A model for three dimensional density stratified flow

This report describes the computer models modified and developed under contract #DACW39-85-C-0085 issued by the United States Army Corps of Engineers, Waterways Experiment Station. This report is separated into series of chapters describing: a) the governing equations for all approximation types. b) the finite element formulation c) the example problems d) the model user instructions. Finally an appendix details the full finite element formulation for all the element types. In order to describe stratified flow (due to salinity or thermal influences) in three dimensions, the governing equations must describe velocity in all three cartesian directions, water pressure and the distribution of salinity or temperature throughout the system. A suitable set of equations can be achieved by combining the Reynolds form of the Navier Stokes equations, the volume continutity equation, the advection of diffusion equation for salinity or temperature transport and an equation of state relating water density to salinity or temperature. For the purposes of this description the equations will be describted in terms of salinity, an exactly parallel development is possible if temperature is treated as the dependent variable.