Experiences from Leadership Computing in Simulations of Turbulent Fluid Flows

We performed a direct numerical simulation (DNS) of high Reynolds number turbulent channel flow to expand our understanding of wall-bounded turbulence. The resolution requirements inherent to realistic turbulent flows necessitate leadership computing systems. Using Mira at Argonne Leadership Computing Facility, Argonne National Laboratory, we were able to achieve DNS at Re_tau = 5,200, and generated approximately 140 Tbytes of data. To use Mira efficiently, we developed a new DNS code, PoongBack, including a new parallel 3D FFT kernel. The new code shows excellent scalability up to 786,432 cores. Here, we summarize our code development and production simulation efforts, including parallel I/O.