超声速高度欠膨胀冲击射流的大涡模拟

Large eddy simulation of highly under-expanded supersonic impinging jet

冲击射流广泛应用于短距起飞垂直降落飞行器(SVTOL)等航空航天领域。本文采用大涡模拟方法对高度欠膨胀的超声速冲击射流的流场进行了数值模拟。本文数值模拟得到了高度欠膨胀冲击射流流场中的激波结构和内外剪切层中不同尺度的涡结构。数值结果观察到了马赫盘的振荡,以及在斜激波、马赫盘及大尺度涡结构的共同作用下,射流内外剪切层之间的环形激波的生成与消失的周期过程。并对流场内剪切层的涡结构的演化进行了研究,数值结果显示内剪切层的大尺度涡结构的形成与马赫盘的振荡相关,在内外剪切层的作用下形成了壁射流区内外交错的涡结构。

The study of under-expanded supersonic impinging jet has been a popular subject not only because of its fundamental importance but also its practical importance in aerospace applications,such as Short Take-off and Vertical Landing（STOVL）.In this paper,Large-Eddy Simulations（LES） of highly under-expanded supersonic jet impinging on large plate has been carried out.The numerical simulation successfully captures the shock wave structure in the jet plume and vortex structures with different scales in the internal and external shear layer and in the wall jet.The numerical results show the oscillation of the mach disk,and occurrence and disappearance of the annular shock in the peripheral supersonic flow during a period of oscillation.At the same time,through the numerical simulation,the evolution of the vortex in the internal shear layer has been observed.It can be seen that the formations of large-scale vortex structures associate with the oscillation of the Mach disk.Under the interaction of internal and external shear layer,the interlacing vortex structures in the wall jet are formed.