Research On Characteristics Of Terminal Shock Wave/Boundary Layer Interactions In Supersonic Bump Inlet

Bump inlet is commonly used in advanced supersonic fighters.When it works normally,the terminal shock wave will inevitably interact with the boundary layer on the bump surface,forming a complex three-dimensional shock wave/boundary layer interaction flow.In this paper,the numerical and experimental methods are used to investigate the terminal shock wave/boundary layer interactions within bump inlet.Furthermore,the influences of the cowl configurations on the flow are studied.Firstly,the terminal shock wave/boundary layer interaction within a typical Bump inlet is studied under the design and non-design conditions.It is found that the terminal shock wave/boundary layer interaction flow appears as quasi-two-dimensional interactions near the symmetry plane on critical and supercritical state under the designed Mach number,and a recirculation structure is formed near the sidewall.On the critical state of sub-designed Mach number,the recirculation zone near the sidewall still exists,but the low energy flow displacement effect near the symmetry plane is enhanced.On subcritical state of designed Mach number and critical state of super-designed Mach number,the interaction flow is completely dominated by the sidewall recirculation zone.Secondly,the influences of aspect ratios of bump inlet on terminal shock wave/boundary layer interaction flow are studied.The results show that as the inlet aspect ratio increases from 1 to 3,the relative influence of the sidewall recirculation zone on the entrance separation structure is weakened,and the separation on the symmetry plane gradually transforms from dramatic three-dimensional to quasi-two-dimensional separation to three-dimensional.And the distortion increases with the total pressure recovery coefficient decreasing from 0.8986 to 0.8658.Therefore,the increase of the aspect ratio will deteriorate the overall aerodynamic performance of the inlet.Then,the influences of the cowl configurations on the terminal shock wave/boundary layer interaction flow were investigated.The results show that as the sweep angle of the cowl increases from-12.4° to +12.4°,the sidewall recirculation zone is widened,when the sweep angle increases to 6°,the flow is completely dominated by the recirculation zone near side wall.Correspondingly,with the increase of the sweep angle of the cowl,the distortion of the outlet increases,and the total pressure recovery coefficient increases from 0.8920 to 0.9121.For the bump inlets with different sweep angle of the side wall,once the sweep angle deviates from the reference model(sweep angle = 45°),the terminal shock wave/boundary layer interaction flow is dominated by the recirculation zone near the side wall.With the increase of the sweep angle of the side wall,the flow field distortion of outlet first decreases and then increases,while the total pressure recovery coefficient increases from 0.8909 to 0.9009.Finally,three bump inlet models with different cowl sweep angel are designed,and the free jet wind tunnel experiment is carried out.And it is found that the sidewall recirculation zone increases with the increase of the sweep angle of the cowl,the tripple point of "?" shock moves away from the wall,and the entrance boundary layer displacement effect is also gradually enhanced.