Turbulence Prediction in CFD: From One-Equation Models to Large-Eddy-Simulation Hybrids
Speaker: Philippe Spalart, The Boeing Company
Presentation
Abstract
The presentation begins with a history of the Spalart-Allmaras one-equation model, at NASA Ames and Boeing. It includes the initial impulse from Lomax and Baldwin, the publication difficulties, a perspective on other one-equation models, and a discussion of the model’s strengths and weaknesses. We then address the roles of RANS and LES, our “allies” in future turbulence treatments. The enduring limitations of each approach, rooted in physics and/or computing cost, are discussed leading to the need for hybrid RANS-LES treatments long into the future in most aerospace, transportation, energy, and atmospheric applications.
Biography
Philippe Spalart studied Mathematics and Engineering in Paris, and obtained an Aerospace Ph.D. at Stanford through NASA Ames Research Center in 1982. While at Ames, he conducted extensive Direct Numerical Simulations of transitional and turbulent boundary layers. After moving to Boeing in 1990, he created the Spalart-Allmaras (SA) one-equation Reynolds-Averaged Navier-Stokes turbulence model. He wrote a review (once described as “discerning and sobering”) and co-holds a patent on airplane trailing vortices. In 1997, he proposed the Detached-Eddy Simulation approach, blending RANS and Large-Eddy Simulation to address separated flows at high Reynolds numbers with a manageable cost. Recent work includes refinements to the SA model, computational aeroacoustics, and theories for aerodynamics and turbulence.