Grid generation - Examples

Coastal section of North Holland

Svašek Hydraulics was asked to model the effects of several alternatives to protect the coast of North Holland (The Netherlands) To speed up the building of the model an existing unstructured grid of the Southern part of the North Sea was taken and refined near the coast of North Holland to a grid size of 15 metres. In this way no complicating nesting techniques are necessary. The computational time of such a large grid is still acceptable, since most of the triangles (about 90%) are located in the area of interest. A grid size of 15m near the coast is necessary to take into account the effect of wave breaking and longshore sand transport.

The animation below shows the computational grid which is used in this study. The figures zooms into the area of interest which has a grid size of 15m, while the triangles at the boundaries have a grid size of approximately 8000m.

Computational grid "North Holland" (In color: height of each gridcel in metres above MSL).

Basically the smallest triangle in the grid controls the time step of the model. The automatic time step in the model guarantees numeric stability.