Dr Philippe Spalart studied Mathematics and Engineering in Paris, and obtained an Aerospace PhD at Stanford/NASA-Ames in 1982. Still at Ames, he conducted Direct Numerical Simulations of transitional and turbulent boundary layers. Moving to Boeing in 1990, he created the Spalart-Allmaras one-equation Reynolds-Averaged Navier-Stokes turbulence model. He wrote a review 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. He received the AIAA Fluid Dynamics Award in 2006, became a Boeing Senior Technical Fellow in 2007, was elected to the National Academy of Engineering in 2017, and had the AIAA Reed Award for 2019. His papers have been cited 54,000 times. Recent work includes refinements to the SA model and DES, computational aeroacoustics, theories for aerodynamics and turbulence, and the design of research experiments. Philippe retired from Boeing in 2020.
Abstract
The persistent need to assess and improve RANS models, in this era of Turbulence-Resolving Simulations, is justified. The tendency to stagnation is partly explained by factors such as: the sheer scope of the project, given minimal tools and all the constraints of CFD solvers; the disappointing contribution of DNS; a newly argued Structural Limitation for “classical” RANS models; the lack of maturity in AI work; and the surprising prevalence of what are to the author obvious Fallacies. The user-adjustable models GEKO and SG26 are discussed. On a more positive note, the integration with experiment and DNS is now stronger thanks to modern flow-field measurements and creative quantities extracted from DNS.
