Schematic of both cells, clarifying the notations.
(a) Picture of the first cell (without the insulation and the thermal screen). The L structures used for temperature correlation measurements are shown in the channel. (b) Picture of the second cell (without the insulation). The short version of the bridge (5 cm high ×2.5 cm wide) can be seen in the channel.
The correlation function for various in the high power case (235 W). The dots correspond to the position of the highest peak and its symmetric compared to . The squares mark the value of for the different , from the darker to the lighter: 4 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm (twice), 60 mm, 70 mm, and 100 mm. The blue (top) curve corresponds to the autocorrelation of one sensor (i.e., ).
The correlation function vs . The lines are fits with an exponential decay.
The spectra of the bridge output, for various Ra values (second cell, ). The lines correspond to the fit used for extracting . The range for the fit is signaled in red (gray) on the spectrum.
Temperature gradient vs the height in the cell, for the second cell. Only full symbols correspond to real measurements. Open symbols are simply symmetric to the full ones compared to the middle of the cell. The two vertical bars signal the ends of the channel. The thick horizontal line stands for the average of in the center of the channel. The lower and upper horizontal lines correspond to ±5% of this mean value.
Evolution of Nu (full symbols) and (open symbols) vs . First cell: (○) ; (▽) ; (◼) . Second cell: (◇) . Full line, proposed average law for Nu results: . Dotted line, proposed average law for results:
Dependence of vs Re for both cells. Same symbols as in Fig. 7. The line correspond to a fit of our data with the formula: , with .
Two typical instantaneous maps of the two velocity components algebraic values. Note that the color code is not the same for and . Top: . Bottom: (see text).
Schematic dynamics of the reversals.
Time averages of and .
(full line) and (dotted line) profiles. See the text for the definition of these and time averages.
The Reynolds stresses (○), (▽), and (△), vs , for the lowest power (93 W). The full symbols correspond to the range of the fit (, ). The lines show the proposed fit.
Summary of the various quantities directly measured or derived from the measurements for two experiments at the average temperature of , in the first cell. The last column allows to distinguish between the approximately constant quantities and the varying ones.
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