The Investigation On The Control Of Shock/boundary-layer Interaction Based On The Micro-vortex Generator

As a ubiquitous phenomenon encountered in high speed flight, the shock/ boundary layer interaction (SWBLI) has considerable impact on the vehicle and component performance, especially in the scramjet inlet. The unsteady large-scale separation has become one of the critical problems, which would depress the performance of the inlet, and even lead to inlet unstart. The present research studied the flow control mechanisms of SWBLI with the micro-vortex generator, which was considered to be a promising device for its efficiency and robustness. Through experiments with the nanoparticle-based planar laser scattering (NPLS) technique, supersonic particle image velocimetry (PIV) and hybrid RANS/LES simulation, the mentioned flow field was invested in detail.As a tough obstacle and the precondition of experimental studies, the supersonic quiet wind tunnel was designed and built considering the demand of optical measurement to support the studies of the mechanisms of boundary layer transiton and the SWBLI, and finally the high quality laminar flow field was obtained. The complete laminar boundary layer in the supersonic quiet wind tunnel was inspired to get the appropriate turbulent boundary layer in the concerned region. The detail vortex structures in the turbulent boundary layer were captured by the NPLS technique, and the velocity field was analyzed with the PIV technique.The Recycling-rescaling method was used in the hybrid RANS/LES simulation to get the unsteady turbulent inflow condition, and the instantaneous flow structures was captured, containing the strips of low- and high- speed fluid, vortex structures and other large scale structures of the boundary layer. The immersed boundary layer method was imported successfully to assist the generation of high quality structured grids for the complex blocks. The improvements above have obviously enhenced the ability of hybrid RANS/LES on the simulation of wall turbulence.In the experimental studies of SWBLI, the high spatiotemporal resolution flow images and velocity field of SWBLI were captured utilizing NPLS and PIV technique. The difference in the scale of turbulence structures between the attached and separated case were observed. The spanwise structures of SWBLI were discovered both in the experiments and hybrid RANS/LES simulations, and it was supposed to be correlated to the strips structure beneath the turbulent boundary layer.To clarify the divarication on the instantanoeuse structures and dynamics behaviors of the wake flow after the micro-ramp, the detail field was detected from different directions with the NPLS. Comparing with the simulation results, instantaneous unsymmetrical of the counter vortex pair was found, as well as the K-H instability on the interface of the wake flow and the surrounding main flow, which accelerats the instability of the vortex pair, enhanced the dissipation,and finally makes it break into vortex rings. It was also found that the wake flow meanly come from the inner part of the turbulent boundary layer, which may get in more benefit from gathering the low speed flow and make the boundary layer robuster.The flow field of SWBLI under the control of micro-ramps was studied by the NPLS,PIV and hybrid RANS/LES simulation. The interaction between the vortex rings and the reflected shock wave, as well as the changing of the velocity and vorticity distribution in the field of the SWBLI were discorved. It was concluded that the micro-ramp could minish the separation induced by the incident shock wave under different mechanisms, varying with spanwise locations, which could be summarized as improving the boundary layer condition upstream the SWBLI and enhencing the transporting effect between the outer part and inner part of the SWBLI field through the vortex rings.