RMA-2

Two-Dimensional (Depth Averaged) Finite Element Model for Hydrodynamic Systems

 

Basic Equations

 

The model uses the full nonlinear Shallow Water Equations, depth averaged to two dimensions, together with the continuity equation.  Turbulent energy is represented by an eddy viscosity analogy.  Forces due to bottom friction, wind stress and Coriolis effects are also included.  The model is also capable of representing the influence of a fixed baroclinic distribution

 

Method

 

The approach used is the finite element method that represents the continuum as a series of discrete elements connected at nodes, and then develops a solution for the simplified system.  Elements consist of curved triangles and quadrilaterals.  An implicit solution scheme is used for time dependent systems.  Each solution step requires several iterations.

 

The advantages of this method include:

 

a)         The ability to represent irregular boundary configurations

 

b)         Variable mesh size, so that extra detail can be applied in areas of special interest.

 

c)         Direct solution of steady state problems and longer time steps with the implicit solution for dynamic problems.

 

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