Induced-charge electro-osmotic flow around cylinders with various orientations

2016 ◽  
Vol 231 (21) ◽  
pp. 4057-4066 ◽  
Author(s):  
Cetin Canpolat
Keyword(s):  
Electric Fields ◽  
Double Layers ◽  
Cylinder Surface ◽  
Osmotic Flow ◽  
Ac Electric Fields ◽  
Velocity Magnitude ◽  
Electro Osmosis ◽  
Microparticle Image Velocimetry ◽  
Induced Charge ◽  
Electro Osmotic Flow

Induced-charge electro-osmosis around multiple gold-coated stainless steel rods under various AC electric fields is investigated using the techniques of microparticle image velocimetry and numerical simulation. In this study, the results of interactions between induced electric double layers of two identical conductive cylinders on surrounding fluid are presented. The induced-charge electro-osmosis flow around multiple rods in touch and with one cylinder diameter gap reveals quadrupolar flow structures with four vortices. The induced-charge electro-osmotic flow structure and velocity magnitude also depend on the cylinder geometry and orientation. It is seen that four small vortices develop in the close region of cylinder surface for multiple rods with gap, while the other four large vortices are surrounding them. The distributions of vorticity patterns also strongly depend on cylinder orientation in the close region of cylinder surface.

Induced-Charge Electroosmosis Around Touching Metal Rods

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Cetin Canpolat ◽  
Mingkan Zhang ◽  
William Rosen ◽  
Shizhi Qian ◽  
Ali Beskok
Keyword(s):  
Electric Fields ◽  
Radial Distance ◽  
Flow Structures ◽  
Weakly Nonlinear ◽  
Ac Electric Fields ◽  
Velocity Magnitude ◽  
Micro Piv ◽  
Image Velocimetry ◽  
Microparticle Image Velocimetry ◽  
Induced Charge

Induced-charge electroosmosis (ICEO) around multiple gold-coated stainless steel rods under different ac electric fields is analyzed using microparticle image velocimetry (micro-PIV) and numerical simulations. In the present investigation, the induced electric double layer (EDL) is in weakly nonlinear limit. The ICEO flow around multiple touching rods exhibits geometry dependent quadrupolar flow structures with four vortices. The velocity magnitude is proportional to the square of the electric field. The ICEO flow velocity also depends on the cylinder orientation. The velocity increases with increased radial distance from the rod’s surface, attains a maximum, and then decays to zero. Experimental and numerical velocity distributions have the same trend beyond 0.2 mm of the rod’s surface.

scholarly journals Dipolophoresis and Travelling-Wave Dipolophoresis of Metal Microparticles

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 259
Author(s):  
Jose Eladio Flores-Mena ◽  
Pablo García-Sánchez ◽  
Antonio Ramos
Keyword(s):  
Electric Fields ◽  
Particle Motion ◽  
Numerical Solutions ◽  
Particle Surface ◽  
Travelling Wave ◽  
Aqueous Electrolytes ◽  
Small Particles ◽  
Ac Electric Fields ◽  
Induced Charge ◽  
Analytical Expressions

We study theoretically and numerically the electrokinetic behavior of metal microparticles immersed in aqueous electrolytes. We consider small particles subjected to non-homogeneous ac electric fields and we describe their motion as arising from the combination of electrical forces (dielectrophoresis) and the electroosmotic flows on the particle surface (induced-charge electrophoresis). The net particle motion is known as dipolophoresis. We also study the particle motion induced by travelling electric fields. We find analytical expressions for the dielectrophoresis and induced-charge electrophoresis of metal spheres and we compare them with numerical solutions. This validates our numerical method, which we also use to study the dipolophoresis of metal cylinders.

scholarly journals Suppression of ion conductance by electro-osmotic flow in nano-channels with weakly overlapping electrical double layers

AIP Advances ◽  
2016 ◽  
Vol 6 (8) ◽  
pp. 085022 ◽  
Author(s):  
Yang Liu ◽  
Lingzi Guo ◽  
Xin Zhu ◽  
Qiushi Ran ◽  
Robert Dutton
Keyword(s):  
Double Layers ◽  
Ion Conductance ◽  
Osmotic Flow ◽  
Electrical Double Layers ◽  
Electro Osmotic Flow

scholarly journals Modeling of an AC-Electro-Osmosis Based Microfluidic Mixer

2017 ◽  
Author(s):  
H. Dilara Uslu ◽  
Çetin Canpolat ◽  
Barbaros Çetin
Keyword(s):  
Electric Fields ◽  
Comsol Multiphysics ◽  
Governing Equations ◽  
Ac Electroosmosis ◽  
Flow Rates ◽  
Microfluidic Mixer ◽  
Mixing Performance ◽  
Electro Osmosis ◽  
Micro Mixer ◽  
Electro Osmotic Flow

The purpose of this study is presenting an active micro-mixer, which is based on AC electro-osmotic flow driven on 3D micro wires. In order to solve governing equations of AC electroosmosis, a commercial software COMSOL Multiphysics® is implemented. Different wire configurations with various imposed electric fields and flow rates are tested for evaluating mixing efficiencies. The analyses show that mixing performance is significantly improved by number of the wires as well as wire orientation. It is also revealed that the degree of mixing can also be controlled by the tuning of the applied voltage for a given flow rate.

scholarly journals Effects of electric charge on osmotic flow across periodically arranged circular cylinders

2010 ◽  
Vol 664 ◽  
pp. 174-192 ◽  
Author(s):  
MASAKO SUGIHARA-SEKI ◽  
TAKESHI AKINAGA ◽  
TOMOAKI ITANO
Keyword(s):  
Surface Charge ◽  
Ion Concentration ◽  
Circular Cylinders ◽  
Double Layers ◽  
Cylinder Surface ◽  
Electrostatic Model ◽  
Surface Charges ◽  
Osmotic Flow ◽  
Endothelial Surface ◽  
Osmotic Reflection Coefficient

An electrostatic model is developed for osmotic flow across a layer consisting of identical circular cylinders with a fixed surface charge, aligned parallel to each other so as to form an ordered hexagonal arrangement. The expression of the osmotic reflection coefficient is derived for spherical solutes with a fixed surface charge suspended in an electrolyte, based on low-Reynolds-number hydrodynamics and a continuum, point-charge description of the electric double layers. The repulsive electrostatic interaction between the surface charges with the same sign on the solute and the cylinders is shown to increase the exclusion region of solute from the cylinder surface, which enhances the osmotic flow. Applying the present model to the study of osmotic flow across the endothelial surface glycocalyx of capillary walls has revealed that this electrostatic model could account well for the reflection coefficients measured for charged macromolecules, such as albumin, in the physiological range of charge density and ion concentration.

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