A fast and efficient algorithm for acoustic resonances of a 3D open cavity with asymmetrical walls

Abstract

Cavities with asymmetrical walls exist in many industrial applications and its acoustic properties are crucial to noise and vibration control. However, traditional methods are complex and time-consuming such as finite element method (FEM). Given the problems existing in traditional methods, the ISM-TM algorithm which combined the image source model (ISM) with the transformation matrix (TM) is proposed to explore acoustic resonances of a 3D open cavity with asymmetrical walls in this work. Compared with experiments, the proposed algorithm can well obtain the acoustic resonances of a 3D open rectangle cavity and a 3D open cavity with non-parallel walls. In a 3D open rectangle cavity, with the increase of the calculation frequency, the relative error between acoustic resonant frequencies measured by experiments and estimated by the ISM-TM is reduced from 11.3% to 0.9%. In a 3D open cavity with non-parallel walls, with the increase of the calculation frequency, the relative error between acoustic resonant frequencies measured by experiments and estimated by the ISM-TM is reduced from 2.3% to 0.2%. The results suggest that the proposed algorithm in this work could well estimate acoustic resonances of a 3D open cavity for medium and high frequency. Compared with the FEM, the proposed algorithm can provide the frequency response function (FRF) of any point in a 3D open cavity easily and quickly. The ISM-TM can be used to guide cavity design to predict possible acoustic resonances in the cavity in advance.