Spectra and probability distributions of thermal flux in turbulent Rayleigh-Bénard convection

Abstract

The spectra of turbulent heat flux H(k) in Rayleigh-Bénard convection with and without uniform rotation are presented. The spectrum H(k) scales with wave number k as ∼k−2. The scaling exponent is almost independent of the Taylor number Ta and Prandtl number Pr for higher values of the reduced Rayleigh number r (>103). The exponent, however, depends on Ta and Pr for smaller values of r (<103). The probability distribution functions of the local heat fluxes are non-Gaussian and have exponential tails.