Modeling vorticity stretching of viscoelastic droplets during shearing flow

2021 ◽  
Vol 65 (6) ◽  
pp. 1327-1345
Author(s):  
Abdulwahab S. Almusallam ◽  
T. B. Bini
Keyword(s):  
Shearing Flow

Self-diffusion of bimodal suspensions of hydrodynamically interacting spherical particles in shearing flow

1994 ◽  
Vol 281 ◽  
pp. 51-80 ◽  
Author(s):  
Chingyi Chang ◽  
Robert L. Powell
Keyword(s):  
Diffusion Coefficients ◽  
Cluster Size ◽  
Near Field ◽  
Spherical Particles ◽  
Random Structure ◽  
Shearing Flow ◽  
Self Diffusion ◽  
Long Time ◽  
Mobility Matrix ◽  
Many Body Interactions

We study the average mobilities and long-time self-diffusion coefficients of a suspension of bimodally distributed spherical particles. Stokesian dynamics is used to calculate the particle trajectories for a monolayer of bimodal-sized spheres. Hydrodynamic forces only are considered and they are calculated using the inverse of the grand mobility matrix for far-field many-body interactions and lubrication formulae for near-field effects. We determine both the detailed microstructure (e.g. the pair-connectedness function and cluster formation) and the macroscopic properties (e.g. viscosity and self-diffusion coefficients). The flow of an ‘infinite’ suspension is simulated by considering 25, 49, 64 and 100 particles to be one ‘cell’ of a periodic array. Effects of both the size ratio and the relative fractions of the different-sized particles are examined. For the microstructures, the pair-connectedness function shows that the particles form clusters in simple shearing flow due to lubrication forces. The nearly symmetric angular structures imply the absence of normal stress differences for a suspension with purely hydrodynamic interactions between spheres. For average mobilities at infinite Péclet number, Ds0, our simulation results suggest that the reduction of Ds0 as concentration increases is directly linked to the influence of particle size distribution on the average cluster size. For long-time self-diffusion coefficients, Ds∞, we found good agreement between simulation and experiment (Leighton & Acrovos 1987 a; Phan and Leighton 1993) for monodispersed suspensions. For bimodal suspensions, the magnitude of Ds∞, and the time to reach the asymptotic diffusive behaviour depend on the cluster size formed in the system, or the viscosity of the suspension. We also consider the effect of the initial configuration by letting the spheres be both organized (size segregated) and randomly placed. We find that it takes a longer time for a suspension with an initially organized structure to achieve steady state than one with a random structure.

Effect of Shear Surface Boundaries on Stress for Shearing Flow of Dry Metal Powders—An Experimental Study

1987 ◽  
Vol 109 (2) ◽  
pp. 232-237 ◽  
Author(s):  
K. Craig ◽  
R. H. Buckholz ◽  
G. Domoto
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Normal Stress ◽  
Particle Diameter ◽  
Surface Boundary ◽  
Metal Powders ◽  
Shear Surface ◽  
Shear Cell ◽  
Shearing Flow ◽  
Solids Content

This paper studies the rapid simple shearing flow of dry cohesionless metal powders contained between parallel rotating plates. In this study, an annular shear cell test apparatus was used; the dry metal powders are rapidly sheared by rotating one of the shear surfaces while the other shear surface remains fixed. Such a flow geometry is of interest to tribologists working in the area of dry or powder lubrication. The shear stress and normal stress on the stationary surface are measured as a function of the following parameters: shear surface boundary material and roughness, the shear-cell gap thickness, the shear-rate and the fractional solids content. Both the fractional solids content and the gap thickness are kept at prescribed values during stress measurements. In this experiment the metal powder tested is different from the shear transmission surface material; the effect on the measured normal and shear stress data are reported. The results show the dependence of the normal stress and the shear stress on the shear-rate, particle density and particle diameter. Likewise, a significant stress dependence on both the fractional solids content and the shear-cell gap thickness was observed.

