| The complex shock wave/turbulent boundary layer interactions(SWTBLIs)are commonly encountered in the internal and external flows of an air-breathing hypersonic vehicle.SWTBLIs-induced separation is an undesirable phenomenon that causes severe pressure/heating loads and flow unsteadiness,posing a key challenge to the design of hypersonic vehicles.The investigations of hypersonic SWTBLIs not only face the lack of scaling methods for the canonical configurations but also require the simplification of three-dimensional complex configurations that represented by the inward-turning inlet.In the present work,the shock structures,flow separation and flow control of hypersonic SWTBLIs for typical configurations are investigated using a combination of numerical simulations,experiments and theoretical analyses.The scaling analyses of two-dimensional,axisymmetric and three-dimensional swept SWTBLIs,over a wide range of Mach numbers,Reynolds numbers and wall temperatures are conducted.For two-dimensional compression corners and shock reflections,a scaling analysis of the interaction length of hypersonic SWTBLIs is performed by accounting for effects of wall temperature on the separation criterion.Two scaling relationships are identified according to low and high Reynolds numbers for the hypersonic SWTBLIs.The hypersonic cases with high Reynolds numbers show a more rapid growth in the interaction length than that with low Reynolds numbers.For the cylinder-flare and cone-flare,the axisymmetric interaction lengths grow more rapidly than that of two-dimensional SWTBLIs.For the three-dimensional swept SWTBLIs generated by the sharp-fin,a new upstream-influence scaling is developed by considering the Reynolds number effects,which show good performance over a wide range of Mach numbers and Reynolds numbers.A simplified model called the oblique shock wave impinging on a concave halfcylinder is employed to investigate the SWTBLIs in the three-dimensional inwardturning inlet.The influences of the flow deflection angles of the incident oblique shock waves on the SWTBLIs are analyzed at a freestream Mach number of 6.The results indicate that the oblique shock wave/concave cylinder interactions can be characterized by sweeping,impinging and reflection of the shock wave.As the oblique shock sweeps the concave cylinder,the shock interaction type between the incident shock and the separation shock transits from Mach reflection to regular reflection.The mechanism of transition in reflection types is revealed by local two-dimensional analyses and an upstream-influence scaling for the swept shock/concave cylinder interactions is established.The three-dimensional separation with complex surface-flow patterns is generated in the coupling region of the shock sweeping and impinging,in which the tornado-like vortex gradually decreases and finally disappears with the increase of the deflection angles.A scaling of the interaction length is obtained on the concave halfcylinder.After the shock reflection,a streamwise counter-rotating vortex pair is generated by the collision of the upstream low-momentum fluid.The downstream evolution of the streamwise counter-rotating vortex pair is revealed.The impacts of boundary-layer bleeding and rectangular vanes on the large flow separation induced by the oblique shock wave impinging on the concave cylinder are investigated.The results indicate that the boundary-layer bleeding at the bottom of the concave cylinder can reduce the separation but the low-momentum fluid cannot be completely bled.Thus,the effectiveness of the boundary-layer bleeding in suppressing the convergence of the flow is not satisfactory.The influences of geometric parameters of boundary-layer bleeding are clarified,which led to an improvement in the design of the boundary-layer bleeding.The rectangular vanes installed on the sidewall of the concave half-cylinder can delay the separation of swept shock/concave cylinder interactions.The suppression of the convergence of low-momentum fluid to the symmetry plane is revealed by analyzing the geometric parameters of the rectangular vanes.Thus,a combination of boundary-layer bleeding and rectangular vanes is proposed,which not only eliminates the separation on the concave cylinder but also reduces the height of the low-momentum fluid at the exit significantly.The combination method provides an important reference for the flow control of the three-dimensional inward-turning inlet. |
