VERTICAL DISCRETIZATION IN TIDAL FLOW SIMULATIONS

We propose an empirical law for vertical nodal placement in tidal simu lations that depends on a single parameter p. The influence of dimensi onless numbers on the optimal value of p is analysed through a series of numerical experiments for an individual vertical and a single value of p is found to be adequate for all cases. The proposed law can lead to gains in accuracy of over two orders of magnitude relative to a un iform grid and compares favourably with non-uniform grids previously u sed in the literature. In practical applications the most effective us e of this law may require each vertical to have a different number of nodes. Criteria for the distribution of the total number of nodes amon g different verticals are also proposed, based on the concept of equal izing errors across the domain. The usefulness of the overall approach is demonstrated through a two-dimensional laterally averaged applicat ion to a synthetic estuary.