Features and Control of Submerged Horizontal Vortex in Stepped Dissipation Wells

Abstract

Unlike a horizontal intake vortex, a submerged horizontal vortex is not bounded by a free surface. It has an axial air core submerged in a vessel such as a dissipation well. Due to the motion of its bound point (where the vortex ends), the front wall of the dissipation well could be damaged by cavitation. The goals of this study are to (1) summarize general features underlying the formation and collapsing of horizontal vortices in dissipation wells; (2) identify the features of submerged horizontal vortices; and (3) propose potential measures to mitigate cavitation damage. Through scaling down experiments performed in a transparent dissipation well with two optical sensors, various boundary conditions have been carried out to accomplish this investigation. It was found that a wider inlet flow falling with mixed air can facilitate the generation of submerged horizontal vortices. The optimal mappings between the inlet discharge and the water head differential for maintaining the vortices have been summarized. Depending on different applications, two configurations are proposed to mitigate the adverse effects of submerged horizontal vortices.