The format of the initial concentration (in component unit) for the state variable can be specified as
· Constant (in domain)
· Varying in domain
For the case with varying in domain you have to prepare a data file containing the concentration (in component unit) before you set up the hydrodynamic simulation.
In case of 2D simulation the file must be a 2D unstructured data file (dfsu) or a 2D grid data file (dfs2).
In case of 3D simulation the file depends on the state variable. If the state variable is defined as 2D, the file must be a 2D unstructured data file (dfsu) or a 2D grid data file (dfs2). If the state variable is defined as 3D, the file must be a 3D unstructured data file (dfsu) or a 3D grid data file (dfs3).
The area in the data file must cover the model area. If a 2D dfsu-file is used, a piecewice constant interpolation is used to map the data. If a 3D dfsu-file is used the mesh in the data file must match exactly the mesh in the simulation. If a dfs2-file or a dfs3-file is used, a bilinear interpolation is used to map the data. In case the input data file contains a single time step, this field is used. In case the file contains several time steps, e.g. from the results of a previous simulation, the actual starting time of the simulation is used to interpolate the field in time. Therefore the starting time must be between the start and end time of the file.