Investigation of the Flowfield Created by the Interaction of a Sonic Jet and a Co-Flowing Supersonic Stream

摘要

Flowfield characteristics created by a sonic flow expanding freely between two supersonic streams were investigated experimentally using optical and pressure instrumentation. The base flow produced by the expansion of the streams around the base regions is compared to experimental data and theory by Chow. The shear layer created between the sonic and supersonic stream was also studied using Schlieren photographs is examined in an effort to explain the observed flow phenomenon. It was observed that a shear layer crossing a shock wave spreads and increases its turbulence level. However, an undesirable loss in total pressure results which could be undesirable. It appears that Chow's theory on base pressure approximates the characteristics of the flow near the end of the nozzle assembly where the two flows initially interact. The same trends were observed in the behavior of base pressure with increasing secondary total pressure as Chow observed during his experiment. The convective Mach number concept was successfully applied to the sonic injection geometry and it was demonstrated that the convective Mach number decreases drastically as the secondary pressure is increased. This is an indication that the growth rate of the shear layer increases, giving a faster mixing rate. Keywords: Supersonic combustion; Shock waves; Two-dimensional flow; Shear layer; Flow mixing. Theses. (EDC)