Two-dimensional, unstructured mesh generation for tidal models

The successful implementation of a finite element model for computing shall ow-water flow requires the identification and spatial discretization of a s urface water region. Since no robust criterion or node spacing routine exis ts, which incorporates physical characteristics and subsequent responses in to the mesh generation process, modelers are left to rely on crude gridding criteria as well as their knowledge of particular domains and their intuit ion. Two separate methods to generate a finite element mesh are compared fo r the Gulf of Mexico. A wavelength-based criterion and an alternative appro ach, which employs a localized truncation error analysis (LTEA), are presen ted. Both meshes have roughly the same number of nodes, although the distri bution of these nodes is very different. Two-dimensional depth-averaged sim ulations of now using a linearized form of the generalized wave continuity equation and momentum equations are performed with the LTEA-based mesh and the wavelength-to-gridsize ratio mesh. All simulations are forced with a si ngle tidal constituent, M-2. Use of the LTEA-based procedure is shown to pr oduce a superior (i.e., less error) two-dimensional grid because the physic s of shallow-water flow, as represented by discrete equations, are incorpor ated into the mesh generation process. Copyright (C) 2001 John Wiley & Sons , Ltd.