Source: Inside HPC | Staff | November 16, 2019

An illustration of intricate flow structures in turbulence from a large simulation performed using 1,024 nodes on Summit. The lower right frame shows a zoom-in view of a high-activity region. Credit: Dave Pugmire and Mike Matheson, Oak Ridge National Laboratory

Researchers at the Georgia Institute of Technology have achieved world record performance on the Summit supercomputer using a new algorithm for turbulence simulation.

Turbulence, the state of disorderly fluid motion, is a scientific puzzle of great complexity. Turbulence permeates many applications in science and engineering, including combustion, pollutant transport, weather forecasting, astrophysics, and more. One of the challenges facing scientists who simulate turbulence lies in the wide range of scales they must capture to accurately understand the phenomenon. These scales can span several orders of magnitude and can be difficult to capture within the constraints of the available computing resources.

High-performance computing can stand up to this challenge when paired with the right scientific code; but simulating turbulent flows at problem sizes beyond the current state of the art requires new thinking in concert with top-of-the-line heterogeneous platforms.

A team led by P. K. Yeung, professor of aerospace engineering and mechanical engineering at the Georgia Institute of Technology, performs direct numerical simulations (DNS) of turbulence using his team’s new code, GPUs for Extreme-Scale Turbulence Simulations (GESTS). DNS can accurately capture the details that arise from a wide range of scales. Earlier this year, the team developed a new algorithm optimized for the IBM AC922 Summit supercomputer at the Oak Ridge Leadership Computing Facility (OLCF). With the new algorithm, the team reached a performance of less than 15 seconds of wall-clock time per time step for more than 6 trillion grid points in space—a new world record surpassing the prior state of the art in the field for the size of the problem.

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