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Etude expérimentale des fluctuations de vitesse, de température et de pression en turbulence développée

Abstract : The use of low temperature helium in fully developed turbulence experiments is crucial in the study of the statistical properties of the velocity and passive scalar fields : it offers an unbeatable range of Reynolds numbers and excellent stability conditions. The experiments presented in this work are performed in a confined geometry, between two rotating disks.

We first describe the energy transfers from scale to scale, pointing on the algebraic trend toward an asymptotic regime (Kolmogorov's 4/5 law) in the limit of very high Reynolds numbers. We discuss in detail the validity of the Kolmogorov equation in different flow configurations, and characterise the influence of the large scales on this regime.

Then we present new results concerning temperature fluctuation measurements, performed for the first time in low temperature helium. We characterise the passive scalar intermittency through the anomalous scaling laws. We show that the evolution of structure function exponents suggests a saturation at high orders, revealing statistics dominated by intens cliffs. We study the statistical properties of these cliffs, and give evidence of their self-similar distribution.

Last, we present new results about pressure fluctuations in turbulent flows, from an original experiment using cavitation in water. We qualitatively describe the low pressure coherent structures in this counter-rotating flow. We discuss their contribution to the skewed exponential pressure distribution, measured in the bulk of the flow, highlighting the relevance of large scales in the pressure fluctuation description.
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https://tel.archives-ouvertes.fr/tel-00002777
Contributor : Frederic Moisy <>
Submitted on : Friday, May 2, 2003 - 5:26:06 PM
Last modification on : Thursday, March 26, 2020 - 9:45:57 PM
Document(s) archivé(s) le : Monday, September 20, 2010 - 11:32:58 AM

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  • HAL Id : tel-00002777, version 2

Citation

Frederic Moisy. Etude expérimentale des fluctuations de vitesse, de température et de pression en turbulence développée. Dynamique des Fluides [physics.flu-dyn]. Université Pierre et Marie Curie - Paris VI, 2000. Français. ⟨tel-00002777v2⟩

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