Time-reversibility of Navier-Stokes turbulence and its implication for subgrid-scale models

The last two decades have seen the emergence of a large number of new subgrid models, and it is the authors’ opinion that the turbulence community must devote more efforts in developing consensual criteria than in increasing the number of models. The purpose of the present letter is to investigate one possible criterion, which is the time-reversibility of a subgrid model, when the sign of the velocity is inverse, i.e., under the transformation u→−u. We report the results of Eddy-Damping Quasi-Normal (EDQN) simulations in which the velocity is reversed in all, or part, of the scales of the flow. These results are then compared to results from LES in which the velocity is reversed, to assess the quality of the predictions of the models and to check whether time-reversibility is a valid criterion to assess subgrid models.