The scaling behavior of the temperature structure functions in turbulent convection is found to be different for length scales below and above the Bolgiano scale. Both sets of the exponents are well described by log-Poisson statistics. The parameter ${\beta }_T$ which measures the degree of intermittency is the same for the two regimes of scales and is consistent with the corresponding value for the passive scalar field. A balance between thermal forcing and nonlinear velocity advection, which is a key ingredient leading to Bolgiano scaling, is also checked.

• Received 18 May 1999

DOI:https://doi.org/10.1103/PhysRevE.61.R33