Aeroacoustic prediction for cooling fan using convolution quadrature boundary element method

J Acoust Soc Am. 2021 Sep;150(3):1912. doi: 10.1121/10.0006111.

Abstract

A computational method to predict the aeroacoustic sound produced by the interaction between fluid and moving body is developed, then applied to the problem of aerodynamic noise radiation from an engine cooling fan. The flow field is computed using the viscous vortex method with a simplified diffusion algorithm, followed by a noise sources extraction within the turbulent region, based on the vortex sound model. Then, the sound field is determined using a Convolution Quadrature Boundary Element Method, accounting for the scattering effect from solid surface. With the help of Convolution Quadrature Method, time-stepping Boundary Element procedure can be established circumventing the requisite for time-dependent fundamental solution. Fast Multipole Method is also adopted to improve computational efficiency. It is found that the results of flow field calculation are close to those obtained from measurement. The predicted noise levels at the microphone position are in qualitative agreement with the measured. The comparison of computation time also shows that the proposed method can effectively predict the fluid-blade interaction noise.