Study On The Flow Of The Boundary Layer Around The 0 Angle Of Attack Hypersonic Rough And Blunt Cone

The roughness and rough element have a significant effect on the aerodynamic characteristics of the aircraft.In this paper,the direct numerical simulation method is used to study the winding flow problem of hypersonic rough and blunt cone boundary layer under the condition of 0 attack angle,the head radius of the blunt cone model is n=1mm,the half cone angle is 6,and the Mach number of the flow is 6.The results show that the thermodynamic parameters change obviously due to the existence of strong shock wave in the head and near the front edge.When there is a protruding or sunken rough element on the wall surface,the wall flow is greatly affected by the rough element,and the shock wave and expansion waves are generated,and different types of rough elements change the order and position of the shock wave and expansion wave.When the boundary conditions of wall temperature are changed,it can be found that the variation of the flow parameters of the two boundary conditions of isothermal wall and adiabatic wall is basically the same.The difference is that under the two conditions,there is a great influence on the wall parameters at the rough element position,and the wall density is much larger than that of the adiabatic wall condition under the isothermal wall condition,and the maximum difference is 10 times.The isothermal wall boundary conditions will increase the thickness of the boundary layer,especially in the blunt cone head,rough element position and the tail of the blunt cone more obvious,the boundary layer thickness increases by about0.1mm on average.When the flight altitude is changed,the effects on the whole flow field,different section pressure,wall parameters and boundary layer thickness are studied.The results show that it is greatly affected by flight altitude at the position of rough element,and with the increase of flight altitude,it has the effect of amplifying the shock wave and inhibiting the expansion waves.And the flight height increased from 20 km to 28 km,so that the boundary layer thickness increased more and more,in the blunt cone head and tail increase amplitude reached the maximum,wherein the maximum increase of boundary layer thickness reached 0.17 mm.