Professeur à l’Université de Lorraine - Mines Nancy / Chercheur au Lemta
Abstract : The classical RANS turbulence models for CFD are, for the ones most used in engineering studies, eddy viscosity models like the "k − e" or "k − ω" models. However, these models have flaws, not only regarding the eddy-viscosity assumption. Based on the channel flow DNS database of Lee & Moser 2015, I will confirm for both models the relevance of the k equation but also the flaws of the highly heuristical e or ω equations, and display "wall damping problems". I will also advocate the νt model of Spalart & Allmaras, and the "k − νt" models of Menter et al. Interestingly, these latter models, also named ‘Scale - Adaptive’ (SA), are claimed to be ‘instability sensitive’, in that they may run in hybrid RANS-LES mode.
I will then present briefly the high Reynolds number analytic theory of Stefan Heinz 2019 for some mean fields of ‘turbulent wall flows’: zero - pressure gradient boundary layer, channel and pipe flows.