Effect of shear flow on the hydrodynamic drag force of a spherical particle near wall evaluated using optical tweezers and microfluidics

Soft Matter ◽  
2021 ◽  
Author(s):  
Lester Canque Geonzon ◽  
Motoyoshi Kobayashi ◽  
Yasuhisa Adachi
Keyword(s):  
Shear Flow ◽  
Spherical Particle ◽  
Optical Tweezers ◽  
Drag Force ◽  
Simple Shear ◽  
Microfluidic Channel ◽  
Hydrodynamic Drag ◽  
Simple Shear Flow ◽  
Near Wall

The hydrodynamic drag force on a spherical particle in shear flow near-wall is investigated using optical tweezers and microfluidics. Simple shear flow is applied using a microfluidic channel at different...

Particle motion near and inside an interface

2007 ◽  
Vol 575 ◽  
pp. 333-357 ◽  
Author(s):  
C. POZRIKIDIS
Keyword(s):  
Shear Flow ◽  
Spherical Particle ◽  
Simple Shear ◽  
Suspended Particle ◽  
Rotational Symmetry ◽  
Simple Shear Flow ◽  
One Dimensional ◽  
Angular Velocities ◽  
Freely Suspended ◽  
Dimensional Integral

The motion of a spherical particle near the interface between two immiscible viscous fluids undergoing simple shear flow is considered in the limit of small Reynolds and capillary numbers where the interface exhibits negligible deformation. Taking advantage of the rotational symmetry of the boundaries of the flow with respect to the axis that is normal to the interface and passes through the particle centre, the problem is formulated as a system of one-dimensional integral equations for the first Fourier coefficients of the unknown components of the traction and velocity along the particle and interface contours. The results document the particle translational and angular velocities, and reveal that the particle slips while rolling over the interface under the influence of a simple shear flow, for any viscosity ratio. In the second part of the investigation, the motion of an axisymmetric particle straddling a planar interface is considered. The results confirm a simple exact solution when a particle with top-down symmetry is immersed half-way in each fluid and translates parallel to the interface, reveal a similar simple solution for a particle that is held stationary in simple shear flow, and document the force and torque exerted on a spherical particle for more general arrangements. The onset of a non-integrable singularity of the traction at the contact line prohibits the computation of the translational and angular velocities of a freely suspended particle convected under the action of a shear flow.

Emulsification of particle loaded drops in simple shear flow

2015 ◽  
Vol 470 ◽  
pp. 179-187 ◽  
Author(s):  
Tobias Merkel ◽  
Julius Henne ◽  
Lena Hecht ◽  
Volker Gräf ◽  
Elke Walz ◽  
...  
Keyword(s):  
Shear Flow ◽  
Simple Shear ◽  
Simple Shear Flow

scholarly journals Do Protein Molecules Unfold in a Simple Shear Flow?

2006 ◽  
Vol 91 (9) ◽  
pp. 3415-3424 ◽  
Author(s):  
Juan Jaspe ◽  
Stephen J. Hagen
Keyword(s):  
Shear Flow ◽  
Simple Shear ◽  
Simple Shear Flow ◽  
Protein Molecules

Numerical study of electric field effects on the deformation of two-dimensional liquid drops in simple shear flow at arbitrary Reynolds number

2009 ◽  
Vol 626 ◽  
pp. 367-393 ◽  
Author(s):  
STEFAN MÄHLMANN ◽  
DEMETRIOS T. PAPAGEORGIOU
Keyword(s):  
Steady State ◽  
Shear Flow ◽  
Electric Field ◽  
Electric Fields ◽  
Simple Shear ◽  
Simple Shear Flow ◽  
Physical Parameters ◽  
Shear Stresses ◽  
Two Dimensional ◽  
Liquid Drops

The effect of an electric field on a periodic array of two-dimensional liquid drops suspended in simple shear flow is studied numerically. The shear is produced by moving the parallel walls of the channel containing the fluids at equal speeds but in opposite directions and an electric field is generated by imposing a constant voltage difference across the channel walls. The level set method is adapted to electrohydrodynamics problems that include a background flow in order to compute the effects of permittivity and conductivity differences between the two phases on the dynamics and drop configurations. The electric field introduces additional interfacial stresses at the drop interface and we perform extensive computations to assess the combined effects of electric fields, surface tension and inertia. Our computations for perfect dielectric systems indicate that the electric field increases the drop deformation to generate elongated drops at steady state, and at the same time alters the drop orientation by increasing alignment with the vertical, which is the direction of the underlying electric field. These phenomena are observed for a range of values of Reynolds and capillary numbers. Computations using the leaky dielectric model also indicate that for certain combinations of electric properties the drop can undergo enhanced alignment with the vertical or the horizontal, as compared to perfect dielectric systems. For cases of enhanced elongation and alignment with the vertical, the flow positions the droplets closer to the channel walls where they cause larger wall shear stresses. We also establish that a sufficiently strong electric field can be used to destabilize the flow in the sense that steady-state droplets that can exist in its absence for a set of physical parameters, become increasingly and indefinitely elongated until additional mechanisms can lead to rupture. It is suggested that electric fields can be used to enhance such phenomena.

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