This is part two of a summer series on Department of Energy computational combustion research. Part one looked at the history of computational combustion.
Combustion models bring
turbulence into the mix
Posted August 17, 2009
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Turbulence has confounded physicists for ages. Richard Feynman called turbulence “the most important unsolved problem in classical Newtonian physics.” Werner Heisenberg was once asked if he had any questions for God. He replied, “Why Relativity? And why turbulence?”
Turbulence describes fluid flow dominated by eddies – patches of swirl that can range in size from the tiny vortices around a hummingbird’s wings to a raging hurricane.
Combustion is a particularly perplexing form of turbulence, says George Catalano, a mechanical engineering professor at the State University of New York (SUNY) at Binghamton. “We have no exact mathematical solution to even the simplest of turbulent flows, and combustion represents some of the most complicated turbulent flows,” says Catalano, an expert in fluid mechanics.
It should be no surprise, then, that simulating combustion takes massive computational power, supplied largely through DOE’s INCITE program (Innovative and Novel Computational Impact on Theory and Experiment) – and by any other means necessary. See sidebar.
Jacqueline Chen and Joe Oefelein say their teams at Sandia National Laboratories’ Combustion Research Facility (CRF) in Livermore, Calif., used an unprecedented amount of computer time – 30 million processor hours on Jaguar, a Cray XT computer at Oak Ridge National Laboratory (ORNL) that has been rated the world’s most powerful for open science. With more than 181,000 AMD Opteron processor cores, Jaguar is capable of 1.64 quadrillion mathematical calculations a second.
“CRF’s focus has been on one-of-a-kind flame simulations using one-of-a-kind supercomputers that are not available to the wider research community,” says aerospace engineering professor Suresh Menon, a Sandia collaborator who directs the Georgia Institute of Technology Computational Combustion Laboratory in Atlanta.
