Temperature fluctuations and heat transport in partitioned supergravitational thermal turbulence.

We report an experimental study of the local temperature fluctuations δT and heat transport in a partitioned supergravitational turbulent convection system. Due to the dynamics of zonal flow in the normal system without partition walls, the probability density function (PDF) at a position in the mixing zone exhibits a downward bending shape, suggesting that the multi-plume clustering effect plays an important role. In partitioned system, zonal flow is suppressed and the PDFs indicate that the single-plume effect is dominant. Moreover, statistical analysis shows that the PDF of δT is sensitive to supergravity. Additionally, the thermal spectra follow P(f) ∼ f−5 in the normal system, which is relevant to the zonal flow. The absolute value of the scaling exponent of P(f) and the scaling range become small in the partitioned system, which provides another evidence for the influence of zonal flow on the energy cascade. Further, heat transfer enhancement is found in the partitioned system, which may result from zonal flow being restricted and then facilitating the radial movement of thermal plumes to the opposite conducting cylinder. This work may provide insights into the flow and heat transport control of some engineering and geophysical flows. [ABSTRACT FROM AUTHOR]