Swirl Motion of a Water Jet in a Water Bath of Linearly Increasing Depth

Abstract

Two types of swirl motions of a liquid jet occur when a liquid is injected through a centered bottom nozzle into a cylindrical bath of a constant depth: shallow-water and deep-water wave types. The water in the bath is drained and then circulated with a pump to keep the bath depth constant. Similar swirl motions can be observed when a liquid is continuously injected into a cylindrical bath without draining it from the vessel. The bath depth therefore increases linearly with time. The swirl motion of the deep-water wave type is useful for practical applications because it has very high mixing efficiency. In this study the trajectory of the swirling jet, the velocity vectors of water and air flows, and the period and amplitude of the swirl motion in a bath of varying depth are experimentally and numerically obtained The results are compared with those for a swirl motion generated in a bath of constant depth.