Numerical study of small-scale intermittency in three-dimensional turbulence

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Abstract
Intermittency effects, in magnitude comparable to the early Batchelor & Townsend (1949) experiments, are studied for stationary, homogeneous, isotropic turbulence by means of a direct spectral simulation on a 643 lattice. The turbulence is kept stationary by a coupling to modes external to the spectral code that model the straining effects of large scales on smaller ones. The rate of energy input and viscosity are free parameters. The interrelations of intermittency and parametrizations of the large scales are discussed. Small-scale universality and a local cascade are necessary if comprehensive models of the large scales are to prove tractable. An iterative method to determine the otherwise arbitrary parameters in such a scheme is proposed but not implemented.