CONDITIONAL AVERAGES IN CONVECTIVE TURBULENCE

Two exact results are presented for the thermal dissipation in a Rayle igh-Benard geometry. The first result expresses the conditional dissip ation at each value of theta within the entire volume of the system in terms of the thermal flux and the PDF for theta. The second gives the conditional dissipation in a region of the cell in terms of the condi tional flux into the region. These results are used to argue that the observed stretched exponential PDF in the central region must be conne cted with the behavior near the boundary.