Dynamic motion of a compressible vortex ring

The dynamic motion of a compressible vortex ring is studied by using an optical shadowgraph. A vortex ring treated here is generated by the impulse of a shock wave emerging from the open end of a shock-tube into the atmosphere. A jet flow ejecting from the shock-tube follows behind the vortex ring. The vortex ring moves forward at a self-induced velocity of 135 m/s. A rearward-facing shock wave is formed inside the vortex ring. This shock travels upstream, and leaves the vortex ring. A very thin vortex ring appears on the front interface of the main vortex ring. The instability wave is entrained in the main vortex core filament, and amplified. The disturbed jet flow behind the ring passes through the inside of the ring. As the region between the main vortex core and the interface of the vortex ring is filled with turbulent vortices, the thin vortex ring moves rearward on the interface of the vortex ring. The vortex ring becomes turbulent-like.