Numerical and experimental study on opposing jet in hypersonic flow

As an active flow control technology, the opposing jet has become a research hotspot due to its broad prospect in reducing aerodynamic heat. In order to explore the heat flux reduction law and related mechanism of opposing jet flow control for hypersonic vehicles, a hemispherical bluff body model was studied by numerical simulations and wind tunnel experiments under different freestream and opposing jet conditions. The flow field and Stanton number distribution on the model surface were obtained, and both numerical and experimental data were verified against each other. The results suggest that, the heat flux reduction effect of the opposing jet is the consequence of a combined action of the jet backflow and the jet pushing away the front shockwave from the head. At a fixed Mach number, the heat flux reduction effect of opposing jet becomes more obvious with the increase of the jet pressure ratio; while under the condition of a similar jet pressure ratio, better heat flux reduction effect by the opposing jet can be achieved at higher Mach numbers.