Optimization of Stepped Spillways by Studying Pressure and Turbulent Kinetic Energy

Pressure distribution on the step spillways is an essential factor for determining the cavitation damage in step spillways. Negative pressure at the spillway surface causes cavitation problems, so the location of negative pressure is critical in measuring the cavitation risk. Turbulent kinetic energy is also an essential consideration for measuring the intensity of turbulence over the spillway surface; for this purpose, numerical modelling is done by using four types of step spillway models by varying channel slopes (12.5°, 19°, 29°,35°) by using the volume of fluid (VOF) and realizable k-ε model. The results indicated that negative pressure occurs at the perpendicular face of the step near the edge of the step in all channel slopes. With the move up in the channel slope, the possibility of cavitation is reduced. Turbulent kinetic energy profiles rise with the surge in channel slope. Turbulent kinetic energy is increased from the crest to the bottom of the spillway. At the bottom of the spillway, turbulent kinetic energy is more like a crest. The rise in channel slope caused maximization in the turbulent kinetic energy and the air fraction profiles over the spillway surface. Air fraction profiles have a relationship with turbulent kinetic energy.