Numerical Analysis of Cavitation Dynamics on Free Ogee Spillways Using the Volume of Fluid (VOF) Method

Simulating complex hydraulic conditions, particularly two-phase flows over spillway chutes, can be achieved with high accuracy using three-dimensional numerical models. This study investigates the potential for vacuum generation and cavitation phenomena on the Aghchai Dam service spillway through numerical simulations conducted in Flow-3D. The analysis focuses on two specific flow rates, 4400 and 1065 cubic meters per second, as determined by experimental data. The Volume of Fluid (VOF) method is employed to accurately calculate the free surface flow. Simulation results at a discharge rate of 4400 cubic meters per second indicate a high likelihood of cavitation at critical locations, including the ogee curve and the angle transition in the chute channel. These areas require specific mitigation measures to prevent cavitation-induced damage. In contrast, at the lower flow rate of 1065 cubic meters per second, the risk of cavitation is minimal due to reduced flow velocity and the absence of flow separation from the bed. The numerical findings align closely with empirical observations, demonstrating the reliability of the simulation approach in predicting cavitation behavior.