关键词: 剪切层, 激波, 卷吸涡, 扩散混合, 数值计算

Abstract: Upwind TVD scheme is used to solve laminar, 2D fully N-S equations.A shock diffracted by a cylinder or square cylinder along hydrogen air interface, and mixing enhancement in a shear flow are numerically studied.The results indicate that the shock travels faster in hydrogen.An adjustable shock and a swirling ovrtex appear in the shear region.After the swirling vortex impacts the cylinders, a reflected shock is formed, and hydrogen diffuses downstream in the region near cylinder walls.Contact surfaces are deformed and another vortex is generated.The distribution of hydrogen shows that the mixing is enhanced effectively by inserting cylinders along the interface, expecially for a square cylinder.The transition from RR to MR can be found for shocks traveling both in air and in hydrogen for a cylinder.Two Mach stems will transmit each other at the downstream.But in the case of a square column, the shock is almost not affected along the lower wall but Mach reflection takes place along the upper wall, then a diffracted shock and a Mach stem transmit each other finally.For both cases, the detached shock occurs on the right of cylinders.Similar shock structures arise, and contributions of cylinder shape are eventually forgotten.

Key words: shear flow, shock wave, swirling vortex, diffusive mixing, numerical simulatiop