Examination of Flow in a Chute Spillway During Flood Conditions Using a 3D Numerical Model

Abstract

Dams are built for many purposes, one of the most important of which is to reduce the impact of floods. They release water downstream in a controlled manner through spillway structures. Spillways are critical structures that must be designed with low-risk criteria to withstand floods that occur once every thousand years. This paper presents a three-dimensional CFD simulation of the flow over a prototype spillway and validates the results with experimental data. The spillway belongs to the & Ccedil;atalan Dam, which was constructed in 1985 for hydroelectric power generation. A 1:100 physical model of the & Ccedil;atalan Dam spillway was built based on Froude similarity, and velocities in the discharge channel were measured at specific cross-sections and points. The numerical model used the Volume of Fluid (VOF) method and the k-epsilon Standard model. The velocity values from the numerical model were compared with experimental velocity values, showing good agreement. Additionally, pressure values were obtained from the numerical model, and cavitation index values were computed accordingly. The results indicated no cavitation risk in the prototype spillway, as the index values remained above 0.2 at all points in the cross-sections.