scholarly journals Response of monoflagellate pullers to a shearing flow: A simulation study of microswimmer guidance

2018 ◽  
Vol 98 (6) ◽  
Author(s):  
Benjamin J. Walker ◽  
Kenta Ishimoto ◽  
Richard J. Wheeler ◽  
Eamonn A. Gaffney
Keyword(s):  
Simulation Study ◽  
Shearing Flow

Combined Steady and Oscillatory Shearing Flow of Oriented Fluids

1972 ◽  
Vol 56 (10) ◽  
pp. 5063-5071 ◽  
Author(s):  
P. N. Kaloni ◽  
G. C. W. Sabin
Keyword(s):  
Shearing Flow ◽  
Oscillatory Shearing

THE CONCOMITANT-EFFECT OF ELECTRORHEOLOGICAL FLUID IN A CONTROL FLOW FIELD

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1263-1269 ◽  
Author(s):  
Shi-sha ZHU ◽  
Toyohisa FUJITA ◽  
Qi-xin WANG ◽  
Kejun LIU ◽  
Gjergj DODBIBA
Keyword(s):  
Flow Field ◽  
Power Transmission ◽  
Electrorheological Fluid ◽  
Control Flow ◽  
Fluid Power ◽  
Control Technology ◽  
Capture Effect ◽  
Shearing Flow ◽  
Er Fluid ◽  
Research Show

The description of ER response in a flow field is a key issue in researching control technology of ER fluid. In this paper, an experimental work on controlling flow field in fluid power transmission has been carried out. The results of research show that the control flow field differs from the rotary shearing flow field in an experimental instrument. Besides the ER effect there is a concomitant-effect of ER response called "capture effect" in the field, which is unbeneficial to the control on fluid power transmission.

An exact solution for shearing flow of multicomponent mixtures

1991 ◽  
Vol 46 (9) ◽  
pp. 2331-2338 ◽  
Author(s):  
Stephen L. Passman ◽  
Donald A. Drew
Keyword(s):  
Exact Solution ◽  
Multicomponent Mixtures ◽  
Shearing Flow

Numerical Study of Stability and Accuracy of the Immersed Boundary Method Coupled to the Lattice Boltzmann BGK Model

2014 ◽  
Vol 16 (1) ◽  
pp. 136-168 ◽  
Author(s):  
Yongguang Cheng ◽  
Luoding Zhu ◽  
Chunze Zhang
Keyword(s):  
Lattice Boltzmann ◽  
Numerical Study ◽  
Rigid Wall ◽  
Segment Length ◽  
Immersed Boundary ◽  
Coupling Scheme ◽  
Circular Membrane ◽  
Shearing Flow ◽  
Dirac Delta ◽  
Forcing Term

AbstractThis paper aims to study the numerical features of a coupling scheme between the immersed boundary (IB) method and the lattice Boltzmann BGK (LBGK) model by four typical test problems: the relaxation of a circular membrane, the shearing flow induced by a moving fiber in the middle of a channel, the shearing flow near a non-slip rigid wall, and the circular Couette flow between two inversely rotating cylinders. The accuracy and robustness of the IB-LBGK coupling scheme, the performances of different discrete Dirac delta functions, the effect of iteration on the coupling scheme, the importance of the external forcing term treatment, the sensitivity of the coupling scheme to flow and boundary parameters, the velocity slip near non-slip rigid wall, and the origination of numerical instabilities are investigated in detail via the four test cases. It is found that the iteration in the coupling cycle can effectively improve stability, the introduction of a second-order forcing term in LBGK model is crucial, the discrete fiber segment length and the orientation of the fiber boundary obviously affect accuracy and stability, and the emergence of both temporal and spatial fluctuations of boundary parameters seems to be the indication of numerical instability. These elaborate results shed light on the nature of the coupling scheme and may benefit those who wish to use or improve the method.

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