Interaction of supersonic wing-tip vortices with a normal shock

Abstract

An experimental study involving interaction of concentrated streamwise wing-tip vortices and normal shock fronts was carried out in a Mach 2.49 flow. The interaction scheme involved positioning a vortex-generator wing section upstream of a pitot-type normal shock inlet such that the wing-tip vortices interacted with the normal shock formed in front of the inlet. The vortex strength was varied by placing the vortex generator wing at different angles of attack while a normal shock was created by adjusting the mass flow rate passing through the inlet. Spark shadowgraphs, laser sheet planar visualizations, and pitot pressure measurements of the flowfield indicated a significant change in the structure of streamwise vortices generated by the vortex generator wing at 5.7- and 10.4-deg angle of attack upon encountering a normal shock discontinuity. Results of the Investigation showed that the interactions lead to the formation of an unsteady conical shock wave far upstream of the inlet as well as a highly turbulent flow downstream for both vortices. Pitot pressure measurements using a fast response pressure transducer in conjunction with the spark shadowgraphs revealed a bimodal feature of the flowfield. The frequency of oscillation of the generated structure was found to be higher for increased vortex strength. Measurements of pitot pressure in the vortex core in the absence of a shock wave revealed high-frequency oscillations that were attributed to the vortex meandering phenomenon.