An isogeometric boundary element method for multi-frequency acoustic problems

Abstract：A multi-frequency calculation technique based on Taylor series expansion was introduced in the isogeometric boundary element method (IBIEM) for 3 D acoustic problems.The Taylor series expansion was used as the fitting function of the exponential term in fundamental solution, thus, all the entries in system matrices were independent of wave number.The entries in all the matrices (different wave number) only integrated once.Comparing with the original IBEM, the CPU time would be reduced much.A local B spline function was used in this geometric method, which could effectively avoid the singular points problems when mapping the parametric surface to the actual physical surface, and further improve the accuracy and efficiency of computation.At the same time, the geometric method made the mesh more convenient.The coupling isogeometric geometry method made the boundary element method realize the seamless connection between CAD and CAE.Numerical examples indicated the accuracy and efficiency of the presented technique.

Keyword：boundary element method;acoustic problem;Taylor series;multi-frequency calculation;