IMPROVING MULTIBANK MEMORY ACCESS PARALLELISM ON SIMT ARCHITECTURES

Memory mapping has traditionally been an important optimization problem for high-performance parallel systems. Today, these issues are increasingly affecting a much wider range of platforms. Several techniques have been presented to solve bank conflicts and reduce memory access latency but none of them turns out to be generally applicable to different application contexts. One of the ambitious goals of this Thesis is to contribute to modelling the problem of the memory mapping in order to find an approach that generalizes on existing conflict-avoiding techniques, supporting a systematic exploration of feasible mapping schemes

Small business innovation research. Abstracts of completed 1987 phase 1 projects

Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

Lattice Boltzmann simulations of multiphase flows

This thesis is a comprehensive account of my experiences implementing the Lattice Boltzmann Method (LBM) for the purpose of simulating multiphase flows relevant to Air Conditioning and Refrigeration Center (ACRC) applications. Other methodologies have been used to simulate multiphase flow including finite volume based Navier-Stokes solvers. These methods have found reasonable success in simulating multiphase flows. LBM was chosen because of its ability to capture multi-fluid physics including phase-change and interfacial dynamics with relative ease. In addition, the LBM algorithm can be easily parallelized. This allows larger problems to be simulated quicker. Among the multiphase LBM algorithms, we have implemented the Shan-Chen method, the He-Chen method, and an extension to the He-Chen method. We carefully document our methodology and discuss relevant kinetic theory and fluid dynamics. We present results for a number of fundamental flow problems including droplet impingement on solid and liquid surfaces as well as multiphase flow in complex micro-channels. In addition, we examine in great detail the problem of axial droplet migration and deformation in a square-duct at moderate Reynolds number. Our results suggest that the LBM algorithm is capable of simulating a wide range of flows and can accurately capture flow physics provided the density ratio among fluid phases is not large. Because ACRC equipment often harbor high density ratio flows, the standard LBM procedures require modification to accommodate higher density ratio problems. We investigate one such modification to the He-Chen algorithm by introducing a pressure Poisson equation (PPE) to reduce density variation related to compressibility effects