A sensitivity study of numerical solutions of the South China Sea ocean model to various grids generated by grid generation technique

Abstract

The sensitivity of numerical solutions of systems of nonlinear flow equations (Navier-Stokes equations) to the grid used is investigated through the use of the South China Sea (SCS) numerical ocean model. Traditionally, rectangular coordinate grids are used in environmental modeling. The advantage of rectangular coordinate grids is their simplicity in the generation process. However, rectangular coordinate grids are not well suited for regions with complex terrain (coastlines and topography) and occasionally lead to poor accuracy in numerical solutions. The grid generation techniques are being introduced to coastal ocean modeling to study the sensitivity of numerical solutions to the grid used and to investigate the enhancement of the modeling process. Grid generation techniques are broadly used in aeronautical engineering community for solving CFD problems. One orthogonal (l2lxl9l) and two curvilinear nearly-orthogonal grids (l2lxl9l and lSlx24l) are designed to couple with the SCS numerical ocean model. The grids are designed using the EAGLEView grid generation code developed by the National Science Foundation (NSF) Engineering Research Center (ERC) of Mississippi State University. EAGLEView implements a grid generation technique using mainly elliptic and algebraic generation systems. The designed grids are processed with the SOS numerical ocean model for 200 days to study the sensitivity of numerical solutions to the grid used. The solutions of the temperature and salinity fields are presented and analyzed. The advantages of curvilinear nearly- orthogonal grids are also discussed. (MM)