One-way spatial multiscale method for optimal bioremediation design

Ground-water management models can be computationally intensive and field-scale application of these techniques to complex processes such as in situ bioremediation is not currently possible. A one-way spatial multiscale methodology is investigated for reducing computational effort associated with solving a ground-water management model. The multiscale approach reduces the computational burden by solving the model on a coarse mesh and then using the coarse mesh solution as a starting point for successively finer meshes, proceeding "one-way" from coarse to fine meshes. The performance of the method is presented for two different cases with different dispersivities using a three-level multiscale approach. Over 50% reduction in computing time was achieved in both cases. For the case with low dispersivity, convergence difficulties were encountered on the coarsest mesh that were overcome by using a higher dispersivity on the coarsest mesh and then switching back to the desired low dispersivity on the finer meshes. The choice of penalty weights for constraint violations also proved to be critical to the performance of this approach. Guidelines for selecting appropriate penalty weights are given.