Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 1 2021 03 21 Numerical and Experimental Study of Wedge Elements Influence on Hydraulic Parameters and Energy Dissipation over Stepped Spillway in Skimming Flow Regime Numerical and Experimental Study of Wedge Elements Influence on Hydraulic Parameters and Energy Dissipation over Stepped Spillway in Skimming Flow Regime 185 200 3016 10.22060/ceej.2018.14587.5689 FA Kiyoumars Roushangar Civil Engineering Department, Tabriz University, Tabriz, Iran. Samira Akhgar Water Engineering Department, Faculty of Civil Engineering, Tabriz University, Tabriz, Iran Journal Article 2018 06 11 <strong>A stepped spillway is a hydraulic and cost-effective measure to dissipate the energy of large water flow over the spillway. Due to some limitations in stepped spillways, this study has intended a plan to increase and improve the effectiveness of energy depreciation. For this purpose, the effect of the wedge-shaped elements on the velocity and pressure changes over the steps, water level, and energy dissipation downstream the stepped spillway are evaluated.</strong><strong>In this regard, several forms of wedge elements are studied with changes in wedge arrangement and the rate of discharge by using a numerical model of Flow-3D, and the appropriate models from the aspect of the most energy depreciation are selected and studied in the laboratory.</strong><strong>In the laboratory, 25 experiments were performed on 5 physical models. Numerical and experimental results show that the addition of wedge elements on the stepped spillway has reduced the velocity and water depth downstream of the spillway to about 80% and 30%, respectively, and the energy dissipation over the stepped spillway increased by about 2.7 times. Also, by drawing the distribution profiles of pressure on the edge and the floor of steps, it was observed that the negative pressure in the horizontal section turned into a positive one. Also, negative pressure in the vertical section decreased up to 96% and positive pressure increased about 2 times. As well as increasing the density of the elements, the results that increase the energy dissipation are going to be more remarkable. </strong> <strong>A stepped spillway is a hydraulic and cost-effective measure to dissipate the energy of large water flow over the spillway. Due to some limitations in stepped spillways, this study has intended a plan to increase and improve the effectiveness of energy depreciation. For this purpose, the effect of the wedge-shaped elements on the velocity and pressure changes over the steps, water level, and energy dissipation downstream the stepped spillway are evaluated.</strong><strong>In this regard, several forms of wedge elements are studied with changes in wedge arrangement and the rate of discharge by using a numerical model of Flow-3D, and the appropriate models from the aspect of the most energy depreciation are selected and studied in the laboratory.</strong><strong>In the laboratory, 25 experiments were performed on 5 physical models. Numerical and experimental results show that the addition of wedge elements on the stepped spillway has reduced the velocity and water depth downstream of the spillway to about 80% and 30%, respectively, and the energy dissipation over the stepped spillway increased by about 2.7 times. Also, by drawing the distribution profiles of pressure on the edge and the floor of steps, it was observed that the negative pressure in the horizontal section turned into a positive one. Also, negative pressure in the vertical section decreased up to 96% and positive pressure increased about 2 times. As well as increasing the density of the elements, the results that increase the energy dissipation are going to be more remarkable. </strong> https://ceej.aut.ac.ir/article_3016_53a1320cb5d2f56130ad5222f93da374.pdf