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为避免气动噪声数值模拟中流场高精度计算所带来的巨大工作量,同时考察非紧致边界的散射效应,采用二阶精度格式进行可压缩流场计算,将流场脉动量分解为流场数值计算捕获的主要由流体运动引起的流动脉动分量和流场计算未捕获的主要由噪声传播引起的声学脉动分量两部分,基于Lighthill声模拟理论和格林函数波动方程,导出气动噪声辐射散射统一积分计算方法。首先将观察点布置在物体表面,通过统一积分方程计算得到非紧致物面边界上的散射声压,然后将观测点移到远场位置计算得到声场区域内任意观察点的声压。对二维、三维圆柱以及二维翼型开展气动噪声数值计算,结果与文献计算以及实验结果相吻合,表明本文提出的这种统一积分计算方法能够减少流场高精度计算所需的工作量,同时还能够准确地模拟非紧致结构对气动噪声的散射效应。
In order to avoid the huge workload caused by the high precision calculation of the flow field in the numerical simulation of aerodynamic noise and to investigate the scattering effects on the noncompact boundary, the second-order accuracy format is used to calculate the compressible flow field, In the field numerical calculation, the fluctuating component of the fluid that is mainly caused by the fluid motion and the unacquired acoustic component of the noise mainly caused by the noise propagation are calculated. Based on the Lighthill acoustic simulation theory and the wave equation of Green’s function, Integral calculation method. First, the observation point is arranged on the surface of the object, and the scattered sound pressure on the boundary of the non-compact object is calculated by the unified integral equation. Then the observation point is moved to the far field to calculate the sound pressure at any observation point in the sound field area. The aerodynamic noise of two-dimensional, three-dimensional cylinders and two-dimensional airfoils are numerically calculated. The results are in good agreement with the literature and experimental results. The results show that the proposed method can reduce the workload of high- At the same time, it can accurately simulate the scattering effect of non-compact structure on aerodynamic noise.