Development of stochastic models for turbulence

Abstract

Subgrid scale interactions in forced homogeneous turbulence are decomposed into components correlated and uncorrelated with the resolved velocity field. The correlated part is well known to be equivalent to a spectral eddy viscosity. The mean energy transfer can be predicted even if the uncorrelated remainder is ignored, but statistics pertaining to the fluctuations of the nonlinear term require a model for the remainder, which is found to have a strongly non-Gaussian probability density. Some implications of including these non-Gaussian properties in stochastic models are described. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.