Experimental Study on Some of Design Parameters Affecting the Hydraulic Behavior of Three-Sided U-Shaped Spillways

Document Type : Research Article



Three-sided spillways are used in dams as well as in irrigation networks, and water and wastewater Treatment plants. In this study, the effect of some major parameters on hydraulic behavior of flow in a three-sided V-shaped spillway and its side channel was evaluated using a physical model. The effect of changes in the end-sill height, the distance of the end-sill from the beginning of the side channel, and the side channel slope with different discharges were studied. Flow pattern and pressure fluctuations in the channel were considered as an indication of the flow behavior. Results showed that the end-sill height had the greatest influence on the intensity of pressure fluctuations and flow behavior in the side channel and increase in the end-sill height, decreased pressure fluctuations. Results also indicated that the location of end-sill from the beginning of the side channel, did not have considerable influence on pressure fluctuations. Moreover, increase in side channel slope up to about 3 percent decreased pressure fluctuations. However in slopes beyond 5 percent, pressure fluctuations increased again. Negative bed slopes decreased pressure fluctuations in the side channel considerably. It was also concluded that increase in flow discharge improved the flow condition in the side channel.