Particles in Turbulent Flows

Sinaiski, Emmanuil G.; Zaichik, L. I.; Alipchenkov, V. M.

doi:10.1002/9783527626250

Cited by 65 publications

(84 citation statements)

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“…, and b i are the so-called Csanady factors, which are used to account for the crossing trajectory and continuity effects [3,25,135,142]. When the reference system is aligned with the mean, or filtered, slip velocity, the Csanady factors can be defined as (see [83,86] for details):…”

Section: Where T L Sg S Is the Lagrangian Sgs Timescale Of The Fluidmentioning

confidence: 99%

Large-eddy simulation of turbulent dispersed flows: a review of modelling approaches

Marchioli

2017

Acta Mech

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In large-eddy simulation (LES) of turbulent dispersed flows, modelling and numerical inaccuracies are incurred because LES provides only an approximation of the filtered velocity. Interpolation errors can also occur (on coarse-grained domains, for instance). These inaccuracies affect the estimation of the forces acting on particles, obtained when the filtered fluid velocity is supplied to the Lagrangian equation of particle motion, and accumulate in time. As a result, particle trajectories in LES fields progressively diverge from particle trajectories in DNS fields, which can be considered as the exact numerical reference: the flow fields seen by the particles become less and less correlated, and the forces acting on particles are evaluated at increasingly different locations. In this paper, we review models and strategies that have been proposed in the EulerianLagrangian framework to correct the above-mentioned sources of inaccuracy on particle dynamics and to improve the prediction of particle dispersion in turbulent dispersed flows.

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Section: Where T L Sg S Is the Lagrangian Sgs Timescale Of The Fluidmentioning

confidence: 99%

Large-eddy simulation of turbulent dispersed flows: a review of modelling approaches

Marchioli

2017

Acta Mech

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“…The study of such phenomena is wide ranging (see, e.g., Zohdi, 2007;Zaichik et al, 2008) and touches various scientific fields, including (but not limited to) environmental phenomena, thermal and materials engineering, crystal growth, life science and many other related topics.…”

Section: Introductionmentioning

confidence: 99%

On the variety of particle accumulation structures under the effect of g-jitters

Lappa¹

2013

J. Fluid Mech.

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The present analysis extends the author's earlier work (Lappa, Phys. Fluids 25(1) and Chaos 23(1)) on the properties of patterns formed by the spontaneous accumulation and ordering of solid particles in certain types of flow (with a toroidal structure and a traveling wave propagating in the azimuthal direction) by considering the potential impact of "vibrations" (gjitters) on such dynamics. It is shown that a kaleidoscope of possible variants exist whose nature and variety calls for a concerted analysis using the tools of computational fluid-dynamics in synergy with dimensional arguments and existing theories on the effect of periodic accelerations on fluid systems.A possible categorization of the observed phenomena is introduced according to the type and scale of "defects" displayed by the emerging particle aggregates with respect to unperturbed (vibrationless) conditions. It is shown that the resulting degree of "turbulence" depends essentially on the direction (), amplitude () and frequency () of the applied inertial disturbance. A range of amplitudes and frequencies exist where the formation of recognizable particle structures is prevented. A quantitative map (in the - plane) for their occurrence is derived with the express intent of supporting the optimization of future experiments to be performed in space.

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“…Note that it is sometimes convenient to introduce the Stokes number defined as u t    rel Stk to estimate the dynamic nonequilibrium of inertial particles in a viscous medium [43,44]. In our case, it is sufficient to compare directly the length of the droplet relaxation path and the height of a single horizontal layer of the computational region (see Fig.…”

Section: Transient Heat Transfer Modelmentioning

confidence: 99%

A simplified model for the shielding of fire thermal radiation by water mists

Dombrovsky

Dembele

Wen

2016

International Journal of Heat and Mass Transfer

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A solution for the complete problem of attenuation of fire radiation by water mist is presented. This solution is based on simplified approaches for the spectral radiative properties of water droplets, the radiative transfer in the absorbing and scattering mist, and transient heat transfer taking into account partial evaporation of water mist. A computational study of the conventional model problem indicates the role of the main parameters and enables one to formulate some recommendations to optimize possible engineering solutions. The method developed is also applied to more realistic case study of a real fire. It is suggested to decrease the size of supplied water droplets with the distance from the irradiated surface of the mist layer. The advantage of this engineering solution is confirmed by numerical calculations. Potential possibility of microwave monitoring of water mist parameters is analyzed on the basis of Mie theory calculations.

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Particles in Turbulent Flows

Cited by 65 publications

References 0 publications

Large-eddy simulation of turbulent dispersed flows: a review of modelling approaches

Large-eddy simulation of turbulent dispersed flows: a review of modelling approaches

On the variety of particle accumulation structures under the effect of g-jitters

A simplified model for the shielding of fire thermal radiation by water mists

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