MVG控制斜激波/湍流边界层干涉的大涡模拟

采用浸没边界法(IBM)对带有微型涡发生器(MVG)控制器的激波/湍流边界层干涉流动进行了大涡模拟(LES)。以来流马赫数为2.3的斜激波(由平板上方8°楔产生)为基本流动入射平板湍流边界层,通过在干涉区前布置MVG阵列来控制激波诱导的边界层分离。采用浸没边界法处理MVG的复杂几何,分析了MVG尾迹区平均流速度剖面,雷诺应力,瞬态旋涡结构。结果表明:时均流场显示MVG尾迹区存在一对对转的主流向涡,流向涡加剧了边界内的动量交换从而增加了边界层抗分离能力,而瞬态流场则反映出MVG尾迹区的剪切层由于Kelvin-Helmholtz(K-H)不稳定性会卷起为一列展向旋涡。

Large-eddy simulation of MVG controlled oblique shockwave/turbulent boundary layer interaction

A large-eddy simulation(LES) combined with immersed boundary method(IBM) of a micro vortex generator (MVG) controlled shockwave boundary layer interaction flow was carried out. The base flow was represented by the interaction of an oblique shock-wave (generated by 8° wedge above flat plate) and a spatially-developing Mach number of 2.3 turbulent boundary layer. A MVG array was deposited before the interaction region to control the shock-induced boundary layer separation. A ghost-point immersed boundary method combined with Cartesian grid was adopted to deal with the geometrical singularity of MVG. Time-averaged streamwise velocity, Reynolds shear stress, instantaneous vortical structures in the MVG wake region were analyzed in detail. Time-averaged flowfield showed that there was a counter-rotating primary streamwise vortex in the MVG wake, whose momentum transportation increased the boundary layer ability to resist separation. The instantaneous flowfield revealed that the shear-layer in the MVG wake could roll-up to a trail of spanwise vortex ring/arc through Kelvin-Helmholtz(K-H) instability