Large Scale Parallel Direct Numerical Simulation of a Separating Turbulent Boundary Layer Flow over a Flat Plate Using NAL Numerical Wind Tunnel

Abstract

Direct numerical simulation(DNS) of fundamental fluid flow simulation using 3-dimensional Navier-Stokes equations is a typical large scale computing which requires high performance computer with vector and parallel processing. In the present paper a turbulent boundary layer flow simulation with strong adverse pressure gradient on a flat plate was made on NAL Numerical Wind Tunnel. Boundary layer subjected to a strong adverse pressure gradient creates a separation bubble followed by a region with small, but positive, skin friction. This flow case contains features that has proven to be difficult to predict with existing turbulence models. The data from present simulation are used for investigation of the scalings near the wall, a crucial concept with respect to turbulence models. The present analysis uses spectral methods and the parallelization was done using MPI(Message-Passing Interface). A good efficiency was obtained in NWT. To compare with other machine performances, previous computations on T3E and SP2 are also shown.