An efficient technique for multi-frequency acoustic analysis by boundary element method

Abstract

A new technique for multi-frequency acoustic analysis by boundary element method is proposed. This new technique is based on the elimination of the frequency-dependent character of the boundary element coefficient matrices. By making use of the algebraic polynomials and taking out the frequency term from integrands, numerical integration involved in setting up the coefficient matrices is only confined to a frequency-independent part and the boundary element global coefficient matrices obtained by this technique are frequency independent. The final global coefficient matrices at any frequency can be simply formed by a summation of the frequency-independent global matrices and the need to compute the numerical integration at each frequency is eliminated. The technique therefore seems to be especially interesting when the bulk of the computational effort is spent on the integration phase of the solution process for a multi-frequency analysis. The test case of sound radiation from a pulsating sphere is given to demonstrate the technique. The numerical results show that this new technique can significantly save the CPU time for a multi-frequency problem.