Nesting

The Nesting toolbox allows nesting an already exisiting finer model in a larger model to increase resolution in the area of interest. Differently from domain decomposition the two models can not run in parallel but boundary conditions from the coarser (overall) model need to be generated at first and then provided to the finer model. For more information we refer to the Delft3D-FLOW manual.

The procedure to generate nested boundary conditions consists of few steps:

1. Open the overall model.
2. Using the tool Nesting – 1 a list of monitoring stations in the overall model, needed for the interpolation of the boundary conditions, can be generated. To do that, “Select grid file”, “Select Enc File” (enclosure file), “Select Bnd File” (boundary condition file) of the finer model. “Make observation points” will create a number of observation points (. obs) at the boundary of the nested model. In addition to this, the program generates the nesting administration (.adm), i.e. the link between the boundary support points in the nested model and the monitoring stations in the overall model. Save all to save the so created observation and administration files.
3. Run the overall model with the list of monitoring stations generated by Nesting -1.
4. The actual boundary conditions (* .bct) for the nested model are generated by Nesting -2 using “Select History File” (“*.his”) of the overall model and “Select Admin file” (nesting administration) and then “Run Nesting”. Boundary conditions can be generated for the “Hydrodynamics” and also “Transport” (e,g, salinity).