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Unformatted text preview: random aquifer simulations. Convergence of both inner iterations (CG) and outer iterations (Picard) were carefully controlled via stopping criteria and a posteriori analyses of convergence rates. We found that double precision computations were necessary for highly heterogeneous permeabilities. Finally, in order to overcome convergence problems due to large K contrasts (σlnK>>1), we introduced a σ-continuation method (homotopy). The continuation method and other procedures developed in this paper are aimed at a better understanding of σZSALT(x), i.e., the variability of seawater intrusion in highly heterogeneous aquifers. A robust perturbation theory is currently being considered for interpreting the results for σlnK>>1. A previous perturbation theory (Ababou & Al-Bitar 2005) provided a fairly good fit for σlnK up to 1.60. Possibly, the correct interpretation of the present numerical experiments requires, for σlnK>>1, larger sampling domains (10 million nodes) and/or multiple replicates (Monte-Carlo). Other numerical developments include pumping well modelling, and efficient algorithms to deal with irregular 2D and 3D grid geometry for...
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This document was uploaded on 01/19/2014.

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