Rajarshi Das

Experimental Study of Supersonic Entrainment Using a Cavity

The effect of wall-mounted three-dimensional cavities on the entrainment of gaseous injectant into a supersonic stream of Mach number 1.7 is studied. Entrainment induced by flow unsteadiness, turbulence, and exchange of fluid between the cavity and mainstream flow has been investigated. To clarify the influence of the ratio of cavity length to width L/W on the fluid dynamic behavior, cavities of L/W ratios between two and four were applied at a constant length-to-depth ratio L/D. Acoustic oscillations generated from the cavity were observed to have profound impact on mass exchange between the cavity and the freestream flow. These acoustic oscillations were in turn found to be dependent on the L/W ratio of the cavity. Shift in dominant acoustic mode was observed as the L/W ratio was changed from three to four. Spillage of the shear layer over the cavity walls and turbulence induced in the cavity were probed by measuring velocity using laser Doppler velocimetry. Entrainment of secondary gaseous injection in...

Acoustic and velocity field over 3D cavities

Effects of wall mounted cavity on a Mach 1.7 freestream flow over it are investigated experimentally and numerically. Three different three dimensional (3D) cavity configurations have been used in the study. The results are compared with those of a two dimensional (2D) cavity. Flow field over the cavity is observed to depend intensely on the cavity width and on the allied aerodynamic flow structure in the vicinity of the cavity. Pressure oscillations generated by presence of wall mounted cavity in supersonic freestream was also observed to affect the fluid motion over cavities.