INTERACTION OF SUPERSONIC WING-TIP VORTICES WITH A NORMAL SHOCK

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-generat or 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 ge nerator wing at different angles of attack while a normal shock was cr eated by adjusting the mass flow rate passing through the inlet. Spark shadowgraphs, laser sheet planar visualizations, and pitot pressure m easurements of the flowfield indicated a significant change in the str ucture of streamwise vortices generated by the vortex generator wing a t 5.7- and 10.4-deg angle of attack upon encountering a normal shock d iscontinuity. Results of the investigation showed that the interaction s 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 v ortices, Pitot pressure measurements using a fast response pressure tr ansducer in conjunction with the spark shadowgraphs revealed a binodal feature of the flowfield, The frequency of oscillation of the generat ed structure was found to be higher for increased vortex strength. Mea surements of pitot pressure in the vortex core in the absence of a sho ck wave revealed high-frequency oscillations that were attributed to t he vortex meandering phenomenon.