Experimental Study of the Formation of a Vortex Ring at the Open End of a Cylindrical Shock Tube

Abstract

Schilieren spark snapshots spaced at electronically controlled intervals of several hundredths of a millisecond show the emergence of the shock wave and the formation of the vortex ring at the end of a cylindrical shock tube, open to the atmosphere. The axial positions of the vortex ring and shock front are plotted as a function of time for the first millisecond, in which time the vortex forms and is accelerated to about three-quarters of the theoretical particle velocity of the mass flow following the initial plane shock. The diameter of the vortex ring increases nonlinearly with time and distance.