Numerical simulation of hypersonic flow over a sphere with surface injection

Numerical simulation of hypersonic flow over a blunt body is carried out for the purpose of examining the effect of surface injection flow in promoting turbulence effect in the boundary layer. In the calculation, injection flow is assumed to be turbulent according to the Park’s injection-induced turbulence model which is implemented in an appropriate oneequation turbulence model. Obtained numerical results are compared with existing experimental data on the velocity profile in the boundary layer. It is shown that a turbulent boundary layer develops when surface injection flow is introduced, even for a laminar upstream flow. A reasonable agreement is obtained for velocity profile at the vicinity of solid wall, but a large discrepancy is seen in the middle of boundary layer. Efforts are made to improve the agreement by changing injection rate, time constant of porous material, and free stream eddy viscosity, but none gives a totally satisfactory agreement. Inability of the turbulence model in calculating a boundary layer flow with a favorable pressure gradient is suggested as the probable cause.