scholarly journals Coherent Particle Structures in High-Prandtl-Number Liquid Bridges

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Ilya Barmak ◽  
Francesco Romanò ◽  
Parvathy Kunchi Kannan ◽  
Hendrik C. Kuhlmann
Keyword(s):  
Prandtl Number ◽  
Finite Size ◽  
Spherical Particles ◽  
Motion Modeling ◽  
Coupling Approach ◽  
High Prandtl Number ◽  
Tubular Flow ◽  
The One ◽  
Flow Boundaries ◽  
Finite Particle

AbstractClustering of small rigid spherical particles into particle accumulation structures (PAS) is studied numerically for a high-Prandtl-number (Pr = 68) thermocapillary liquid bridge. The one-way-coupling approach is used for calculation of the particle motion, modeling PAS as an attractor for a single particle. The attractor is created by dissipative forces acting on the particle near the boundary due to the finite size of the particle. These forces can dramatically deflect the particle trajectory from a fluid pathline and transfer it to certain tubular flow structures, called Kolmogorov–Arnold–Moser (KAM) tori, in which the particle is focused and from which it might not escape anymore. The transfer of particles can take place if a KAM torus, which is a property of the flow without particles, enters the narrow boundary layer on the flow boundaries in which the particle experiences extra forces. Since the PAS obtained in this system depends mainly on the finite particle size, it can be classified as a finite-size coherent structure (FSCS).

Finite-size coherent particle structures in high-Prandtl-number liquid bridges

2021 ◽  
Vol 6 (8) ◽  
Author(s):  
Ilya Barmak ◽  
Francesco Romanò ◽  
Hendrik C. Kuhlmann
Keyword(s):  
Prandtl Number ◽  
Finite Size ◽  
Liquid Bridges ◽  
High Prandtl Number

An Equation of Motion for Particles of Finite Reynolds Number and Finite Size

2009 ◽  
Author(s):  
Eric Loth ◽  
Andrew J. Dorgan
Keyword(s):  
Particle Size ◽  
Reynolds Number ◽  
Slip Surface ◽  
Finite Size ◽  
Grid Cell ◽  
Equation Of Motion ◽  
Spherical Particles ◽  
Spatial Gradients ◽  
Order Of Magnitude ◽  
Finite Particle

In order to simulate the motion of bubbles, drops, and particles, it is often important to consider finite Reynolds number effects on drag, lift, torque and history force. Herein, an equation of motion is developed for spherical particles with a no-slip surface based on theoretical analysis, experimental data and surface-resolved simulations. The equation of motion is then extended to account for finite particle size. This extension is critical for particles which will have a size significantly larger than the grid cell size, particularly important for bubbles and low-density particles. The extension to finite particle size is accomplished through spatial-averaging (both volume-based and surface-based) of the continuous flow properties. This averaging is consistent with the Faxen limit for solid spheres at small Reynolds numbers and added mass and fluid stress forces at inviscid limits. The finite Rep corrections are shown to have good agreements with experiments and resolved-surface simulations. The finite size corrections are generally fourth-order accurate and an order of magnitude more accurate than point-force expressions (which neglect quadratic and higher spatial gradients) for particles with size on the order of the gradient length-scales. However, further work is needed for more quantitative assessment of the truncation terms and the overall model robustness and accuracy in complex flows.

Onset of temporal aperiodicity in high Prandtl number liquid bridge under terrestrial conditions

2004 ◽  
Vol 16 (5) ◽  
pp. 1746-1757 ◽  
Author(s):  
D. E. Melnikov ◽  
V. M. Shevtsova ◽  
J. C. Legros
Keyword(s):  
Prandtl Number ◽  
Liquid Bridge ◽  
High Prandtl Number

Particle-Laden Turbulence: Progress and Perspectives

2021 ◽  
Vol 54 (1) ◽  
Author(s):  
Luca Brandt ◽  
Filippo Coletti
Keyword(s):  
Fluid Dynamics ◽  
Fluid Mechanics ◽  
Online Publication ◽  
Granular Media ◽  
Finite Size ◽  
Spherical Particles ◽  
Annual Review ◽  
Publication Date ◽  
Zero Gravity ◽  
Inertial Particles

This review is motivated by the fast progress in our understanding of the physics of particle-laden turbulence in the last decade, partly due to the tremendous advances of measurement and simulation capabilities. The focus is on spherical particles in homogeneous and canonical wall-bounded flows. The analysis of recent data indicates that conclusions drawn in zero gravity should not be extrapolated outside of this condition, and that the particle response time alone cannot completely define the dynamics of finite-size particles. Several breakthroughs have been reported, mostly separately, on the dynamics and turbulence modifications of small inertial particles in dilute conditions and of large weakly buoyant spheres. Measurements at higher concentrations, simulations fully resolving smaller particles, and theoretical tools accounting for both phases are needed to bridge this gap and allow for the exploration of the fluid dynamics of suspensions, from laminar rheology and granular media to particulate turbulence. Expected final online publication date for the Annual Review of Fluid Mechanics, Volume 54 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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