Answers are grounded in this paper and cite their sources.
A diffusion approximation is derived for the transfer of spectral components of mean-square fluctuations of a passive scalar quantity advected by an isotropic turbulent flow. This approximation, expected to be most useful for very large Reynolds numbers, preserves nonnegative spectral components and chaotic equilibrium solutions, as well as producing −53 power advection range spectra in appropriate circumstances. A comparison is made with some observations of Gibson and Schwarz at a Prandtl number of 7. Cutoff difficulties at large wavenumber make the approximation questionable for Prandtl numbers much greater than 7.
No takes yet. Share an insight, caveat, or question.
C. E. Leith (1968) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: