GENERATION OF A VORTEX RING WITH HIGH REYNOLDS-NUMBER BY AN EXPLODING WIRE IN WATER

A method is presented for generating a vortex ring in water by an exploding wire installed in a metal pipe. As a vapor bubble accompanied by wire explosion grows, water starts to flow with a high speed resulting in a formation of a vortex ring at the outlet of the pipe. The growth speed of a vapor bubble by the exploding wire in water is measured as 10 similar to 20 m/s, in consistent with measurements of the translational velocity, 4 similar to 5 m/s, of vortex ring and the rotational velocity, about 10 m/s, of fluid at the edge of vortex core. The Reynolds number based on the diameter of orifice, the velocity of vortex ring and the kinematic viscosity reaches the order of 10(5). The magnitude of vorticity and the circulation are in the order of 10(3)/s and 10(-1) m(2)/s. These values are larger by about 10 times than those reported previously.