scholarly journals Lattice Boltzmann simulations on the tumbling to tank-treading transition: effects of membrane viscosity

2021 ◽  
Vol 379 (2208) ◽  
pp. 20200395 ◽  
Author(s):  
Fabio Guglietta ◽  
Marek Behr ◽  
Luca Biferale ◽  
Giacomo Falcucci ◽  
Mauro Sbragaglia
Keyword(s):  
Lattice Boltzmann ◽  
Viscosity Ratio ◽  
Dynamics Simulation ◽  
Theme Issue ◽  
Membrane Viscosity ◽  
Lattice Boltzmann Simulations ◽  
Realistic Description ◽  
Transition Effects ◽  
Lattice Boltzmann Models ◽  
Range Of Values

The tumbling to tank-treading (TB-TT) transition for red blood cells (RBCs) has been widely investigated, with a main focus on the effects of the viscosity ratio λ (i.e., the ratio between the viscosities of the fluids inside and outside the membrane) and the shear rate γ ˙ applied to the RBC. However, the membrane viscosity μ m plays a major role in a realistic description of RBC dynamics, and only a few works have systematically focused on its effects on the TB-TT transition. In this work, we provide a parametric investigation on the effect of membrane viscosity μ m on the TB-TT transition for a single RBC. It is found that, at fixed viscosity ratios λ , larger values of μ m lead to an increased range of values of capillary number at which the TB-TT transition occurs; moreover, we found that increasing λ or increasing μ m results in a qualitatively but not quantitatively similar behaviour. All results are obtained by means of mesoscale numerical simulations based on the lattice Boltzmann models. This article is part of the theme issue ‘Progress in mesoscale methods for fluid dynamics simulation’.

Effects of Inertia and Viscosity on Single Droplet Deformation in Confined Shear Flow

2013 ◽  
Vol 13 (3) ◽  
pp. 706-724 ◽  
Author(s):  
Samaneh Farokhirad ◽  
Taehun Lee ◽  
Jeffrey F. Morris
Keyword(s):  
Reynolds Number ◽  
Shear Flow ◽  
Viscous Fluid ◽  
Lattice Boltzmann ◽  
Viscosity Ratio ◽  
Diffuse Interface ◽  
Single Droplet ◽  
Droplet Deformation ◽  
Droplet Dynamics ◽  
Lattice Boltzmann Simulations

AbstractLattice Boltzmann simulations based on the Cahn-Hilliard diffuse interface approach are performed for droplet dynamics in viscous fluid under shear flow, where the degree of confinement between two parallel walls can play an important role. The effects of viscosity ratio, capillary number, Reynolds number, and confinement ratio on droplet deformation and break-up in moderately and highly confined shear flows are investigated.

scholarly journals Lattice Boltzmann simulations of drying suspensions of soft particles

2021 ◽  
Vol 379 (2208) ◽  
pp. 20200399 ◽  
Author(s):  
M. Wouters ◽  
O. Aouane ◽  
M. Sega ◽  
J. Harting
Keyword(s):  
Lattice Boltzmann ◽  
Colloidal Suspension ◽  
Dynamics Simulation ◽  
Drying Process ◽  
Rigid Particles ◽  
Lattice Boltzmann Simulations ◽  
Soft Particles ◽  
Formation Of Cracks ◽  
Small Clusters

The ordering of particles in the drying process of a colloidal suspension is crucial in determining the properties of the resulting film. For example, microscopic inhomogeneities can lead to the formation of cracks and defects that can deteriorate the quality of the film considerably. This type of problem is inherently multiscale and here we study it numerically, using our recently developed method for the simulation of soft polymeric capsules in multicomponent fluids. We focus on the effect of the particle softness on the film microstructure during the drying phase and how it relates to the formation of defects. We quantify the order of the particles by measuring both the Voronoi entropy and the isotropic order parameter. Surprisingly, both observables exhibit a non-monotonic behaviour when the softness of the particles is increased. We further investigate the correlation between the interparticle interaction and the change in the microstructure during the evaporation phase. We observe that the rigid particles form chain-like structures that tend to scatter into small clusters when the particle softness is increased. This article is part of the theme issue ‘Progress in mesoscale methods for fluid dynamics simulation’.

LATTICE-BOLTZMANN SIMULATIONS OF FLOW THROUGH NAFION POLYMER MEMBRANES

2003 ◽  
Vol 17 (01n02) ◽  
pp. 135-138 ◽  
Author(s):  
HIDEMITSU HAYASHI ◽  
SATORU YAMAMOTO ◽  
SHI-AKI HYODO
Keyword(s):  
Lattice Boltzmann ◽  
Dissipative Particle Dynamics ◽  
Three Dimensional ◽  
Polymer Membranes ◽  
Dynamics Simulation ◽  
Fluid Viscosity ◽  
Lattice Boltzmann Simulations ◽  
Flow Through ◽  
Boltzmann Method ◽  
Dissipative Particle Dynamics Simulation

Simulations of flow through three-dimensional porous structures of NAFION polymer membranes are performed with a Lattice-Boltzmann method (LBM) for incompressible fluid. Geometry data of NAFION are constructed from a result of a dissipative particle dynamics simulation for three values of the water content, 10%, 20%, and 30%, and are used as the geometry input for the LBM. Permeability of the porous structure is extracted from results of the LBM simulation using Darcy's low. The permeability K is shown to be expressed as K = L2 × Ktpl with a characteristic length L and the dimensionless permeability Ktpl depending only on the topological structure of the porous media. Dependence of Ktpl is examined on the pressure gradient, the fluid viscosity, and the resolution of the computational grid.

