BOUNDARY-LAYER AND SCALING PROPERTIES IN TURBULENT THERMAL-CONVECTION

We describe an experiment which has been designed to measure both spatial and temporal features of turbulent thermal convection in a fluid layer heated from below. Specifically we have studied the dependence of the heat flow vs. the Rayleigh number, the thermal boundary layer profile, the temperature probability distribution function, the frequency and wave number power spectra. All the results have been compared with recent theories. The relevant scales of the problem, the Bolgiano and dissipative lengths, are also computed as a function of control parameters.