高超声速内外流一体化飞行器动态特性

Dynamic Characteristics of Hypersonic Integrative Vehicle With Internal and External Flow

基于三维非定常N-S方程,数值研究了吸气式高超声速机体/推进一体化飞行器的动态特性。空间方向的离散采用二阶精度的Roe格式,非定常流动求解采用"双时间步"方法的隐式LU-SGS格式。基于Etkin非定常气动力模型,采用小振幅强迫简谐分析法发展了动态阻尼导数的数值计算方法。在Finner标模验证的基础上,针对高超声速内外流一体化飞行器开展动导数辨识。对时间步长、子迭代步数、减缩频率等参数的影响进行了计算分析,结果表明:减小时间步长、加大子迭代步骤可提高非定常流动的收敛速度,但计算量增大;减缩频率越小,动导数辨识难度越高。

The dynamic characteristics of airbreathing hypersonic airframe/propulsion integrative vehicle under supersonic flight conditions was numerically studied by using 3D unsteady Navier- Stokes equations. The 2-order Roe scheme and the dual-time-step method based on LU-SGS were respectively applied to discreting the spatial and time derivative of unsteady flow. Based on the unsteady Etkin pneumatics model, the dynamic force-harmonic simulation was used to develop direct-dynamic stability derivatives. After using basic finner missile configuration to demonstrate the method, the numerical simulation investigation of dynamic characteristics of hypersonic integrative vehicle with internal and external flow was presented. That is to say, the cross- influence of transverse impact is obvious. The sensitivity analysis of the dynamic force-harmonic simulations for time steps, inner-iteration steps and reduced-frequency was included. The result shows that it can improve the convergence rate of unsteady flow to reduce time step and increase sub-iteration step-number. The smaller is the shrinkage-frequency, the higher is the difficulty of dynamic derivative identification.