The iterative solver

In 1D cases, the wave-induced set-up is calculated in SWAN with a simple trapezoidal rule.


In 2D cases, the Poisson equation of the divergence-free force field is solved in SWAN with a modified Successive Over Relaxation (SOR) technique (Botta and Ellenbroek, 1985). The boundary conditions for this elliptical partial differential equation are:

• at open boundaries: equilibrium between wave force and hydrostatic pressure gradient normal to the model boundary,
• at last grid points before shoreline: equilibrium between wave force and hydrostatic pressure gradient normal to the model boundary and
• at deepest boundary point: set-up is zero.

The shoreline in SWAN moves as dictated by the wave-induced set-up. The set-up computations are available in both the rectilinear and curvilinear grids.