The hydrodynamic numerical modeling is increasingly becoming a widely used tool for simulating the surface waterbodies including rivers, lakes, and reservoirs. A challenging step in any model development is the verification tests, especially at the early stage of development. In this study, a unique approach was developed by implementing the volume balance principle in order to verify the three-dimensional hydrodynamic models for surface waterbody simulation. A developed and verified three-dimensional hydrodynamic and water quality model, called W3, was employed by setting a case study model to be verified using the volume balance technique. The model was qualified by calculating the error in the accumulated water volume within the domain every time step. Results showed that the volume balance reached a constant error over the simulation period, indicating a robust model setup.
Part of the book: Direct Numerical Simulations
A brief overview of characteristics of stratified water bodies is followed by an in-depth analysis of the governing equations for modeling hydrodynamics and water quality. Equations are presented for continuity or the fluid mass balance; x-momentum, y-momentum, and z-momentum equations; mass constituent balance equation; the heat balance equation for temperature; and the equation of state (relating density to temperature and concentration of dissolved and suspended solids). Additional equations and simplifications such as the water surface equation and changes to the pressure gradient term are shown. Many of the assumptions that are made in water quality models are discussed and shown. Typical water quality source-sink terms for temperature, dissolved oxygen, algae, and nutrients are listed. A summary of some typical water quality models for lakes and reservoirs is shown. Two case studies showing how models can predict temperature and dissolved oxygen dynamics in stratified reservoirs are shown. The brief summary looks at ways to improve water quality and hydrodynamic models of lakes and reservoirs.
Part of the book: Inland Waters