Sedimentation of inertial monodisperse suspensions of cubes and spheres

2021 ◽  
Vol 6 (4) ◽  
Author(s):  
Arman Seyed-Ahmadi ◽  
Anthony Wachs
Keyword(s):  
Monodisperse Suspensions

scholarly journals Development of particle migration in pressure-driven flow of a Brownian suspension

2007 ◽  
Vol 581 ◽  
pp. 437-451 ◽  
Author(s):  
DENIS SEMWOGERERE ◽  
JEFFREY F. MORRIS ◽  
ERIC R. WEEKS
Keyword(s):  
Flow Rate ◽  
Colloidal Particles ◽  
Volume Fraction ◽  
Rectangular Cross Section ◽  
Sample Volume ◽  
Particle Migration ◽  
Entrance Length ◽  
Uniform Steady State ◽  
Monodisperse Suspensions ◽  
Pressure Driven Flow

An experimental investigation into the influence of Brownian motion on shear-induced particle migration of monodisperse suspensions of micrometre-sized colloidal particles is presented. The suspension is pumped through a 50 μm × 500 μm rectangular cross-section glass channel. The experiments are characterized chiefly by the sample volume fraction (φ = 0.1 − 0.4), and the flow rate expressed as the Péclet number (Pe = 10 − 400). For each experiment we measure the entrance length, which is the distance from the inlet of the channel required for the concentration profile to develop to its non-uniform steady state. The entrance length increases strongly with increasing Pe for Pe ≪ 100, in marked contrast to non-Brownian flows for which the entrance length is flow-rate independent. For larger Pe, the entrance length reaches a constant value which depends on the other experimental parameters. Additionally, the entrance length decreases with increasing φ; this effect is strongest for low φ. Modelling of the migration based on spatial variation of the normal stresses due to the particles captures the primary features observed in the axial evolution over a range of Pe and φ.

scholarly journals Influence of walls on the migration of non-Brownian spherical particles in creeping flow: a lattice Boltzmann study

2011 ◽  
Vol 369 (1945) ◽  
pp. 2387-2395 ◽  
Author(s):  
Ernesto Monaco ◽  
Gunther Brenner
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Creeping Flow ◽  
Spherical Particles ◽  
Particle Displacement ◽  
Initial Particle ◽  
Preliminary Results ◽  
Monodisperse Suspensions ◽  
Different Diameters ◽  
Boltzmann Method

The influence of walls on binary encounters of spherical particles under creeping flow is studied by means of the lattice Boltzmann method. Depending on the initial particle displacement different behaviours can be observed, including the ‘swapping’ trajectories. The domain of the swapping trajectories is identified for interacting spheres with the same diameter; some preliminary results are given for the case of two spheres with different diameters. Finally, the influence of particle swapping on the dynamics of monodisperse suspensions is also described.

Dynamics of complete turbulence suppression in turbidity currents driven by monodisperse suspensions of sediment

2012 ◽  
Vol 712 ◽  
pp. 384-417 ◽  
Author(s):  
Mrugesh Shringarpure ◽  
Mariano I. Cantero ◽  
S. Balachandar
Keyword(s):  
Reynolds Stress ◽  
Suspended Sediments ◽  
Stable Stratification ◽  
Turbidity Currents ◽  
Vortical Structures ◽  
Threshold Size ◽  
Turbulence Suppression ◽  
Sediment Size ◽  
Ability To Regenerate ◽  
Monodisperse Suspensions

AbstractTurbidity currents derive their motion from the excess density imposed by suspended sediments. The settling tendency of sediments is countered by flow turbulence, which expends energy to keep them in suspension. This interaction leads to downward increasing concentration of suspended sediments (stable stratification) in the flow. Thus in a turbidity current sediments play the dual role of sustaining turbulence by driving the flow and damping turbulence due to stable stratification. By means of direct numerical simulations, it has been shown previously that stratification above a threshold can substantially reduce turbulence and possibly extinguish it. This study expands the simplified model by Cantero et al. (J. Geophys. Res., vol. 114, 2009a, C03008), and puts forth a proposition that explains the mechanism of complete turbulence suppression due to suspended sediments. In our simulations it is observed that suspensions of larger sediments lead to stronger stratification and, above a threshold size, induce an abrupt transition in the flow to complete turbulence suppression. It has been widely accepted that hairpin and quasi-streamwise vortices are key to sustaining turbulence in wall-bounded flows, and that only vortices of sufficiently strong intensity can spawn the next generation of vortices. This auto-generation mechanism keeps the flow populated with hairpin and quasi-streamwise vortical structures and thus sustains turbulence. From statistical analysis of Reynolds stress events and visualization of flow structures, it is observed that settling sediments damp the Reynolds stress events (Q2 events), which means a reduction in both the strength and spatial distribution of vortical structures. Beyond the threshold sediment size, the existing vortical structures in the flow are damped to an extent where they lose their ability to regenerate the subsequent generation of turbulent vortical structures, which ultimately leads to complete turbulence suppression.

SIMULATION OF BIDISPERSE MAGNETORHEOLOGICAL FLUIDS

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2732-2738 ◽  
Author(s):  
DAVID KITTIPOOMWONG ◽  
DANIEL J. KLINGENBERG ◽  
JOHN C. ULICNY
Keyword(s):  
Yield Stress ◽  
Shear Behavior ◽  
Magnetorheological Fluids ◽  
Steady Shear ◽  
Experimental Results ◽  
Small Particles ◽  
Monodisperse Suspensions

A method for simulating the steady-shear behavior of bidisperse, nonlinearly magnetizable MR suspensions is described. Results show that the yield stress of suspensions containing mixtures of large and small particles is larger than that of monodisperse suspensions, in agreement with previous experimental results.

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