Ehsan Parhizgar - Department of Civil Engineering, Yasooj Branch, Islamic Azad University, Yasooj, Iran
Zafar Namazian - Department of Mechanical Engineering, Yasooj Branch, Islamic Azad University, Yasooj, Iran

In this study, two-phase flow over a three-dimensional stepped spillway was numerically investigated using a finite volume code in ansys-Fluent commercial software. The numerical results were validated against experimental data. Then, the effects of several parameters were evaluated on the structure of the flow over the concerned spillway. Based on the natural roughness, several roughness heights of ۰.۰۰۰۱, ۰.۰۰۰۵, and ۰.۰۰۱ m were considered on the spillway surface to investigate the flow structure. In the next step, several surfaces with different contact angles, including ۸۰, ۱۲۰, and ۱۶۰°, were used. Finally, a passive control method, including simultaneous blowing and suction with different configurations, was applied to the steps of the spillway. The results revealed that a change in the surface roughness or contact angle and applying the control method could change the flow regime from skipping to nappe. Also, variations in the speed of falling water and energy loss were attributed to changes in the surface roughness and contact angle and implementation of the proposed control method.

Stepped Spillway, Rough surface, Hydrophobic to Superhydrophobic, Passive Control Method, energy dissipation, discharge, Falling Velocity