Toward autonomous large eddy simulations of turbulence based on interscale energy transfer among resolved scales

We show how the subgrid-scale (SGS) energy transfer among resolved scales in large eddy simulations (LES) can be used to obtain the total SGS energy transfer for unknown, full velocity field. The total transfer serves then as a physical constraint on several classical spectral SGS models and can be used to obtain and update model constants at each time step in actual LES. The performance of SGS models depends not only on their ability to capture the total SGS dissipation (which is enforced by the method) but also by distribution of the SGS dissipation among scales of motion (which is enforced by a model). Moreover, we show how the SGS transfer wave number distribution itself can be obtained from the evolving LES velocity fields. Information about the total SGS transfer and its wave number distribution, supplemented by a known asymptotic properties of energy flux in the inertial range, allows autonomous LES, i.e., self-contained simulations without use of extraneous SGS models. The method is tested in LES of isotropic turbulence at high Reynolds number where the inertial range dynamics is expected and for lower Reynolds number decaying turbulence under conditions of the classical Comte-Bellot and Corrsin experiments.