ON THE SYSTEM SIZE OF LATTICE BOLTZMANN SIMULATIONS

2004 ◽  
Vol 15 (08) ◽  
pp. 1049-1060 ◽  
Author(s):  
GUSZTÁV MAYER ◽  
GÁBOR HÁZI ◽  
JÓZSEF PÁLES ◽  
ATTILA R. IMRE ◽  
BJÖRN FISCHER ◽  
...  
Keyword(s):  
Lattice Boltzmann ◽  
Lattice Site ◽  
Finite Lattice ◽  
Continuous Distribution ◽  
System Size ◽  
Dynamics Simulation ◽  
Lattice Boltzmann Simulations ◽  
Initial Assumption ◽  
Boltzmann Method ◽  
Number Of Particles

In lattice Boltzmann simulations particle groups — represented by scalar velocity distributions — are moved on a finite lattice. The size of these particle groups is not well-defined although it is crucial to assume that they should be big enough for using a continuous distribution. Here we propose to use the liquid–vapor interface as an internal yardstick to scale the system. Comparison with existing experimental data and with molecular dynamics simulation of Lennard–Jones-argon shows that the number of atoms located on one lattice site is in the order of few atoms. This contradicts the initial assumption concerning the number of particles in the group, therefore seems to raise some doubts about the applicability of the lattice Boltzmann method in certain problems whenever interfaces play important role and ergodicity does not hold.

scholarly journals Lattice Boltzmann simulations of bubble formation in a microfluidic T-junction

2011 ◽  
Vol 369 (1945) ◽  
pp. 2405-2413 ◽  
Author(s):  
Luz Amaya-Bower ◽  
Taehun Lee
Keyword(s):  
Lattice Boltzmann ◽  
Formation Process ◽  
Viscosity Ratio ◽  
Bubble Formation ◽  
Diffuse Interface ◽  
Equilibrium Contact Angle ◽  
Systematic Analysis ◽  
System Transition ◽  
Lattice Boltzmann Simulations ◽  
Interface Theory

A lattice Boltzmann equation method based on the Cahn–Hilliard diffuse interface theory is developed to investigate the bubble formation process in a microchannel with T-junction mixing geometry. The bubble formation process has different regimes, namely, squeezing, dripping and jetting regimes, which correspond to the primary forces acting on the system. Transition from regime to regime is generally dictated by the capillary number Ca , volumetric flow ratio Q and viscosity ratio λ . A systematic analysis is performed to evaluate these effects. The computations are performed in the range of 10 −4 < Ca <1, 1< Q <20 and 10 −2 < λ <1, with the equilibrium contact angle varying from 30 °  to 150 ° .

scholarly journals Validation and application of the lattice Boltzmann algorithm for a turbulent immiscible Rayleigh–Taylor system

2021 ◽  
Vol 379 (2208) ◽  
pp. 20200396 ◽  
Author(s):  
H. S. Tavares ◽  
L. Biferale ◽  
M. Sbragaglia ◽  
A. A. Mailybaev
Keyword(s):  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Dynamics Simulation ◽  
Turbulent Regime ◽  
Theme Issue ◽  
Immiscible Flows ◽  
Late Stages ◽  
Kinetic And Potential Energies ◽  
Numerical Complexity

We develop a multicomponent lattice Boltzmann (LB) model for the two-dimensional Rayleigh–Taylor turbulence with a Shan–Chen pseudopotential implemented on GPUs. In the immiscible case, this method is able to accurately overcome the inherent numerical complexity caused by the complicated structure of the interface that appears in the fully developed turbulent regime. The accuracy of the LB model is tested both for early and late stages of instability. For the developed turbulent motion, we analyse the balance between different terms describing variations of the kinetic and potential energies. Then we analyse the role of the interface in the energy balance and also the effects of the vorticity induced by the interface in the energy dissipation. Statistical properties are compared for miscible and immiscible flows. Our results can also be considered as a first validation step to extend the application of LB model to three-dimensional immiscible Rayleigh-Taylor turbulence. This article is part of the theme issue ‘Progress in mesoscale methods for fluid dynamics simulation’.

Modeling Elastic Walls in Lattice Boltzmann Simulations of Arterial Blood Flow

2013 ◽  
Vol 23 (2) ◽  
Author(s):  
Xenia Descovich ◽  
Giuseppe Pontrelli ◽  
Sauro Succi ◽  
Simone Melchionna ◽  
Manfred Bammer
Keyword(s):  
Blood Flow ◽  
Lattice Boltzmann ◽  
Arterial Blood Flow ◽  
Arterial Blood ◽  
Lattice Boltzmann Simulations ◽  
Elastic Walls

The Fluctuating Lattice Boltzmann

2018 ◽  
Author(s):  
Sauro Succi
Keyword(s):  
Brownian Motion ◽  
Fluid Flow ◽  
Lattice Boltzmann ◽  
Thermal Fluctuations ◽  
Directed Motion ◽  
Statistical Fluctuations ◽  
Lattice Boltzmann Models ◽  
Motion Versus ◽  
The Way

Fluid flow at nanoscopic scales is characterized by the dominance of thermal fluctuations (Brownian motion) versus directed motion. Thus, at variance with Lattice Boltzmann models for macroscopic flows, where statistical fluctuations had to be eliminated as a major cause of inefficiency, at the nanoscale they have to be summoned back. This Chapter illustrates the “nemesis of the fluctuations” and describe the way they have been inserted back within the LB formalism. The result is one of the most active sectors of current Lattice Boltzmann research.

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