A computational acoustic field reconstruction process based on an indirect variational boundary element formulation

Abstract

The objective of this work is to develop a computational capability based on the indirect variational boundary element method (IVBEM) to evaluate appropriate velocity boundary conditions on an assembly of piston-type sources such that they can recreate a prescribed acoustic field. Information for the acoustic pressure of the original acoustic field at certain field points constitutes the input to the developed process. Several new developments associated with the IVBEM are necessary for completing the field reconstruction process. The developed computational capability targets exterior radiation applications. Thus a new formulation for treating irregular frequencies in the IVBEM is developed and implemented in the field reconstruction process. The computation of the appropriate velocities for the piston-type sources is based on deriving transfer functions between the field points, where the acoustic pressure of the original field is prescribed, and the velocity assigned on each element of the generic source. A singular value decomposition solver is integrated with the IVBEM computations in order to evaluate the velocity boundary conditions from the transfer functions. Finally, an algorithm that identifies the optimum field points from a set of candidate points for prescribing the acoustic pressure of the original field is developed. [Research supported by a University Research Program award from Ford Motor Co.]