scholarly journals A simplified two-dimensional boundary element method with arbitrary uniform mean flow

2017 ◽  
Vol 7 (4) ◽  
pp. 207-221 ◽  
Author(s):  
Bassem Barhoumi ◽  
Safa Ben Hamouda ◽  
Jamel Bessrour
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Two Dimensional ◽  
Mean Flow ◽  
Dimensional Boundary ◽  
Element Method

scholarly journals Predicted Absorption Performance of Cylindrical and Rectangular Permeable Membrane Space Sound Absorbers Using the Three-Dimensional Boundary Element Method

2019 ◽  
Vol 11 (9) ◽  
pp. 2714 ◽  
Author(s):  
Masahiro Toyoda ◽  
Kota Funahashi ◽  
Takeshi Okuzono ◽  
Kimihiro Sakagami
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Dimensional Analysis ◽  
Prediction Accuracy ◽  
Sound Absorption ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Permeable Membrane ◽  
Dimensional Boundary ◽  
Element Method

Three-dimensional, permeable membrane space sound absorbers have been proposed as practical and economical alternatives to three-dimensional, microperforated panel space sound absorbers. Previously, the sound absorption characteristics of a three-dimensional, permeable membrane space sound absorber were predicted using the two-dimensional boundary element method, but the prediction accuracy was impractical. Herein, a more accurate prediction method is proposed using the three-dimensional boundary element method. In the three-dimensional analysis, incident waves from the elevation angle direction and reflected waves from the floor are considered, using the mirror image. In addition, the dissipated energy ratio is calculated based on the sound absorption of a surface with a unit sound absorption power. To validate the three-dimensional numerical method, and to estimate the improvement in prediction accuracy, the results are compared with those of the measurements and two-dimensional analysis. For cylindrical and rectangular space sound absorbers, three-dimensional analysis provides a significantly improved prediction accuracy for any shape and membrane sample that is suitable for practical use.

Application of the Boundary Element Method to Predict the Acoustic Field in a Two-Dimensional Duct

1991 ◽  
Author(s):  
Carl S. Pates ◽  
Uday S. Shirahatti
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Accurate Method ◽  
Classical Solutions ◽  
Element Formulation ◽  
Two Dimensional ◽  
Mean Flow ◽  
Flight Vehicles ◽  
Acoustic Problem ◽  
Element Method

Abstract In the development of the newer supersonic and hypersonic flight vehicles, an increased need for the analysis of acoustic fields and the response of structures to acoustic loads in the presence of high temperature and large mean flow velocities have become necessary. A major concern has been in the area of pressure fields associated with ducts. Such acoustic ducts are frequently used to test the response of various structural elements of flight vehicles. Many new methods have been created and used to approximate the sound fields in ducts. Since the region or boundary of an acoustic problem can extend to infinity, some approximating methods require much time and effort to solve the problem. Many ways have been examined to simplify the acoustic problem and still obtain reasonable results. In the past thirty years, the boundary element method (BEM) has been researched and proven to be an extremely simplified and accurate method for solving acoustic problems. Since BEM only discretizes the boundary, the dimensionality of the problem is reduced by one. This paper presents a boundary element formulation to predict the pressure field in a two-dimensional acoustic duct. The boundary conditions basically consist of two types: known pressure or known normal derivative of pressure. In order to examine the boundary element method, a 2-D rectangular duct problem will be investigated. The example problem will consist of a duct with rigid walls and a specified pressure distribution at the entrance. Pressure values will be calculated for boundary nodes using the boundary element method. These values will be compared with the available classical solutions.

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