Optimal research on volume velocity-matching wave superposition method based on tripole

Abstract

A volume velocity-matching wave superposition method for sound prediction of vibrating structure based on tripole is proposed. In the method, the position of the equivalent sources has similar geometry shape with radiating structure using a scale coefficient K. The calculating cut-off frequency of structure under a meshing pattern is predicted by setting 1.5% volume velocity relative error limit using surface vibration velocity. The cut-off frequency is defined as the maximum value of all wavenumber ka, at which the relative error just exceeds 1.5% when K iterates through (0,1) with step K. Then, for calculating frequency range [k1,k2], the optimal position of the equivalent sources, in which the relative error of volume velocity is minimum, is determined in the calculating cut-off frequency range by searching K in set {K|K,ka≥k2}. The transfer matrix between pressure and surface volume velocity is constructed in the optimal position by using tripole as equivalent source. After that, the sound radiation of structure is predicted to get high precision prediction. The results of numerical simulation show that the method is good at predicting the sound radiation of structure and the predicting error is very low within the cut-off frequency range once the optimal position is determined.