基于全欧拉方程的二维平行剪切层声波产生和辐射的数值模拟

本文基于全欧拉方程对二维平行剪切层声波的产生和辐射进行了计算气动声学数值模拟。空间离散采用了频散相关保持有限差分格式,时间积分采用了低频散低耗散的龙格库塔法。数值模拟结果表明,当声源强度较小时,基于全欧拉方程的计算结果与解析解及基于线化欧拉方程的计算结果均符合得很好,当声源强度较大时(约140dB),线化欧拉与全欧拉的计算结果有较大的偏差,这说明此时非线性的影响不可忽略,线化方程不再适用。 

Numerical Simulation of Sound Generation and Radiation from a 2-D Parallel Shear Layer Based on the Full Euler Equations

The generation and radiation of acoustic waves from a 2 D shear layer is numerically simulated by an aeroacoustic approach based on the 2 D full Euler equations.The dispersion relation-preserving (DRP) finite difference scheme is employed for space discretization and the low dissipation and low dispersion Runge Kutta (LDDRK) scheme is utilized for time integration.Numerical results show that the full Euler solutions agree well with the analytical solutions as well as the solutions by the linearized Euler equations if the amplitude of sound source is not too large.However,there is great discrepancy between the linear Euler and full Euler solutions if the strength of sound source is strong enough (140 dB).This means that the nonlinear effects can not be neglected whereas the linearized equations do not work.