摘要 :
The need for high speed processing is briefly outlined, and some related areas of research are described. The areas covered are: parallel processing configurations based on microprocessors, the simulation of these systems to inves...
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The need for high speed processing is briefly outlined, and some related areas of research are described. The areas covered are: parallel processing configurations based on microprocessors, the simulation of these systems to investigate effectiveness and implementation details, and application to the solution of control algorithms.
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Our research activity in edge plasma modeling is directed towards understanding edge plasma behavior and towards innovative solutions for controlling the edge plasma as well as the design and operation of impurity control, particl...
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Our research activity in edge plasma modeling is directed towards understanding edge plasma behavior and towards innovative solutions for controlling the edge plasma as well as the design and operation of impurity control, particle exhaust. and plasma facing components. During the last nine months, substantial progress was made in many areas. The highlights are: (A) Development of a second-generation edge-plasma simulation code (Section II); (B) Development of models for gas-target divertors, including a 1(1/2)-D fluid model for plasma and Monte Carlo neutral-transport simulations (Section III); and (C) Utilization of the RF ponderomotive force and electrostatic biasing to distribute the heat load on a larger area of the divertor plate, and the development of analytical and numerical transport models that include both ponderomotive and electrostatic potentials.
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PROMISE is a computer-based, general simulation tool for studying systems consisting of concurrent processes exchanging discrete signals that influence these processes. Because of its general set-up, it can be applied to simulatio...
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PROMISE is a computer-based, general simulation tool for studying systems consisting of concurrent processes exchanging discrete signals that influence these processes. Because of its general set-up, it can be applied to simulation of a variety of discrete systems. Through the modular approach of its set-up, models and submodels of the simulated system can be easily substituted for other (sub) models - if necessary more detailed - without affecting the general structure of the simulator. This enables not only fast and effective parameter studies, but also versatile detailed studies of various relevant aspects.
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This paper discusses research efforts at the Naval Research Laboratory (NRL) in the area of environmentally adaptive navigation and dynamic mission planning. Presented in this paper is the system architecture being developed for t...
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This paper discusses research efforts at the Naval Research Laboratory (NRL) in the area of environmentally adaptive navigation and dynamic mission planning. Presented in this paper is the system architecture being developed for the accomplishment of objective based dynamic navigation. A simulator is being constructed that incorporates this architecture and its design is presented. This simulator will enable the future development of specific mission behavior modules.
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Virtual memory computers are capable of executing large-scale particle simulations even when the memory requirements exceed the computer core size. The required address space is automatically mapped onto slow disc memory by the op...
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Virtual memory computers are capable of executing large-scale particle simulations even when the memory requirements exceed the computer core size. The required address space is automatically mapped onto slow disc memory by the operating system. When the simulation size is very large, frequent random accesses to slow memory occur during the charge accumulation and particle pushing processes. Accesses to slow memory significantly reduce the execution rate of the simulation. We demonstrate in this paper that with the proper choice of sorting algorithm, a nominal amount of sorting to keep physically adjacent particles near particles with neighboring array indices can reduce random access to slow memory, increase the efficiency of the I/O system, and hence, reduce the required computing time. (ERA citation 07:063785)
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For plumes originating in urban areas, the larger-scale transport may depend onthe near-source dispersal patterns within the city. In addition, the near-source dispersal behavior within the urban canopy may depend on the larger-sc...
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For plumes originating in urban areas, the larger-scale transport may depend onthe near-source dispersal patterns within the city. In addition, the near-source dispersal behavior within the urban canopy may depend on the larger-scale flow features. In this paper, we will present preliminary meteorological and tracer dispersion simulations from a hierarchy of three prognostic models that were centered around Salt Lake City, Utah. The mesoscale COAMPS, the urban-scale HIGRAD, and the building-scale FEM3MP models were used to perform the simulations in a nested configuration. The multi-scale modeling approach allows us to explicitly capture mesoscale flow features over the large domain as well the effects of individual buildings in the smaller area of interest. At the conference, we will discuss an early morning and an afternoon simulation case and evaluate the effects of stability on transport and dispersion on the urban and building scales. We also will study whether or not the dispersion over the mesoscale is sensitive to what happens on the building scale.
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Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and/or dispersion. Additionally during the transpo...
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Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and/or dispersion. Additionally during the transport of parent and daughter radionuclides in soil, radionuclide decay may occur. This version of CASCADER called CASCADR9 starts with the concepts presented in volumes one and three of this series. For a proper understanding of how the model works, the reader should read volume one first. Also presented in this volume is a set of realistic scenarios for buried sources of radon gas, and the input and output file structure for CASCADER9. (ERA citation 19:011799)
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Advanced mathematical techniques and computer simulation play a major role in providing enhanced understanding of conventional materials processing operations such as welding and joining. Many of these numerical models are highly ...
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Advanced mathematical techniques and computer simulation play a major role in providing enhanced understanding of conventional materials processing operations such as welding and joining. Many of these numerical models are highly compute-intensive. It is not unusual for an analysis to require several hours of computational time on current supercomputers despite the simplicity of the models being studied. As computer simulations and materials databases grow in complexity, massively parallel computers have become important tools. This paper briefly describes massively parallel computational research at the ORNL with the objective of providing fundamental insight into the welding process.
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