Selective Withdrawal Hydraulic Study Using Computational Fluid Dynamics Modeling

Hydraulic study of a selective withdrawal relief gate is presented. A comparison study between a computational fluid dynamics model, Flow3D, and a 3D hydrodynamic model, EFDC, has been performed. Flow3D is applied to simulate behavior of the flow by using limited compressible flow approximations and RNG Turbulence model. EFDC is used to analyze the flow through the inlet using a shallow water solver configured equivalent to 2D Reynolds-Average Navier-Stokes (RANS) equations in vertical plane and Mellor-Yamada Turbulence Closure Scheme. Pressure heads and vertical opening velocity results from both models are compared. Computational fluid dynamic models provide us great insight to determine the hydraulic behavior and flow properties in these complex geometries. INTRODUCTION The purpose of this project is to provide selective withdrawal of water from a reservoir in order to control downstream water temperatures in an attempt to improve downstream fish habitat and water conditions. To accomplish this, a steel structure that bolts to the face of the existing intake towers and, together with the tower, forms a wet well that feeds water to the intake tunnel and discharge downstream through the pipe (see Figure 1). Figure 1. Selective Withdrawal Gates Layout 1808 World Environmental and Water Resources Congress 2013: Showcasing the Future © ASCE 2013