考虑地面影响的半空间气动噪声数值计算方法

含非紧致边界的半空间气动噪声问题普遍存在于航空领域，在数值计算过程中不仅要考虑非紧致边界的散射效应，还需要考虑地面对声波的反射。基于Lighthill声模拟理论和广义格林函数方法，引入边界声压积分项和可压缩修正项可以考虑非紧致边界以及流体可压缩性对声波散射的影响。然而在半空间声场的计算过程中，包含沿无限大地面的积分项，为了克服沿地面积分所带来的巨大工作量，根据无穷大平板对声波的反射特性，推导得出频域下基于半空间格林函数的声学积分方程。同时开展了半空间中应力源噪声与圆柱绕流噪声的数值预测与分析，验证了该方法的准确性与高效性。

A Numerical Method of Predicting the Aerodynamic Noise in a Half-space with Ground Effects

Aerodynamic noise in a half-space with non-compact boundaries widely exists in the area of aviation.When calculating noise problems numerically, the effects of the ground and other non-compact boundaries must be considered. Based on the Lighthill analogy and the generalized Green function method, the non-compact boundary effects and the fluid compressibility can be taken into consideration by bringing in the boundary sound pressure integral term and the compressible correction term. However, the integral along the infinite ground must be calculated when solving a half-space noise problem. In order to reduce the high computational expense, a new method using the half-space Green function is derived in the frequency domain based on the properties of sound reflection on a large flat. Meanwhile, through the numerical simulation of the stress noise and the flow-induced noise around a cylinder in a half-space, the accuracy and efficiency of the new method is validated.