Simulations of dispersed turbulent multiphase flow

Maxey, Martin; Patel, Bhavesh; Chang, Eugene; Wang, Lian‐Ping

doi:10.1016/s0169-5983(96)00042-1

Cited by 118 publications

(74 citation statements)

References 14 publications

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“…As additional examples, Maxey et al (1997) and Saw et al (2008) reported numerical and experimental evidence, respectively, of spatial clustering of dense particles in high-Re homogenous, isotropic turbulence. The dissipation-scale clustering was found to become stronger for increasing values of the Stokes number.…”

Section: Introductionmentioning

confidence: 98%

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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Section: Introductionmentioning

confidence: 98%

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

Lappa¹

2013

J. Fluid Mech.

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“…A fully resolved method which is based on matching explicit Stokes flow representations of flow near particles with computations on a grid has been proposed by Ory, Oguz and Prosperetti [2000]. The problem of particulates in turbulent flows has been considered by a few authors: Crowe, Chung, Troutt [1996], McLaughlin [1994], Maxey, Patel, Chang, Wang [1997]; these approaches use point particle approximations because fully resolved computations in turbulent flow are not presently possible. Numerical approaches to particulate flow based on the discrete Lattice Boltzmann equation have been presented by Ladd [1994Ladd [ , 1996Ladd [ , 1997 Aidun [1996], Aidun, Lu and Ding [1998] and Qi [1997Qi [ , 1999.…”

Section: Introductionmentioning

confidence: 99%

Fluidization of 1204 spheres: simulation and experiment

et al. 2002

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In this paper we study the fluidization of 1204 spheres at Reynolds numbers in the thousands using the method of distributed Lagrange multipliers. The results of the simulation are compared with a real experiment. This is the first direct numerical simulation of a real fluidized bed at the finite Reynolds number encountered in the applications. The simulations are processed like real experiments for straight lines in lot-log plots leading to power laws as in celebrated correlations of Richardson and Zaki [1954]. The numerical method allows for the first ever direct calculation of the slip velocity and other averaged values used in two-fluid continuum models. The computation and the experiment show that a single particle may be in balance under weight and drag for an interval of fluidizing velocities; the expectation that the fluidizing velocity is unique is not realized. The numerical method reveals that the dynamic pressure actually decreases slowly with the fluidizing velocity. Tentative interpretations of these new results are discussed.

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“…The microbubble limit was used in the PPDNS study of microbubbles in Wang and Maxey (1993b) and Maxey et al (1997). For the fully buoyant particle limit, the equation of motion becomes solvable to yield V À U ¼ ðV À UÞj t¼0 expðÀt=s p Þ with s p ¼ a 2 =ð3mÞ so the particle quickly approaches the fluid velocity.…”

Section: Lagrangian Tracking Of Particlesmentioning

confidence: 99%

Turbulent collision of inertial particles: Point-particle based, hybrid simulations and beyond

Wang

Rosa

Gao

et al. 2009

International Journal of Multiphase Flow

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a b s t r a c t Point-particle based direct numerical simulation (PPDNS) has been a productive research tool for studying both single-particle and particle-pair statistics of inertial particles suspended in a turbulent carrier flow. Here we focus on its use in addressing particle-pair statistics relevant to the quantification of turbulent collision rate of inertial particles. PPDNS is particularly useful as the interaction of particles with small-scale (dissipative) turbulent motion of the carrier flow is mostly relevant. Furthermore, since the particle size may be much smaller than the Kolmogorov length of the background fluid turbulence, a large number of particles are needed to accumulate meaningful pair statistics. Starting from the relative simple Lagrangian tracking of so-called ghost particles, PPDNS has significantly advanced our theoretical understanding of the kinematic formulation of the turbulent geometric collision kernel by providing essential data on dynamic collision kernel, radial relative velocity, and radial distribution function. A recent extension of PPDNS is a hybrid direct numerical simulation (HDNS) approach in which the effect of local hydrodynamic interactions of particles is considered, allowing quantitative assessment of the enhancement of collision efficiency by fluid turbulence. Limitations and open issues in PPDNS and HDNS are discussed. Finally, on-going studies of turbulent collision of inertial particles using large-eddy simulations and particle-resolved simulations are briefly discussed.

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Simulations of dispersed turbulent multiphase flow

Cited by 118 publications

References 14 publications

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

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

Fluidization of 1204 spheres: simulation and experiment

Turbulent collision of inertial particles: Point-particle based, hybrid simulations and beyond

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