3D Finite Element Modeling of Free-Surface Flows with Efficient k – ε Turbulence Model and Non-hydrostatic Pressure

Abstract

Validation of 3D finite element model for free-surface flow is conducted using a high quality and high spatial resolution data set. The present research finds its motivation in the increasing need for efficient management of geophysical flows such as estuaries (multiphase fluid flow) or natural rivers with the complicated channel geometry (e.g. strong channel curvature). A numerical solution is based on the unsteady Reynolds-averaged Navier-Stokes equations without conventional assumption of hydrostatic pressure. The model uses implicit fractional step time stepping, with the characteristic method for convections terms . The eddy viscosity is calculated from the efficient k – ε turbulence model. The RANS are solved in the multi-layers system (suitable for the vertical stratified fluid flow ) to provide the accurate resolution at the bed and free-surface. The model is applied to the 3D curved open channels flows for which experimental data are available for comparison. Good agreement is found between numerical computations and experiments.KeywordsValidationCharacteristic method3D Curved open channelsecondary currentsNon-hydrostatic pressure