Forschungen und Berichte zur Mathematik

A Multiply Nested Model for Non-Linear Shallow Water Model

Huda Altaie

The principle objective of this paper is to study the accuracy and efficiency of two-way performance nesting techniques for structured grids between a coarse grid and a fine grid for 2D shallow water models using explicit finite difference scheme. This model consists of a higher- resolution (fine grid) model with nested 3:1 embedded in a low-resolution (coarse grid) model on which covers the entire domain. The formulation of the mesh nesting algorithm of the structure grid model allows flexibility in deciding the number of meshes and the ratio of grid resolution between adjacent meshes. The two- way nesting is satisfied with an interpolating of the coarse grid domain to provide boundary conditions for the fine grid region and by updating the variables on the fine grid is suit- ably averaged onto the coarse grid in order to drive the coarse grid model. Comparing the results of a fine grid and a coarse grid shows the two- way nesting technique to be working efficiently over different periods of time and these results indicate good performance of the nesting technique.