The effect of member spacing upon the base pressure distributions recorded on perpendicular flat plates

Abstract

356tograph of a shear layer composed of argon at M= 3.1 and nitrogen at M= 1.7. Both streams have the same speed of 480 m/s. Thus the turbulent structures in the far field are expected to travel also at 480 m/s. On the figure, arrows indicate turbulent features of the flow and their displaced position. It is seen that in a time interval At= 17.4 gs, the features moved a distance Ax=8.6 ram. The convection velocity is simply U c =/Ix~At = 480 m/s, which agrees with our expectation and proves the accuracy of the system. A case with large velocity difference is shown on Fig. 3b, where a stream of helium at M= 1.7 mixes with a stream of nitrogen at M = 3.1. The convective velocity in this case is Uc = 640 m/s, surprisingly close to the lower freestream velocity. These pictures were recorded on Kodak Tri-X Pan, Experiments in Fluids 7 (1989) 400 ASA film. The ASA was boosted to 1,600 by developing the film with diafine.