The format of the eddy viscosity coefficient, or the Smagorinsky coefficient, can be specified as
· Constant (in domain)
· Varying in domain
For the case with values varying in domain the values vary in the horizontal domain only. In case of a 3D simulation the values are constant in the vertical domain.
For the case with values varying in domain you have to prepare a data file containing the eddy viscosity coefficient or the Smagorinsky coefficient before you set up the hydrodynamic simulation. The file must be a 2D unstructured data file (dfsu) or a 2D grid data file (dfs2). The area in the data file must cover the model area. If a dfsu-file is used piecewice constant interpolation is used to map the data. If a dfs2-file is used bilinear interpolation is used to map the data.