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Intermittency and inertial particle entrainment at a turbulent interface: the effect of the large-scale eddies

Published online by Cambridge University Press:  03 February 2012

G. H. Good ,
S. Gerashchenko  and
Z. Warhaft
G. H. Good
Affiliation:
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA and International Collaboration for Turbulence Research
S. Gerashchenko
Affiliation:
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA and International Collaboration for Turbulence Research
Z. Warhaft*
Affiliation:
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA and International Collaboration for Turbulence Research Atkinson Center for a Sustainable Future, Cornell University, Ithaca, NY 14853, USA
*
†Email address for correspondence: zw16@cornell.edu
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Abstract

We present measurements of mean and conditional number densities, radial distribution functions (r.d.f.s), velocities and accelerations of sub-Kolmogorov-scale water droplets entraining at a shearless turbulence–turbulence interface (TTI) and a turbulence–non-turbulence interface (TNI). We thus look at statistics of an inhomogeneous inertial particle field in both homogeneous and inhomogeneous turbulence. As in a previous communication (Gerashchenko, Good & Warhaft J. Fluid Mech., vol. 818, 2011, pp. 293–303), an active grid produces high-Reynolds number turbulence on either one or both sides of a splitter plate in a wind tunnel. Sprays seed droplets on one side of the splitter plate, while screens dampen turbulence in the adjacent flow for the TNI. Gravitational and inertial effects are isolated by turning of the apparatus with respect to gravity. We parameterize the droplets under homogeneous conditions, where it is demonstrated that both the sweeping and loitering effects on the droplet settling velocities are present. In the inhomogeneous conditions, we show that the droplets are entrained in bulk, resulting in large-scale clusters and preserving the droplet-ambient conditions of the seeded side of the flows.

JFM classification

Turbulent Flows: Intermittency Mixing: Turbulent mixing
Type
Papers
Information
Journal of Fluid Mechanics , Volume 694 , 10 March 2012 , pp. 371 - 398
Copyright
Copyright © Cambridge University Press 2012

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Footnotes

‡

Present address: Now with the P-23 Extreme Fluids Team, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.

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