Diffusion of heavy particles in a turbulent flow

A Trajectory-Simulation Model for Heavy Particle Motion in Turbulent Flow

Journal of Fluids Engineering ◽

10.1115/1.3243673 ◽

1989 ◽

Vol 111 (4) ◽

pp. 492-494 ◽

Cited By ~ 23

Author(s):

Y. Zhuang ◽

J. D. Wilson ◽

E. P. Lozowski

Keyword(s):

Turbulent Flow ◽

Simulation Model ◽

Particle Motion ◽

Simple Procedure ◽

Heavy Particle ◽

Particle Dispersion ◽

Fluid Density ◽

Heavy Particles ◽

Trajectory Simulation ◽

Acceptable Agreement

For many purposes it is useful to be able to mimic the paths of heavy particles in a turbulent flow. This paper gives a simple procedure by which this may be achieved, provided particle spin is not important and under the restriction that the ratio of particle to fluid density exceeds about 1000. The procedure is related to the models of Faeth (1986) and Hunt and Nalpanis (1985). Simulation of the experiments of Snyder and Lumley (1971) yielded acceptable agreement with the observed rate of heavy particle dispersion.

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The mean velocity of slightly buoyant and heavy particles in turbulent flow in a pipe

Journal of Fluid Mechanics ◽

10.1017/s002211205800032x ◽

1958 ◽

Vol 4 (1) ◽

pp. 87-96 ◽

Cited By ~ 10

Author(s):

A. M. Binnie ◽

O. M. Phillips

Keyword(s):

Turbulent Flow ◽

Relative Density ◽

Terminal Velocity ◽

Neutral Density ◽

Mean Velocity ◽

Heavy Particles ◽

Horizontal Pipe ◽

The Mean ◽

The Times

A large number of small spheres of the same size were injected successively into a horizontal pipe conveying water at constant mean velocity, and their times of transit were measured. The mean velocity of the spheres that were either somewhat heavier or lighter than water was less than that of those of neutral density; for those having a terminal velocity in water within ± 1% of the mean velocity of the water in the pipe, the discrepancy was only about 0.1%. The dispersion of the times of transit of the spheres was almost independent of their density. A theory is developed to show how the mean velocity of the spheres depends upon their relative density and size.

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Collision rate between heavy particles in a model turbulent flow

Springer Proceedings in Physics - Advances in Turbulence XII ◽

10.1007/978-3-642-03085-7_5 ◽

2009 ◽

pp. 23-26

Author(s):

L. Ducasse ◽

A. Pumir

Keyword(s):

Turbulent Flow ◽

Collision Rate ◽

Heavy Particles

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Effects of roughness on particle dynamics in turbulent channel flows: a DNS analysis

Journal of Fluid Mechanics ◽

10.1017/jfm.2013.633 ◽

2014 ◽

Vol 739 ◽

pp. 465-478 ◽

Cited By ~ 33

Author(s):

Barbara Milici ◽

Mauro De Marchis ◽

Gaetano Sardina ◽

Enrico Napoli

Keyword(s):

Turbulent Flow ◽

Turbulent Flows ◽

Three Dimensional ◽

Wall Region ◽

Wall Roughness ◽

Turbulent Structures ◽

Two Phase ◽

Heavy Particles ◽

Turbulent Channel Flows ◽

Lagrangian Tracking

AbstractDeposition and resuspension mechanisms in particle-laden turbulent flows are dominated by the coherent structures arising in the wall region. These turbulent structures, which control the turbulent regeneration cycles, are affected by the roughness of the wall. The particle-laden turbulent flow in a channel bounded by irregular two-dimensional rough surfaces is analysed. The behaviour of dilute dispersions of heavy particles is analysed using direct numerical simulations (DNS) to calculate the three-dimensional turbulent flow and Lagrangian tracking to describe the turbophoretic effect associated with two-phase turbulent flows in a complex wall-bounded domain. Turbophoresis is investigated in a quantitative way as a function of the particle inertia. The analysis of the particle statistics, in term of mean particle concentration and probability density function (p.d.f.) of wall-normal particle velocity, shows that the wall roughness produces a completely different scenario compared to the classical smooth wall. The effect of the wall roughness on the particle mass flux is shown for six particle populations having different inertia.

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Intermittent distribution of heavy particles in a turbulent flow

Physics of Fluids ◽

10.1063/1.1755722 ◽

2004 ◽

Vol 16 (7) ◽

pp. L47-L50 ◽

Cited By ~ 95

Author(s):

Gregory Falkovich ◽

Alain Pumir

Keyword(s):

Turbulent Flow ◽

Heavy Particles

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Where do small, weakly inertial particles go in a turbulent flow?

Journal of Fluid Mechanics ◽

10.1017/jfm.2012.72 ◽

2012 ◽

Vol 698 ◽

pp. 160-167 ◽

Cited By ~ 26

Author(s):

Mathieu Gibert ◽

Haitao Xu ◽

Eberhard Bodenschatz

Keyword(s):

Turbulent Flow ◽

Particle Density ◽

Inertial Particles ◽

Flow Conditions ◽

Particle Inertia ◽

Heavy Particles ◽

Preferential Sampling ◽

Fully Developed Turbulent Flow ◽

Kolmogorov Scale ◽

Preferential Alignment

AbstractWe report experimental results on the dynamics of heavy particles of the size of the Kolmogorov scale in a fully developed turbulent flow. The mixed Eulerian structure function of two-particle velocity and acceleration difference vectors $\langle {\delta }_{r} \mathbi{v}\boldsymbol{\cdot} {\delta }_{r} {\mathbi{a}}_{\mathbi{p}} \rangle $ was observed to increase significantly with particle inertia for identical flow conditions. We show that this increase is related to a preferential alignment between these dynamical quantities. With increasing particle density the probability for those two vectors to be collinear was observed to grow. We show that these results are consistent with the preferential sampling of strain-dominated regions by inertial particles.

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Prevalence of the sling effect for enhancing collision rates in turbulent suspensions

Journal of Fluid Mechanics ◽

10.1017/jfm.2014.259 ◽

2014 ◽

Vol 749 ◽

pp. 841-852 ◽

Cited By ~ 29

Author(s):

Michel Voßkuhle ◽

Alain Pumir ◽

Emmanuel Lévêque ◽

Michael Wilkinson

Keyword(s):

Phase Space ◽

Turbulent Flow ◽

Suspended Particles ◽

Collision Rate ◽

Heavy Particles ◽

Dominant Mechanism ◽

Preferential Concentration ◽

High Turbulence

AbstractTurbulence facilitates collisions between particles suspended in a turbulent flow. Two effects have been proposed that can enhance the collision rate at high turbulence intensities: ‘preferential concentration’ (a clustering phenomenon) and the ‘sling effect’ (arising from the formation of caustic folds in the phase space of the suspended particles). We have determined numerically the collision rate of small heavy particles as a function of their size and densities. The dependence on particle densities allows us to quantify the contribution of the sling effect to the collision rate. Our results demonstrate that the sling effect provides the dominant mechanism to the enhancement of the collision rate of particles, when inertia becomes significant.

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