Mark A. Christon

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The application of discrete solution methods to the second-order wave equation can yield a dispersive representation of the non-dispersive wave propagation problem resulting in a phase speed that depends not only upon the wavelength of the signal being propagated but also upon the direction of propagation. In this work, the dependence of the dispersive(More)
Approved for public release; further dissemination unlimited. States Government. Neither the United States Government, nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees, make any warranty, express or implied, or assume any legal liability or responsibility for the accuracy, completeness, or(More)
This paper discusses the design and implementation of solution algorithms suitable for performing transient, incompressible viscous ow simulations on massively parallel computers. The nite element formulation for incompressible ow along with the ad-hoc modiications for explicit time integration are discussed with an emphasis on implementation aspects for(More)
A two-pass surface extraction algorithm for adaptive finite element meshes is presented in the context of a visualization study for a particle impact and a turbine blade containment problem. The direct use of finite element data structures for the computation of external surfaces, surface normals, and derived physical quantities is discussed. An overview of(More)
Approved for public release; distribution is unlimited. Laboratory strongly supports academic freedom and a researcher's right to publish; as an institution, however, the Laboratory does not endorse the viewpoint of a publication or guarantee its technical correctness. Actinide separation is important for fuel reprocessing in the nuclear energy industry,(More)
The research summarized in this paper is part of a multi-year effort focused on evaluating the viability of wavelet bases for the solution of partial diierential equations. The primary objective for this work has been to establish a foundation for hierarchical/wavelet simulation methods based upon numerical performance, computational eeciency, and the(More)
Approved for public release; further dissemination unlimited. States Government. Neither the United States Government, nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees, make any warranty, express or implied, or assume any legal liability or responsibility for the accuracy, completeness, or(More)
Two alternative approaches to the solution of discrete ordinate transport are considered in the context of general unstructured grids. The more traditional approach considered is the solution of a lower triangular system of equations for the spatial intensity distribution. Alternatively, the iterative solution of the system of equations arising from a more(More)