Keywords
Hydrodynamic model; CE-QUAL-W2 model; Lakes and reservoirs modelling; 3D numerical verification
Start Date
25-6-2018 9:00 AM
End Date
25-6-2018 10:20 AM
Abstract
In order to develop a three-dimensional version of the two-dimensional longitudinal-vertical hydrodynamic and water quality model CE-QUAL-W2, the hydrodynamic numerical solution scheme was expanded and modified to a unique 3D scheme. The 2D formulation of the CE-QUAL-W2 model is fully implicit and solves for the free surface elevation implicitly from the free surface equation, but the solution of the momentum equations treats the free surface elevation explicitly. In order to make both solutions linked in which the free surface elevation is treated either explicitly or implicitly at the same time step, the degree of implicitness was added to the 3D numerical solution of free surface and momentum equations. The implementation of the semi-implicit scheme in the present 3D model improved the fully implicit scheme by reducing the free surface wave damping of the numerical solution. This is a novel approach compared to other 3D models since the 3D hydrodynamic numerical solution was coupled with the numerical solution of heat and water quality so that hydrodynamics, temperature, and water quality were solved at the same time step. Analytical verification was performed to show that the 3D model agreed with the exact analytical solution for special cases. Additionally, the model predictions of water level, temperature, and dissolved oxygen were compared with field data from Cooper Creek Reservoir, Oregon, USA.
Water Level, Temperature, and Water Quality Numerical Predictions of a 3D Semi-Implicit Scheme for Lakes and Reservoirs: An Analytical and Field Case Study
In order to develop a three-dimensional version of the two-dimensional longitudinal-vertical hydrodynamic and water quality model CE-QUAL-W2, the hydrodynamic numerical solution scheme was expanded and modified to a unique 3D scheme. The 2D formulation of the CE-QUAL-W2 model is fully implicit and solves for the free surface elevation implicitly from the free surface equation, but the solution of the momentum equations treats the free surface elevation explicitly. In order to make both solutions linked in which the free surface elevation is treated either explicitly or implicitly at the same time step, the degree of implicitness was added to the 3D numerical solution of free surface and momentum equations. The implementation of the semi-implicit scheme in the present 3D model improved the fully implicit scheme by reducing the free surface wave damping of the numerical solution. This is a novel approach compared to other 3D models since the 3D hydrodynamic numerical solution was coupled with the numerical solution of heat and water quality so that hydrodynamics, temperature, and water quality were solved at the same time step. Analytical verification was performed to show that the 3D model agreed with the exact analytical solution for special cases. Additionally, the model predictions of water level, temperature, and dissolved oxygen were compared with field data from Cooper Creek Reservoir, Oregon, USA.
Stream and Session
Stream D: Modeling Environmental Fate of Contaminants, Human Well-being and Public Health
D1: Environmental Fluid Mechanics – Theoretical, Modelling, and Experimental Approaches