Techniques for composed and refined grid implementations

John C. Warner, USGS, Woods Hole, MA
Hernan Arango, Rutgers University, NJ

The capabilities of structured grid models to resolve flow dynamics can be limited due to the rectilinear connectivity of the grid. The rectilinear grid may have difficulties to resolve fine spatial scales in regions of strongly varying connections or along coastal features. Methods to allow increased flexibility include grid curvature, land/sea masking, and grid stretching. However these techniques can be inadequate to provide increased resolution for many numerical investigations.

Here we describe methodology to increase the capabilities of structured grid models to allow increased grid flexibility and grid resolution. We describe a method of composed grids that allow an unlimited number of grids to be seamlessly connected. The formulation allows increased grid flexibility that can be used to resolve strongly varying geometric configurations. Additionally, we describe a method for grid refinement that maintains the dynamics of the numerical algorithms and allows two-way feedback between a region of increased resolution and the coarser parent grid. Examples of both methods are shown for idealized test cases and for realistic applications.