Preprocess static subdomain decomposition in practical cases of 2D unsteady hydraulic simulation

Explicit finite volume methods are frequently used and widely accepted in hydraulic models based on the shallow water approximation. The main drawback of the approach is the time step size limit imposed by the Courant–Friedrichs–Lewy numerical stability constraint. This leads to excessively long computational times in large scale cases of practical interest. At the same time, the accuracy of the numerical results is associated to the use of fine computational meshes able to achieve enough spatial resolution. Taking into account that hydraulic modelers do not have access, in general, to large computational facilities, suitable and useful parallelization techniques are required. Furthermore, if high performance computing facilities are used, it is usually necessary to provide an estimation of the requirements of computational load to cover the length of the simulation. In this work the suitability of a preprocess static subdomain decomposition is explored and presented as a promising strategy to improve the efficiency of 2D unsteady shallow water computational models over dry bed in medium scale computational facilities and, at the same time, is useful to provide a preprocess computational time estimation if large scale computational facilities are going to be used.