How gravity and size affect the acceleration statistics of bubbles in turbulence
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چکیده
We report the results of the first systematic Lagrangian experimental investigation in a previously unexplored regime of very light (air bubbles in water) and large (D/η 1) particles in turbulence. Using a traversing camera setup and particle tracking, we study the Lagrangian acceleration statistics of ∼3mm diameter (D) bubbles in a water tunnel with nearly homogeneous and isotropic turbulence generated by an active grid. The Reynolds number (Reλ) is varied from 145 to 230, resulting in size ratios, D/η, in the range of 7.3–12.5, where η is the Kolmogorov length scale. The experiments reveal that gravity increases the acceleration variance and reduces the intermittency of the probability density function (PDF) in the vertical direction. Once the gravity 6 Authors to whom any correspondence should be addressed. New Journal of Physics 14 (2012) 105017 1367-2630/12/105017+14$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft
منابع مشابه
Modulation of homogeneous turbulence seeded with finite size bubbles or particles
0301-9322/$ see front matter 2009 Elsevier Ltd. A doi:10.1016/j.ijmultiphaseflow.2009.11.001 * Corresponding author. Tel.: +1 401 863 1482; fax E-mail address: [email protected] (M.R. Max 1 Present address: Department of Mathematics, Purd IN 47907, USA. The dynamics of homogeneous, isotropic turbulence seeded with finite sized particles or bubbles is investigated in a series of numerical simu...
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تاریخ انتشار 2012