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Communication Dans Un Congrès Année : 2002

Prandtl and wall effects in hard turbulence convection

Résumé

Using low-temperature gaseous helium close to the critical point, we investigate the {P}randtl-number dependence of the effective heat conductivity ({N}usselt number) for a 1/2 aspect ratio {R}ayleigh-{B}énard cell. Very weak dependence is observed in the range 0.7 < Pr < 21; 2 * 10/sup 8/ < Ra < 2 * 10/sup 10/: the absolute value of the average logarithmic slope delta = ( delta ln Nu/ delta ln Pr)/sub Ra/ is smaller than 0.03. A bimodality of Nu, with 7{\%} difference between the two sets of data, is observed, which could explain some discrepancies between precise previous experiments in this range.
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Dates et versions

hal-00521144 , version 1 (25-09-2010)

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  • HAL Id : hal-00521144 , version 1

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Philippe-Emmanuel Roche, Benjamin Attias, Bernard Castaing, Benoît Chabaud, Bernard Hébral, et al.. Prandtl and wall effects in hard turbulence convection. 9th European Turbulence Conference, Jul 2002, Southampton, UK, France. pp.163. ⟨hal-00521144⟩
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