The study investigated the simulation of flow characteristics over an ogee-type spillway surface. The study's primary goal is to simulate and analyze flow characteristics over an ogee-type spillway, commonly used in water engineering for controlling water flow over a dam or weir. The study focuses on how flow rate changes with different conditions, analyzing how the water level changes along the spillway on the other side. Also, investigating how pressure varies across the spillway surface, understanding how the velocity of the water changes along the spillway, and analyzing the shear stress acting on the spillway surface. The study uses the Flow-3D software to perform numerical simulations. The software utilizes an RNG and LES turbulence model to represent turbulent flow conditions. The choice of this model is expected in Computational Fluid Dynamics (CFD) for simulating turbulent flows. The results are compared with observed data from literature as experimental and numerical simulation. Experimental and simulation data by ANSYS software studied by (Kanyabujinja, 2015). Also, the numerical simulation result of turbulence model "𝑘−𝜀" obtained by (KARIM, 2017). Good agreement is reported between the numerical results by using turbulence model (RNG) compared to experimental results. This signifies that the numerical model effectively mirrors the behavior of the physical flow. The results suggest that the pressure distribution is reduced as the discharge increases and vice versa. This indicates a relationship between flow rate and pressure distribution on the spillway and identifies two regions of negative pressure within the flow domain. The first is located at the ogee curve, and the second is observed at the end of the sloping straight line beyond the ogee curve. To address these findings, it was suggested that the slope of the spillway's horizontal surface could be reduced, or the ogee formula changed. Negative pressure zones can have implications for cavitation, a concern in spillway design. The slope of the spillway surface after the ogee crest is noted to influence pressure distribution and potentially prevent cavitation issues. In conclusion, this study offers valuable insights into the flow characteristics of ogee-type spillways. It effectively demonstrates the accuracy of numerical modelling software, specifically Flow-3D, in representing the system's physical behavior. Moreover, it underscores the significance of comprehending the impact of discharge and spillway design on pressure distribution and cavitation risk.
