STATISTICS OF TEMPERATURE INCREMENTS IN FULLY-DEVELOPED TURBULENCE .1. THEORY

Using a method recently proposed by Sinai and Yakhot, we obtain the eq uation for the probability density function (pdf) of the temperature i ncrements in fully developed turbulence. The closure problem is reduce d to the determination of two conditional expectations and can be carr ied out mainly by requiring isotropy and a weak correlation of the phy sical variables. As a consequence of our analysis, we show that the pd f is nearly Gaussian about zero and then has a stretched exponential b ehavior for large fluctuations.