Boundary conditions

The boundaries of the computational grid in SWASH are either land, beach or water. SWASH provides the following specification of boundary conditions:

- different wavemakers:
- Regular waves by means of Fourier series or time series.
- Irregular unidirectional waves by means of 1D spectrum. The spectrum may be obtained from observations or by specifying a parametric shape (Pierson-Moskowitz, Jonswap or TMA).
- Irregular multidirectional waves by means of 2D spectrum. The spectrum may be obtained from a SWAN run or by specifying a parametric shape (Pierson-Moskowitz, Jonswap or TMA) while the directional spreading can be expressed with the well-known cosine power or in terms of the directional standard deviation.

- absorbing-generating boundary conditions,
- velocity or discharge,
- Riemann invariants,
- full reflection at closed boundaries or solid walls,
- Sommerfeld or radiation condition,
- sponge layers, and
- periodic boundary conditions.

SWASH has the option to make a computation that is nested in SWAN. In such a run, SWASH interpolates the locations, as specified in the SWAN run with