关于气动声学数值计算的方法与进展

Numerical Methods and Advances for Aeroacoustics

气动声学数值计算是近年才出现的研究领域。本文介绍了气动声学数值计算的方法和有关的问题、边界条件的处理以及计算非线性声波的数值方法和进展。讨论了计算气动声学(CAA)的特性及其与计算流体力学(CFD)的差异,指出气动声学数值方法的关键是建立能保持色散关系的差分方程和正确处理无反射边界条件。对于非线性声波传播的问题,为了得到正确的解,应注意提高差分格式对短波的分辨能力,同时发展能抑制“伪”振荡(短波)而对长波基本不起作用的数值方法。

The relatively new field of computational aeroacoustics(CAA) has emerged in recent years. In this paper, the numerical methods, issues and development for aeroacoustics, were described, including finite difference scheme, boundary conditions and nonlinear acoustics and shocks. The characteristics of CAA and the difference between CAA and CFD-Computational Fluid Dynamics CFD were discussed. It is pointed out that the dispersion-relation-preserving finite difference schemes and appropriate nonreflecting boundary conditions are of critical importance to numerical methods for aeroacoustics. For the problem of nonlinear acoustics, the resolution of high-order differencing must be improved. In order to get exact numerical solution, some numerical procedure should be developed to eliminate oscillations with short wavelength, but the components of longer wavelengths are virtually unaffected.