Accession Number : ADA306484

Title :   Long-Range Lattice-Gas Simulation on the CAM-8 Prototype.

Descriptive Note : Final rept.,

Corporate Author : PHILLIPS LAB HANSCOM AFB MA

Personal Author(s) : Yepez, Jeffrey

PDF Url : ADA306484

Report Date : 21 SEP 1995

Pagination or Media Count : 50

Abstract : A novel algorithmic method presented for simulating complex fluids, for instance multiphase single component fluids and molecular systems. The algorithm falls under a class of single-instruction multiple-data computation known as lattice-gases, and therefore inherits exact computability on a discrete spacetime lattice. Our contribution is the use of nonlocal interactions that allow us to model a richer set of physical dynamics, such as crystallization processes, yet to do so in a way that remains locally computed. A simple computational scheme is employed that allows all the dynamics to be computed in parallel with two additional bits of local site data, for outgoing and incoming messengers regardless of the number of long-range neighbors. The computational scheme is an efficient decomposition of a lattice-gas with many neighbors. It is conceptually similar to the idea of virtual intermediate particle momentum exchanges that is well known in particle physics. All 2-body interactions along a particular direction define a spatial partition that is updated in parallel. Random permutation through the partitions is sufficient to recover the necessary isotropy as long as enough momentum exchange directions are used. The algorithm is implemented on the CAM-8 prototype.

Descriptors :   *PARALLEL PROCESSING, *MOLECULE MOLECULE INTERACTIONS, MATHEMATICAL MODELS, ALGORITHMS, COMPUTERIZED SIMULATION, SPATIAL DISTRIBUTION, MICROSTRUCTURE, OPTIMIZATION, DATA MANAGEMENT, TIME DEPENDENCE, CRYSTAL LATTICES, EFFICIENCY, INPUT OUTPUT PROCESSING, PROTOTYPES, CRYSTALLIZATION, VAPOR PHASES, GAS DYNAMICS, LIQUID PHASES, MOLECULAR STRUCTURE, TWO PHOTON ABSORPTION, NAVIER STOKES EQUATIONS, BOLTZMANN EQUATION, N BODY PROBLEM, PARTICLE COLLISIONS, MOMENTUM TRANSFER, AUTOMATA, SYMMETRY(CRYSTALLOGRAPHY), MULTIPHASE FLOW.

Subject Categories : Computer Programming and Software
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE