A Simulation on homogeneous isotropic turbulent flows on the earth simulator

Yokokawa, Mitsuo; Saito, Minoru*; Ishihara, Takashi*; Kaneda, Yukio*

With the advent of supercomputers, large-scale direct numerical simulations(DNS) of the Navier-Stokes equations are possible to carry out. However, larger scale DNS is required to make turbulence clear and to make a parameterization of turbulence. The Earth Simulator is a distributed memory parallel supercomputer whose peak speed is 40 Tflop/s and it is very useful to make a very large-scale DNS. Simulation codes named have been developed for the Earth Simulator and their correctness have been validated by compareing the simulation results by with ones by a conventinal code. The sustatined performance of 3.72Gflop/s is obtained in the execution of the serial version with the problem size of on an arithmetic processor(AP) of the Earth Simulator. Speedup of about 7 is achieved in 8APs by the parallelized code. Sppedup is degraded by the execution of 8 processor nodes, however, efficiency of 25% against the peak performance is obtained for the problem size of .