Experimental investigations of compressible vortex loops

The present study involves the shock wave and consequent vortex loop generated when a shock tube with various nozzle geometries is employed. It aims to provide quantitative and qualitative insight into the physics of these compressible phenomena. The geometries included two elliptic nozzles with minor to major axis ratios of 0.4 and 0.6, a 15 mm circular nozzle and a 30×30 mm<sup>2</sup> square nozzle. The experiments were performed for driver gas (air) pressures of 4, 8 and 12 bars. Schlieren, shadowgraphy, and particle image velocimetry techniques were employed to visualize and quantify the induced flow field