical examples are summarized. As a complement, two formulas of the Green’s function in time domain are presented. These formulas have been computed numerically and after the application of the Fourier Transformation compared with the frequency domain formulas and with a FEM calculation.

A Parameter Study of the Burton–Miller Formulation in the BEM Analysis of Acoustic Resonances in Exterior Configurations

2020 ◽  
pp. 2050023
Author(s):  
Xin Chen ◽  
Qiang He ◽  
Chang-Jun Zheng ◽  
Cheng Wan ◽  
Chuan-Xing Bi ◽  
...  
Keyword(s):  
Boundary Element ◽  
Acoustic Radiation ◽  
Coupling Parameter ◽  
Acoustic Resonance ◽  
Integral Approach ◽  
Parameter Study ◽  
Scattering Problems ◽  
Element Analysis ◽  
Boundary Element Analysis ◽  
Acoustic Resonances

The application of a boundary element technique in combination with a contour integral approach to the numerical analysis of acoustic resonances in exterior configurations is investigated in this paper. Similar to the boundary element analysis of exterior acoustic radiation or scattering problems, spurious eigenfrequencies also turn up in the boundary element solution to exterior acoustic resonance problems. To filter out the spurious eigenfrequencies, the Burton–Miller-type combined formulation is employed to shift them from the real axis to the complex domain. The shifting effect brought by the combined formulation with different types of coupling parameters is investigated. Unlike in acoustic radiation and scattering analyses for which [Formula: see text] is suggested as the coupling parameter, it will be shown that the coupling parameter specified as [Formula: see text] with [Formula: see text] (the time-dependent term herein is [Formula: see text]) is more desirable in distinguishing the spurious eigenfrequencies in the boundary element analysis of exterior acoustic resonances.

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