Influence of Turbulence Models on Simulated Flow Characteristics Over Ogee Spillways

Abstract

The study investigated the simulation of flow characteristics over an Ogee-type spillway surface. This research utilizes a Flow-3D numerical model that builds upon the findings from prior experimental data and numerical models simulated by Ansys with a Flow-3D k-epsilon turbulence model. It utilizes Flow-3D methods with RNG and LES turbulence models to analyze flow rate, water profile, pressure, shear stress, and velocity at seven points along the spillway. The study reports strong agreement between the RNG turbulence model's numerical results and experimental data, demonstrating that the numerical model accurately reflects the physical flow behavior. As the discharge increases, the pressure distribution decreases, demonstrating a clear relationship between flow rate and pressure distribution along the spillway. This analysis highlights two negative pressure regions: one at the Ogee curve and the other at the end of the sloping straight section beyond the curve. Error analysis reveals closely aligned results, comparing experimental data with Ansys simulations across various turbulence models for seven sensors. The mean absolute error (MAE) values for Ansys, k-epsilon, RNG, and LES are 0.0261, 0.0252, 0.0268, and 0.0278, respectively, while root mean squared error (RMSE) values are 0.0269, 0.0279, 0.0283, and 0.0299, respectively, indicating good consistency with experimental findings. Additionally, comparisons of velocity distribution within Flow-3D, utilizing models such as k-epsilon, RNG, and LES, reveal MAE values of 0.0846 for RNG and 0.1382 for LES, alongside RMSE values of 0.0984 for RNG and 0.1552 for LES, highlighting the precision of the data. This study highlights the flow dynamics of Ogee spillways, demonstrating Flow 3D's accuracy in modeling discharge, design effects on pressure distribution, and cavitation risk.