Effect Of Wall Roughness Element On The Flow Of Hypersonic Blunt Wedge Under Small Angle Of Attack

The purpose of this paper is to study the effect of the small attack angle on the flow around the wall of a hypersonic blunt wedge.Assuming the flight height is 29 Km and the number of Ma is 6,nine attack angles are designed for 0 °,0.25 °,0.5 °,0.75 °,1 °,1.25 °,1.5 °,1.75 ° and 2 °.The two-dimensional N-S equations are divided into non-viscous,viscous and unsteady terms.It uses the fifth-order WENO scheme to discretize the unsteady term,uses the six-order central difference schemeto discretize theviscousterm,and uses the three-step third-order TVD Runge-Kutta method to discretize theunsteady term.Furthermore,direct numerical simulation of the flow field is carried out.The results show:A single K-type roughness element causes the formation of a shock-expansion-shock wave in the flow field,while a single D-type roughness element causes an expansion wave-shock-expansion wave in the flow field.And the effect of K-type roughness on the flow field is larger than that of D-type roughness element.The position of the strong shock at the small attack angle leeward surface is continuously moved forward.The strong front edge of leeward surface is stronger and the trailing edge of windward face is stronger.In the flow field downstream,the first weak shock wave and the second expansion wave position of the leeward surface flow field are shifted backward while the first weak shock wave and the second expanded wave position of the windward surface are shifted forward.The larger the angle of attack is,the smaller the free-flow velocity is in the boundary layer.On the windward side,the larger the angle of attack is,the smaller the thickness of the boundary layer is.