Control of a Mach reflection-induced interaction using an array of vane-type vortex generators

Abstract

An experimental investigation was conducted to control a Mach reflection (MR)-induced flow separation in a Mach 2.05 flow using a 18 $$^{\circ }$$ shock generator (SG). The study was extended to four SG exit heights (g / w) of 0.87, 0.81, 0.725, and 0.66 primarily to study its effect on the extent of flow separation as well as on Mach stem height, with and without control. Two vane-type vortex generator configurations, namely the ramp vane (RV) with device heights $$h/\delta = 0.3, 0.5, 0.8$$ , and 1.0 and the rectangular vane (RRV) with $$h/\delta = 0.3$$ and 0.5, were studied for control. Each control device array was implemented 10 $$\delta $$ upstream of the separation location for no control. For stable MR interactions (i.e., $$g/w = 0.87, 0.81$$ ), the extent of separation and the reattachment shock strength are seen to decrease with increase in RV height (with $$h/\delta =1.0$$ device showing 17% reduction). However, for unstable MR condition (i.e., $$g/w = 0.725$$ ), RV devices of $$h/\delta = 0.8$$ and 1.0 become ineffective. The RRV2 device ( $$h/\delta =0.5$$ ), on the other hand, was found to be more effective in reducing the extent of separation in both the stable (31%) and unstable (24%) MR conditions. The effectiveness of each control device is also accompanied with an increase in height of the Mach stem. This is, however, not seen as a serious limitation since in such strong interactions it is more important to prevent or avert an intake unstart condition. The separation shock unsteadiness or the $$\sigma _{\mathrm{max}}/P_{\mathrm{w}}$$ value, on the other hand, is seen to increase considerably with controls and seems to be almost independent for $$h/\delta \ge 0.5$$ .