Vortex-Induced Air Entrainment Rates at Intakes

Abstract

This paper presents an intrinsic approach to estimate air entrainment rates due to intake vortices based on large-scale laboratory measurements. Quasi-continuous measurements of the amount of entrained air were conducted using a sophisticated de-aeration system. The data analysis of 34 experimental runs resulted in a parameter fit describing the air entrainment rates at horizontal intakes. Additionally, a prediction band is given that provides a handle to inspect probability aspects. Furthermore, an approach to determine the critical intake submergence is presented. These guidelines enable hydraulic design engineers to estimate both the amount of entrained air and the critical intake submergence at horizontal intakes, so that the efficiency and safety of pressurized waterway systems is further increased.