Author(s): Gregory Guyot; Amaury Pittion-Rossillon; Antoine Archer
Linked Author(s): Grégory Guyot
Keywords: Free surface vortex; Physical scale modeling; CFD; Water intakes; VOF method
Abstract: Until now the fine representation of the complex hydraulic phenomena such as Vortices have been related mainly to physical modeling for industrial purposes. EDF has been testing the 3D CFD code “Flow 3D” for free-surface flow simulation for five years. The main difficulty of using finite elements programs is the relevance and the stability of their numerical results. In the field of vortices, it has been decided to test how reliable Flow 3D is. Flow 3D is a commercial CFD Code using VOF method with a rectangular mesh. In this study it is assumed that flow is liquid water with an interface simulated by VOF method. This study is based on a schematic hydraulic experimental model realized in the EDF-R&D laboratory. The chosen case is a simple configuration of a vertical downward drain hole. The basin is one meter long and around a half meter wide. The water level is fixed and the flow rate is adjustable. The main advantage of this experiment is that the geometry is easy to simulate with 3D CFD software. In this configuration it is ensured that a free vortex phenomenon does exist. Different types of vortices have been chosen for the validation case. The aerated vortex length for the maximal case reaches the basin bottom. The first goal of the 3D CFD simulation is to check if Flow 3D is able to represent a vortex when it physically exists. The second objective is to find out a simplified method that enables to represent the vortex as it appears in the physical experimentation. The third one is to propose a numerical method that allows the engineer to predict the vortex type for a preliminary design of a hydraulic structure.
Year: 2014