SPECTRA OF VELOCITY AND TEMPERATURE-FLUCTUATIONS WITH CONSTANT ENTROPY FLUX OF FULLY-DEVELOPED FREE-CONVECTIVE TURBULENCE

It is shown that the frequency-temperature spectrum recently observed by Wu et al. in developed convective turbulence, F(TT)(omega) is-proportional-to-omega-1/4, follows from the condition that the entropy flux in k space is constant. just as the Kolmogorov-Obukhov spectrum of barotropic turbulence, F(VV)(k) congruent-to (epsilon/rho)2/3k-11/3, follows from the condition that kinetic-energy flux-epsilon(k) = epsilon. On the contrary, for convective turbulence-epsilon(k) changes as k-4/5 because of conversion of kinetic energy into a potential energy, which leads to a stronger k dependence of the double velocity moment [F(VV)(k) infinity k-21/5] than that for barotropic turbulence.