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ISSN オンライン: 2642-0554

THE VORTEX RING IMPINGING ONTO A GROUND SURFACE

Taiichi Nagata


Shinnosuke Obi
Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

Shigeaki Masuda
Department of Mechanical Engineering, Keio University, 3-14-1, Hiyoshi, Kouhoku-ku, Yokohama, 223-8522, Japan

要約

As a part of the laboratory experiment on a micro-burst, the instantaneous velocity fields of an impulse-driven vortex ring impinging onto a normal wall have been investigated. The air flow has been visualized by filling ethylene glycol smoke. The instantaneous velocity fields induced by a vortex ring were measured by employing the PIV in which the cross correlation method was used.
It was shown the interactions between primary vortex ring and induced secondary vortex ring. The horizontal and vertical velocity distribution across the vortex core was discussed. The time evolution of circulation in vertical cross section can be fitted to the theoretical equation for that of incompressible viscous vortex. These results were validated by comparison with the atmospheric microburst.