Flow and hydraulic efficiency of vertical intake structures

Abstract

This thesis presents the results of an extensive experimental investigation into the hydraulic efficiency of a vertically-oriented water intake. Water supplied from rivers and reservoirs is usually drawn through intakes. Under low submergence conditions, the operation of an intake is associated with the formation of surface vortices, which result in flow reduction and the downstream entrainment of air and swirl. The experimental work considered the fact that vortex formation is governed by the geometrical characteristics of the intake (e.g. diameter, shape, submergence, surrounding boundary, etc.) and the approaching flow conditions. Therefore, the experimental study was conducted to investigate the influence that the local shape and the proximity to boundaries each have on the hydraulic performance of a water intake. The results of the present experimental program have lead to a better understanding of the phenomena that govern the flow in such structures and to the elaboration of improved design guidelines.