Small-scale variation of convected quantities like temperature in turbulent fluid Part 2. The case of large conductivity

The analysis reported in Part 1 is extended here to the case in which the conductivity κ is large compared with the viscosity ν, the conduction 'cut-off' to the θ-spectrum then being at wave-number (ε/κ3)¼. It is shown, with a plausible and consistent hypothesis, that the convective supply of . The consequent form of the theta;-spectrum within this same wave-number range is The way in which conduction influences (and restricts) the effect of convection on the distribution of θ at these wave-numbers beyond the conduction cut-off is discussed.