Jackie Hallberg

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Kavanagh, Kathleen Rose. Nonsmooth Nonlinearities in Applications From Hydrology. (Under the direction of C.T. Kelley) This work has two parts; simulation of unsaturated flow and optimization of remediation problems. For the unsaturated flow simulation, we propose an adaptive time stepping scheme based on error control for Richards’ equation, a model for(More)
Richards' equation is a model for ow in the unsaturated zone. Adaptive implicit methods for temporal integration of Richards' equation have been used with considerable success. The nonlinearities in the van Geneuchten and Mualem formulae that are often used to close the system can be nonsmooth and even non-Lipschitz. This lack of smoothness means that the(More)
A grid re nement scheme has been developed for tetrahedral and triangular grid-based calculations in message-passing environments. The element adaption scheme is based on edge bisection of elements marked for re nement by an appropriate error indicator. Hash table/linked list data structures are used to store nodal and element information. The grid along(More)
In this paper we discuss the design and implementation of a Newton-Krylov-Schwarz solver for the implicit temporal integration on an unstructured three-dimensional spatial mesh of Richards’ equation for groundwater flow in unsaturated porous media. We use aggregation techniques from the algebraic multigrid literature to construct a coarse mesh for two-level(More)
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