The 2015 AMMCS-CAIMS Congress

Interdisciplinary AMMCS Conference Series

Waterloo, Ontario, Canada | June 7-12, 2015

AMMCS-CAIMS 2015 Plenary Talk

DNS/LES of Complex Turbulent Flows beyond Petascale

Paul Fischer (University of Illinois)

Petascale computing platforms currently feature million-way parallelism and it is anticipated that exascale computers with billion-way concurrency will be deployed in the early 2020s. In this talk, we explore the potential of computing at these scales with a focus on turbulent fluid flow and heat transfer in a variety of applications including nuclear energy, combustion, oceanography, vascular flows, and astrophysics. Following Kreiss and Oliger ’72, we argue that high-order methods are essential for scalable simulation of transport phenomena. We demonstrate that these methods can be realized at costs equivalent to those of low-order methods having the same number of gridpoints. We further show that, with care, efficient multilevel solvers having bounded iteration counts will scale to billion-way concurrency. Using data from leading-edge platforms over the past 25 years, we analyze the scalability of state-of-the-art solvers to predict parallel performance on exascale architectures. The analysis sheds light on the expected scope of exascale physics simulations and provides insight to design requirements for future algorithms, codes, and architectures.
Paul Fischer is a Blue Waters Professor at the University of Illinois, Urbana-Champaign in the departments of Computer Science and Mechanical Science & Engineering. He received his Ph.D. in mechanical engineering from MIT and was a post-doc in applied mathematics at Caltech, where he was the first Center for Research in Parallel Computation fellow. His work is in the area of high-order numerical methods for partial differential equations, scalable linear solvers, and high-performance computing. He is the architect of the open source SEM-based fluid dynamics/heat transfer code Nek5000, which has been recognized with the Gordon Bell Prize in high-performance computing and which has successfully scaled beyond a million processes. Nek5000 is currently used by over 200 researchers for a variety of applications in turbulence and heat transfer.