Plane Turbulent Surface Jets in Shallow Tailwater

Abstract

This paper presents a theoretical and laboratory study of plane turbulent surface jets in shallow tailwater. The main objective was to show that when the depth of tailwater is finite, the momentum flux in the forward flow in the surface jet decays appreciably with the distance from the nozzle producing the surface jet. This decay is shown to be due to the entrainment of the return flow which has negative momentum and an increase in the tailwater depth further away from the nozzle produces this return flow. An extensive set of experiments, with different Froude numbers and offset ratios, was conducted to observe and quantify the growth of the surface jet, the decay of the velocity scale, and the momentum flux and the variation of the volume flux. On the whole, the results from this study highlight the effect of the tailwater depth on the behavior of plane turbulent surface jets when the ambient fluid has a limited extent.