SMS:Telescoping Grids

One of the most restrictive attributes of a Cartesian grid is the limited variability in resolution. By the purest definition, a Cartesian grid consists of square cells, meaning a constant resolution over the entire domain. A method that can be employed to support variable resolution involves the creation/use of what can be called a Telescoping Grid (sometimes referred to as a Quad Tree). The CMS-Flow model is the only numeric engine currently supported by the SMS which allows computation on a telescoping grid.

The generation of a telescoping grid involves:

• A base grid
• Refinement features

To generate a telesIn this approach, a base grid with constant cell size (rectangular or square cells) serves as the background resolution. This base grid is the first parameter for generation of CMS-Flow can use a grid with varying resolution which is referred to as a telescoping grid. Telescoping grids have a base grid with a specified cell size. The cells in the child grid of the base grid have half the cell size (half in both I and J directions). This means each cell is divided into 4 cells.

Telescoping grids are created by creating polygons where the user wants the different levels of refinement in a CMS-Flow coverage. Each polygon is assigned the maximum allowable size for cells in this area. When using Map→2D Grid, specify the size of the base grid. SMS will build a telescoping grid with as many levels as required to satisfy the constraints imposed by the polygons.

Note: Telescoping grids in SMS 11.0 are introduced with limited capability and no support. There are known issues such as problems with shading that will not be addressed in SMS 11.0.