逆向射流流场建立瞬态过程

Transient Establishment Process of Opposing Jet Flow Field

为研究高超声速来流下逆向射流流场建立过程及其瞬态特性,基于非定常Reynolds平均Navier-Stokes(unsteady Reynolds-averaged Navier-Stokes,URANS)方程,采用高精度数值格式编制了一套适用于高超声速复杂流动的计算程序。首先,利用经典实验验证了计算程序对包含激波干扰非定常流场模拟的可靠性。随后,深入研究了逆向射流开启后射流流场的建立过程。计算结果表明:仿真结果清晰再现了逆向射流流场建立过程及流场波系演化特征,整个流场波系结构变化非常剧烈,钝体壁面压力和热流急剧变化,气动阻力先是迅速降低至最小值,随后小幅上升至稳定值。此外,逆向射流总压比升高,气动阻力下降后将经历更为剧烈的波动才趋于稳定。

To investigate the establishment process of opposing jet and its transient influence on the spiked blunt body in hypersonic flows,an in-house code which employs high-resolution numerical schemes was developed to solve the unsteady Reynolds-averaged Navier-Stokes equations.At first,classical experiments were applied to validate the code in simulating complex flow field including shock interactions.Then,the establishment process of opposing jet was thoroughly investigated.The obtained results show that establishment process of opposing jet and complex shock wave evolutions are clearly presented.The flow features change dramatically during the whole process.Besides,the pressure and heat flux along the blunt body change rapidly and the aerodynamic drag firstly drops to a minimum value and then increases to a relatively larger stable value.Furthermore,increasing the total pressure ratio of opposing jet would lead to more severe fluctuation in aerodynamic drag after it drops.