2D Grid Element
A 2D surface is modeled with a 2D Grid Element. Currently, only one Active Grid (2D Grid Element) (see also: Surface Definition Alternative) can be computed with a simulation run. The 2D Grid Element includes the physical dimensions of the 2D computational grid cells that will be generated, then computed as part of a coupled 1D-2D hydrodynamic model. The generated computational area is composed of square grid cells that calculate two-dimensional flow across the surface.
To preview the resulting 2D computational grid cells, right click on the 2D Grid Element and select Grid Browser. The 2D cells are assigned their ground elevations (at their grid cell centers) from the active terrain model. Alternatively, launch the 2D Grid Browser window to review the various 2D Grid Data Layers that are derived from processing of 2D Grid Adjustment Elements atop the 2D Grid Element.
- Grid Cell Size: Enter the desired width of each square-shaped grid cell.
- Angle: Lets you rotate the grid between 90 and –90 degrees, perhaps to better align with a boundary between 1D and 2D subareas in your model.
- Manning’s n (Default): The default user defined value for Manning’s n that be assigned to each grid cell.
- Grid Infiltration Mode: The governing surface infiltration mechanism throughout 2D computational grid. Select <None> if no infiltration losses are to be modeled at all in the 2D grid.
- SCS CN (Default): The SCS CN value assigned to each grid cell, unless overriden by a value with an overlapping 2D Grid Adjustment Layer or 2D Grid Adjustment Element. Applicable with the SCS CN infiltration Mode.
- Impermeability Fraction (Default): The value between 0 and 1 that is assigned by default to each grid cell. Applicable with the SCS CN infiltration Mode.