大推力系数超声速反向射流流动结构研究

Numerical simulation was carried out using detached eddy simulation（DES）method in order to research the flow structure of the supersonic opposing jet with high thrust coefficient（C_t=4）. A single nozzle configuration based on NASA Langley cold flow experiment was selected and post-process methods such as time averaging flow analysis and flow structure visualization were applied. The results show that under the condition of high thrust coefficient，the opposing jet presents a stable short penetration mode（SPM），which presents a large-angle cone shape. The expanded jet terminates through a Mach disk（or the jet terminal shock）and reverses its orientation as a conical free mixing layer. Early K-H vortex flow characteristics appeared in the conical mixing layer but cannot observe the typical K-H vortices. Flow structure visualization techniques show vortices break up occurs at the edge of the Mach disk，which is a main source of aerodynamic disturbance in the subsonic reverse flow zone.