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Introduction

Both spatial grids and time windows need to be defined.


The spatial grids that need to be defined by the user are (if required):

Wind, bottom friction, grain sizes, heights of porous structures and vegetation density do not require a grid if they are uniform over the area of interest.


For one-dimensional situations, i.e. $ \partial$/$ \partial$y $ \equiv$ 0, SWASH can be run in 1D mode.


If a uniform, rectangular computational grid is chosen in SWASH, then all input and output grids must be uniform and rectangular too, but they may all be different from each other.


If an orthogonal curvilinear computational grid is chosen in SWASH, then each input grid should be either uniform, rectangular or identical to the used curvilinear computational grid.


Also, SWASH may operate with different time windows with different time steps (each may have a different start and end time and time step): During the computation SWASH obtains bottom, current, water level, wind, pressure, bottom friction, porosity, grain size, structure height and vegetation density information by tri-linear interpolation from the given input grid(s) and time window(s). The output is in turn obtained in SWASH by bi-linear interpolation in space from the computational grid; there is no interpolation in time, the output time is shifted to the nearest computational time level. Interpolation errors can be reduced by taking the grids and windows as much as equal to one another as possible (preferably identical). It is recommended to choose output times such that they coincide with computational time levels.


next up previous index
Next: Computational grid and time Up: Choice of grids and Previous: Choice of grids and   Index
The SWASH team 2017-04-06