Investigation of a Fluidic Shock Control Method for Hypersonic Inlets

To realize the control of the ramp shock system of hypersonic inlets, the current study involves a fluidic shock control technique featured by fixed geometry. First, a theoretical analysis and design method for this technique is developed, including the calculation of the shock control requirement of a typical hypersonic variable inlet, the analysis of the shock control capability of a set of S-shaped surfaces attached to a ramp surface, the estimation of the required secondary-to-primary mass flow ratio, and the realization of an aerodynamic curved surface by distributed air injections. Then, the correctness of the method and the underlying flow mechanism are verified by computational fluid dynamics with a two-dimensional case. Finally, a three-dimensional test model is designed and investigated by experiments and computations to demonstrate the capability of the fluidic shock control technique, examine the three-dimensional effects, and verify the computational fluid dynamics tool. The results show that the shock control capability of this technique can meet the requirement of hypersonic variable inlets operating from Mach 4 to 6. At a secondary-to-primary mass flow ratio of 1 % or less, the first ramp shock can be consistently maintained on the cowl lip from Mach 5 to 6.