The NWT (Numerical Wind Tunnel) computer system available at the NAL (National Aerospace Laboratory) since February 1993 comprises two system administrators, n processing elements (where n was 140 at the beginning, and is 166 at present) and a crossbar network, and operates as a distributed-memory message-passing MIMD (Multiple Instruction and Multiple Data stream) computer. Each processing element itself is a vector computer. This paper reports parallel computations of incompressible viscous flow in a lid-driven square cavity on the NWT computer system. In order to obtain numerical solutions of this flow, consistent finite-difference approximations on nonstaggered grids and four iterative solution methods are used. Computations are performed on the Reynolds number range of Re = 0 to 10(exp 5), and effects of the Reynolds number, number of processing elements (pe) in the parallel processing, solution method and grid size on the computational results are examined. Actual rates of the parallelized square cavity programs on the NWT computer system are measured, and two characteristic parameters of these programs are estimated for the cases that the actual rate is considered as a function of pe and that the actual rate is considered as a function of the grid size. Measurements of the maximum actual rate and estimations of the speedup and efficiency against pe on the NWT computer system are indicated as well.
Parallel computations of incompressible viscous flow in a lid-driven square cavity and program performance on the NWT computer system
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