Browsing by Author "Chilakapati, Ashokkumar"

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    A Characteristic-Mixed Method for Contaminant Transport and Miscible Displacement
    (1992-02) Arbogast, Todd; Chilakapati, Ashokkumar; Wheeler, Mary F.
    Recently, Arbogast and Wheeler have formulated and analyzed a modified method of characteristics-mixed method for approximating solutions to convection-diffusion equations. This scheme is theoretically mass conservative over each grid cell; it is approximately so in implementations. We consider application of this procedure to contaminant transport and to miscible displacement with unfavorable mobility ratio. Results in one, two, and three space dimensions are discussed.
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    Three-Dimensional Bioremediation Modeling in Heterogeneous Porous Media
    (1992-04) Wheeler, M.F.; Roberson, K.R.; Chilakapati, Ashokkumar
    Recently Rice University and Pacific Northwest Laboratory (PNL) have begun a collaborative research effort that involves laboratory, field, and simulation work directed toward validating remediation strategies, including both natural and in situ bioremediation at U.S. Department of Energy (DOE) sites such as Hanford. Because of chemical, biological, geologic and physical complexities of modeling these DOE sites, one of the major simulation goals of the project is to formulate and implement accurate and efficient (parallel) algorithms for modeling multiphase/multicomponent flow and reactive transport. In this paper we first describe the physical problem that needs to be modeled. Because of the emergence of concurrent supercomputing, we propose accurate numerical algorithms that are based on operator-splitting in time and domain decomposition iterative techniques. In particular, three characteristic finite element methods and two operator-splitting algorithms are described for advection-diffusion-reaction problems. Three-dimensional bioremediation modeling results in a heterogeneous saturated porous medium are presented.