Three-Dimensional Free Surface Numerical Model For Hydrothermal Characteristic Studies

Date of Award




Degree Name

Doctor of Philosophy (Ph.D.)


Mechanical Engineering


The numerical modeling by using high-speed digital computers has become a powerful tool in simulating complex waste heat disposal problems.A three-dimensional thermaldynamics model has been developed. This model is coupled with a three-dimensional hydrodynamics model developed by Carter (1977) and has been used in this study. The combined model is time dependent and allows the water surface to deflect in response to wind shear, pressure gradients and Coriolis accelerations. A vertical stretched coordinate is adopted for better treatment of irregular bottom topography and the kinematic condition at the water surface. The momentum equations include the nonlinear convection terms but horizontal diffusion terms are omitted. However, the nonlinear convection, vertical and horizontal diffusion terms are all included in the energy equation. The difference scheme is written in the central-time, central-space format for the momentum equations and in the forward-time, central-space format for the energy equation. The DuFort-Frankel method is used for the vertical diffusion terms in both equations.The influence of vertical eddy viscosity, A(,v), on the tide- and wind-driven circulation has been studied. A larger A(,v) value can better dissipate the tidal energy both in amplitude and phase, and also enhance the vertical mixing of wind induced motion. The horizontal eddy diffusivity, B(,h), is a main factor for the thermal diffusion. The choice of B(,h) in this study is discussed. Wind decreases the thermal plume size by increasing the heat transfer rate between the air-water interface. The thermal plume shape changes in correspondence with the tidal stages. When two tides are imposed on opposite sides of the boundary, a ridge line is observed. The location of this line varies with time when the two tides are not in phase.The model has been verified at the Anclote Anchorage site of Florida Power Company. Results show that the model is capable of handling diverse meteorological conditions, severe bottom topography, very shallow water and strong tidal driving force.


Engineering, Mechanical; Energy

Link to Full Text