Adaptive unstructured mesh generation methods for hydrogeological problems

Two mesh generators embedded in the GeRa code for the solution of groundwater flow and radionuclide transport problems are discussed. The first one is a triangular-prismatic generator with the ability of cell degeneration; the second one is the polyhedral octree mesh generator implementing the cut-cell technology. These generators allow the user to automatically create conformal polyhedral adaptive grids in three-dimensional geological domains with consideration of complex boundaries, top and bottom geological layer surfaces, pinch-outs, and geological heterogeneities.