High-resolution temperature profiling in the Î Chamber: Variability of statistical properties of temperature fluctuations
This study delves into the small-scale temperature structure inside the turbulent convection Î Chamber under three temperature differences (10, 15, and 20âK) at Rayleigh number Raâ¼109 and Prandtl number Prâ0.7. We performed high-frequency measurements (2âkHz) with the UltraFast Thermometer (UFT) at selected points along the vertical axis. The miniaturized design of the sensor with a resistive platinum-coated tungsten wire, 2.5âµm thick and 3âmm long, mounted on a miniature wire probe, allowed for vertically undisturbed temperature profiling through the chamber's depth spanning from 8âcm above the bottom to 5âcm below the top. The collected data, consisting of 19 and 3âmin time series, were used to investigate the variability of the temperature field within the chamber, aiming to better address scientific questions related to its primary objective: understanding small-scale aerosolâcloud interactions. The analyses reveal substantial variability in both variance and skewness of temperature distributions near the top and bottom plates and in the bulk (central) region, which were linked to local thermal plume dynamics. We also identified three spectral regimes termed âinertial rangeâ (slopes of â¼-7/5), âtransition rangeâ (slopes of â¼-3), and âdissipative rangeâ, characterized by slopes of â¼-7. Furthermore, the analysis showed a power law relationship between the periodicity of large-scale circulation (LSC) and the temperature difference. Notably, the experimental results are in good agreement with direct numerical simulation (DNS) conducted under similar thermodynamic conditions, illustrating a comparative analysis of this nature.
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https://n2t.net/ark:/85065/d7r49w66
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2016-01-01T00:00:00Z
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2025-06-20T00:00:00Z
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