Solution adaptive methods for low-speed and all-speed flows

The goal of this work was to design new fast algorithms that could be used to solve fluid flows at all speeds by building upon the best approaches now available for solving very low speed flows and high speed flows. Furthermore the algorithms developed must be appropriate for use on complex moving geometries and for use with adaptive mesh refinement. The algorithms must also be extendible to chemically reacting (combustion) flows. To this end they have developed new methods for efficiently computing fluid problems that involve low-speed flows and problems that are a mixture of low-speed and high-speed flows. The algorithms have been implemented in 2D and 3D on moving overlapping grids and will be a fundamental component of the chemically reacting flow solvers that they are now developing for industrial applications

Adaptive rezoner in a two-dimensional Lagrangian hydrodynamic code

In an effort to increase spatial resolution without adding additional meshes, an adaptive mesh was incorporated into a two-dimensional Lagrangian hydrodynamics code along with two-dimensional flux corrected (FCT) remapper. The adaptive mesh automatically generates a mesh based on smoothness and orthogonality, and at the same time also tracks physical conditions of interest by focusing mesh points in regions that exhibit those conditions; this is done by defining a weighting function associated with the physical conditions to be tracked. The FCT remapper calculates the net transportive fluxes based on a weighted average of two fluxes computed by a low-order scheme and a high-order scheme. This averaging procedure produces solutions which are conservative and nondiffusive, and maintains positivity. 10 refs., 12 figs

Adaptive Mesh Refinement Algorithm Development and Dissemination

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to develop and disseminate adaptive mesh refinement (AMR) algorithms for structured and unstructured meshes. Development of ARM algorithms will continue along several directions. These directions include algorithms for parallel architectures, techniques for the solution of partial differential equations on adaptive meshes, mesh generation, and algorithms for nontraditional or generic applications of AMR. Dissemination of AMR algorithms is also a goal of the project. AMR algorithms are perceived as difficult to meld to current algorithms. The authors are developing tools that diminish this perception and allow more computational scientists to use AMR within their own work

Ultrasound Assessment of the Vertebral Level of the Intercristal Line in Pregnancy

(Anesth Analg. 2011;113(3):559–64

Structured adaptive mesh refinement on the connection machine

Adaptive mesh refinement has proven itself to be a useful tool in a large collection of applications. By refining only a small portion of the computational domain, computational savings of up to a factor of 80 in 3 dimensional calculations have been obtained on serial machines. A natural question is, can this algorithm be used on massively parallel machines and still achieve the same efficiencies We have designed a data layout scheme for mapping grid points to processors that preserves locality and minimizes global communication for the CM-200. The effect of the data layout scheme is that at the finest level nearby grid points from adjacent grids in physical space are in adjacent memory locations. Furthermore, coarse grid points are arranged in memory to be near their associated fine grid points. We show applications of the algorithm to inviscid compressible fluid flow in two space dimensions