基于Khokhlov-Zabolotskaya-Kuznetsov方程的声爆频域预测法

建立了一种快速预测声爆传播特性的频域方法,基于传统Khokhlov-Zabolotskaya-Kuznetsov(KZK)方程,描述声爆沿激波波阵面法线方向的传播.为了验证模型正确性,以NASA TD N-161中试件C为对象,首先基于不同网格,利用计算流体动力学(CFD)方法得到超声速流场;将CFD结果作傅里叶变换后代入模型方程,快速求解声爆传播特性.预测结果与NASA实验结果符合很好,研究表明:预测方法能够捕捉声爆的非线性传播,声衍射项使得声场在远场趋于轴对称分布,远距离传播后声能量集中于低频分量.

Frequency domain method for predicting sonic boom propagation based on Khokhlov-Zabolotskaya-Kuznetsov equation

A fast frequency domain method for predicting sonic boom propagation was proposed based on classical Khokhlov-Zabolotskaya-Kuznetsov(KZK) equation.Furthermore,the sonic boom properties along the normal direction to the shock front were obtained by augmenting the Mach angle into the equation.To demonstrate the feasibility of the method,the results were compared with the experimental data of the model C presented in NASA TD N-161.The flow field of the supersonic moving vehicle was first calculated by a computational fluid dynamics(CFD) method with different grids.Then,the sonic boom propagation was computed based on the proposed KZK model with the input of the Fourier analysis results from CFD.The prediction results are in good agreement with NASA experimental data.It is also shown that the sonic boom decays rapidly in the near field due to the nonlinearity effects.In the far field,the sonic boom becomes axisymmetric gradually due to the effect of sound diffraction.After long distance propagation,the sound energy is concentrated on low frequency component.