SEQUENTIAL PRESSURE-BASED NAVIER-STOKES ALGORITHMS ON SIMD COMPUTERS: COMPUTATIONAL ISSUES

Abstract Computational issues relevant to parallel efficiency and algorithm scalability are explored on three massively parallel, single-instruction-stream s multiple-data-stream lSIMDr computers, Thinking Machines’ CM-2 and CMS, and MasPar's MP-l, for a two-dimensional semiimplicit sequential pressure-based Navier-Stokes algorithm, by increasing the problem size up to 106 points on a fixed number of processors. On the CMS and MP-I, parallel efficiencies approaching 0.85 are obtained, using a point-Jacobi iterative solver. To obtain peak efficiency, however, the CM-5 requires larger problems than the MP-I, by a factor of 64. To compare with point-Jacobi, a line-Jacobi solver that uses parallel cyclic reduction has also been implemented, and, on the CM-2, the performance in Mflops is consistent with reported results. A uniform approach for boundary coefficient computations is recommended—with separate treatment of interior and boundary control volumes, the run time increases substantially and...