Control of three-dimensional separation due to sharp fins using co-rotating vanes ahead of quasi-conical and conical zones

Abstract

This experimental investigation studies the effect of an array of 30o inclined co-rotating vanes in controlling a three-dimensional interaction generated by a 15o semi-infinite sharp fin at Mach 2.05. The array is located upstream of the quasi-conical and conical zones of interaction. Primary objective is to study variation in (i) vane chord length c/h=7.2,4.2,2.5 and, (ii) vane height h/δ=0.3,0.5,0.75 for c/h=2.5 case in controlling the interaction. Control with the smallest chord length of c/h=2.5 and h/δ=0.75 shows the most promising result relative to vanes with longer chord lengths. The vortex trails from this configuration penetrate deeply into the quasi-conical zone of interaction thereby modifying it both azimuthally and radially. The plateau pressure in the conical region of interaction shows reduction of approximately 60% with an accompanied reduction in separation shock strength by nearly 70% for this case. Implementing control in either quasi-conical or conical zones reduces the overall control effectiveness considerably. Removing vanes ahead of quasi-conical zone reduces the effectiveness of favourably modifying the flow development in this region. The bow shock formed ahead of the first vane interacts with the three-dimensional interaction creating a pressure jump that separates the region of vortex influence from that of no control.