Randall J. McDermott
Fire Research Division
Engineering Laboratory
National Institute of Standards and Technology (NIST)
Gaithersburg, Maryland
Thursday, February 26, 2015
2:00pm
800 22nd Street NW, SEH B1270
Washington, DC 20052
Hosted by: Dr. Ilias Balaras ([email protected])
In this talk, a strategy is proposed to guarantee realizability of species mass fractions in an explicit solution of the PDEs governing fire dynamics. The numerical difficulties inherent in the background species approach are discussed and the potential for realizability violations is illustrated. To guarantee realizability the mass density must remain positive (semidefinite). A scalar boundedness correction is proposed that is based on a minimal diffusion operator. The overall scheme is implemented in a publicly available large-eddy simulation code called the Fire Dynamics Simulator (FDS). A set of test cases is presented to verify that the new strategy (1) maintains realizability, (2) does not generate spurious mass, and (3) maintains second-order accuracy for transport. We also provide a brief background in fire modeling and an overview of the FDS flow solver.
Randy McDermott joined the Fire Research Division at NIST in 2008. He received a B.S. from the University of Tulsa in Chemical Engineering in 1994 and a Ph.D. in Chemical Engineering from the University of Utah in 2005. He did his post-doctoral research in Mechanical Engineering at Cornell developing filtered-density function methods. His research interests include subgrid-scale models and numerical methods for large-eddy simulation, adaptive mesh refinement, immersed boundary methods, and Lagrangian particle methods.