| This thesis is, written in the paper format. It includes three contributions and this abstract presents a brief summary of these three contributions.; The first contribution introduces a new design concept for energy dissipation below flow regulators. Instead of using a single-leaf sluice gate, a double-leaf gate design has been suggested. Twenty one experiments were conducted for different offset ratios, submergence ratios, width ratios, angles of inclination and Froude numbers.; The second contribution presents a theoretical and experimental study of plane turbulent surface jets with finite tailwater depth. The momentum flux and the rise in the water surface elevation at the section where the surface jet attaches to the bed were evaluated theoretically. Nine experiments with different Froude numbers and offset ratios, were 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. The momentum flux of the forward flow in the surface jet was found to decay appreciably with the distance from the nozzle. This decay is shown to be due to the entrainment, of the return flow which has negative momentum and also due to the increase in the tailwater depth, further away from the nozzle, which produces this return flow. This study has contributed to an understanding of the behavior of turbulent surface jets when the ambient fluid has a limited extent.; The third contribution presents a theoretical and laboratory study of plane turbulent wall jets in shallow tailwater. The momentum flux, in terms of that at the nozzle, was evaluated theoretically. A theoretical expression for the depression in the water surface elevation at the gate (housing the nozzle) was also obtained. An extensive set of experiments, with different Froude numbers and tailwater depth ratios, was conducted to observe and quantify the growth of the wall jet, the decay of the velocity scale and the momentum flux and the variation of the volume flux. Also, experiments were conducted to measure the bed shear stress and the length of the re-circulating flow region and to evaluate the drop in the water surface elevation at the wall. The depression in the water surface elevation in the vicinity of the wall produced return flow with negative momentum which resulted in a considerable decay of the momentum flux of the forward flow in the wall jet. Expressions describing the different flow characteristics of the wall jet, based on the experimental observations, were developed. The experimental and the corresponding theoretical results agreed quite well. This study has contributed to an understanding of the behavior of turbulent wall jets when the receiving water body has a limited extent. (Abstract shortened by UMI.)... |
