Direkte numerische Simulation turbulenter Stroemungen auf Parallelrechnern

The parallelization of the program DISTUF for direct numerical simulation of a homogeneously turbulent and stratified shear flow is described. A new parallel three-dimensional Poisson solver is introduced. The portable implementation of the program using the message-passing standard MPI on parallel computers with shared or distributed memory is presented. The comparison of runtimes, speed-ups and efficiencies on leading parallel computersystems in Europa leads to a performance benchmark of all relevant sysems in high performance computing. Results from simulation runs with up 480"3 gridpoints on a 48 nodes IBM SP2 are presented. These simulations resolve the universal inertial range of the turbulence energy spectra for the first time. Furthermore, new findings on the value of the critical Richardson number and its dependence on the shear number and the Reynolds number of the flow are shown. (orig.)43 figs., 8 tabs., 85 refs.Available from TIB Hannover: RN 437(97-04) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman