CROSSOVER FROM HIGH TO LOW-REYNOLDS-NUMBER TURBULENCE

The Taylor-Reynolds and Reynolds number (Reλ and Re) dependence of the dimensionless energy dissipation rate cε=εLu1,rms3 is derived for statistically stationary isotropic turbulence, employing the results of a variable range mean field theory. Here ε is the energy dissipation rate, L the (fixed) outer length scale, and u1,rms a rms velocity component. Results for cε(Reλ) and also for Reλ(Re) are in good agreement with experiment. Using the Re dependence of cε we account for the time dependence of the mean vorticity ω(t) for decaying isotropic turbulence. The lifetime of decaying turbulence, depending on the initial Reλ,0 is predicted to saturate at 0.18L2ν??»Reλ,02 (ν the viscosity) for large Reλ,0. © 1994 The American Physical Society.