Two points velocity correlation of vortex ring by many points of simultaneous measurement using hot wire anemometer

When the vortex ring moves to some extent, circumferential waves occur in vortex ring and the amplitude of wave becomes big gradually. At last vortex ring deform and disappear. Study of vortex ring has been experimented by technique of the visualization. In the case of visualization, it is necessary to use the tracer. However, the tracer may influence something to vortex ring disappearance. Therefore this study measure the vortex ring without the tracer using hot wire anemometer. We produce the hot wire anemometer and device to measure circumferential waves. As the result, we were able to check the operation of hot wire anemometer and device.