THERMODYNAMICAL VERSUS LOG-POISSON DISTRIBUTION IN TURBULENCE

The thermodynamical model of intermittency in fully developed turbulen ce due to Castaing (B. Castaing, J. Phys. II France 6 (1996) 105) is i nvestigated and compared with the log-Poisson model (Z-S, She, E. Leve que, Phys. Rev. Lett. 72 (1994) 336). It is shown that the thermodynam ical model obeys general scaling laws and corresponds to the degenerat e class of scale-invariant statistics. We also find that its structure function shapes have physical behaviors similar to the log-Poisson's one. The only difference between them lies in the convergence of the l og-Poisson's structure functions and divergence of the thermodynamical one. As far as the comparison with experiments on intermittency is co ncerned, they are indifferent. (C) 1998 Published by Elsevier Science B.V.