Measurement of particle and bubble accelerations in turbulence

Abstract : We use an extended laser Doppler technique to track optically the velocity of individual particles in a high Reynolds number turbulent flow. The particle sizes are of the order of the Kolmogorov scale and the time resolution, 30 microseconds, resolves the fastest scales of the fluid motion. Particles are tracked for mean durations of the order of 10 Kolmogorov time scales. The fastest scales of the particle motion are resolved and the particle acceleration is measured. For neutrally buoyant particles, our measurement matches the performance of the silicon strip detector technique introduced at Cornell University~\cite{Voth,MordantCornell}. This reference dynamics is then compared to that of slightly heavier solid particles (density 1.4) and to air bubbles. We observe that the acceleration variance strongly depends on the particle density: bubbles experience higher accelerations than fluid particles, while heavier particles have lower accelerations. We find that the probability distribution functions of accelerations normalized to the variance are very close although the air bubbles have a much faster dynamics.
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https://hal-ens-lyon.archives-ouvertes.fr/ensl-00167302
Contributor : Jean-François Pinton <>
Submitted on : Saturday, August 18, 2007 - 10:22:20 AM
Last modification on : Sunday, March 31, 2019 - 1:17:43 AM
Long-term archiving on : Friday, April 9, 2010 - 12:55:22 AM

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  • HAL Id : ensl-00167302, version 1
  • ARXIV : 0708.3350

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Romain Volk, Nicolas Mordant, Gautier Verhille, Jean-François Pinton. Measurement of particle and bubble accelerations in turbulence. 2007. ⟨ensl-00167302⟩

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