Convolution Quadrature Time-Domain Boundary Element Method for Two-Dimensional Aeroacoustic Noise Prediction

Abstract

The computation of a compressible flow for aeroacoustic prediction is a challengeable work insofar as the fluctuation is usually very small in a sound field compared with the flow field. For the low Mach number considered in this study, a discrete vortex method in conjunction with fast multipole time-domain boundary element method is developed and applied to predict far-field sound resulting from a 2D vortex dominated flow. The flow field is simulated employing the classical discrete vortex method. The sound field scattered by solid bodies is determined by using a time-domain boundary element method combined with the convolution quadrature approach, by means of which the convolution integral is approximated by a quadrature formula utilizing a Laplace-domain fundamental solution. In addition, the fast multipole method is applied to improve the computational efficiency. Finally, several examples are presented to check the applicability and accuracy of the method. Numerical results indicate that the noise predicted by the present method agrees well with the experimental results, and the sound pressure levels of the cylinder models have a dipole-like directivity at vortex shedding frequency.