EFFECT OF COUPLE STRESSES ON ELECTROKINETIC OSCILLATORY FLOW OF BLOOD IN THE MICROCIRCULATORY SYSTEM

2018 ◽  
Vol 18 (03) ◽  
pp. 1850035 ◽  
Author(s):  
J. C. MISRA ◽  
S. CHANDRA
Keyword(s):  
Mathematical Model ◽  
Reynolds Number ◽  
Electric Field ◽  
Couple Stress ◽  
Electroosmotic Flow ◽  
Oscillatory Flow ◽  
Stress Effect ◽  
Computational Results ◽  
Ac Electric Field ◽  
Microcirculatory System

Of concern in the paper is the development of a mathematical model of blood flow in the microcirculatory system. The study pertains to a situation, where the system is subject to the action of an external AC electric field and the flow is oscillatory. The general case when the frequency of the electric field is different from that of the flow has been studied. Blood is treated as a couple stress fluid. The flow is supposed to take place between two oscillatory plates and is considered to be of electro-osmotic type. Our study is aimed at examining the effect of couple stress at different frequencies of the capillary wall and the applied AC electric field on electroosmotic flow of blood. The computational results indicate very clearly that the electrokinetic velocity of blood reduces as the couple stress effect increases and that the velocity reduces, when the Reynolds number rises. The results of the present study will serve as a reasonably good estimate for electro-osmotic transport of blood in small blood vessels.

Time- and Frequency- Domain Analysis of Transient Electroosmotic Flow Induced by Sinusoidal AC Electric Field in a Curved Microtube

2005 ◽  
Author(s):  
Win-Jet Luo ◽  
Jia-Kun Chen ◽  
Ruey-Jen Yang
Keyword(s):  
Phase Shift ◽  
Electric Field ◽  
Transient Response ◽  
Time Domain ◽  
Electroosmotic Flow ◽  
Sustained Oscillation ◽  
Sustained Oscillations ◽  
Ac Electric Field ◽  
Velocity Response ◽  
The Time Domain

A backwards-Euler time-stepping numerical method is applied to simulate the transient response of electroosmotic flow in a curved microtube. The velocity responses of the flow fields induced by applied sinusoidal AC electric fields of different frequencies are investigated. The transient response of the system is fundamentally important since both the amplitude and the time duration of the transient response must be maintained within tolerable or prescribed limits. When a sinusoidal AC electric field is applied, the transient response of the output velocity oscillates in the time-domain. However, after a certain settling time, the output velocity attains a sustained oscillation with the same amplitude as the driving field. In this study, the transient response of the electroosmotic flow is characterized by the time taken by the velocity response to reach the first peak, the peak of the sustained oscillation, the maximum overshoot, the settling time, and the bandwidth of the sustained oscillations in the time-domain. Meanwhile, the performance of the system is identified by plotting the output velocity response and the output velocity phase-shift against the frequency of the applied signal. A finite time is required for the momentum to diffuse fully from the walls to the center of the curved microtube cross-section. As the applied frequency is increased, the maximum overshoot and the bandwidth and peak of the sustained oscillations gradually decrease since insufficient time exists for the momentum to diffuse fully to the center of the microtube. Additionally, the phase-shift between the applied electric field and the output velocity response gradually increases as the frequency of the applied signal is increased.

Electro-osmotically actuated oscillatory flow of a physiological fluid on a porous microchannel subject to an external AC electric field having dissimilar frequencies

Open Physics ◽  
2014 ◽  
Vol 12 (4) ◽  
Author(s):  
Jagadis Misra ◽  
Sukumar Chandra
Keyword(s):  
Electric Field ◽  
Oscillatory Flow ◽  
Second Order ◽  
Partial Differential ◽  
Osmotic Flow ◽  
Micro Particles ◽  
Ac Electric Field ◽  
Fluidic Devices ◽  
Physiological Fluid ◽  
Electro Osmotic Flow

AbstractElectro-osmotic flow of a physiological fluid with prominent micropolar characteristics, flowing over a microchannel has been analyzed for a situation, where the system is subject to the action of an external AC electric field. In order to account for the rotation of the micro-particles suspended in the physiological fluid, the fluid has been treated as a micropolar fluid. The microchannel is considered to be bounded by two porous plates executing oscillatory motion. Such motion of the plates will normally induce oscillatory flow of the fluid. The governing equations of the fluid include a second-order partial differential equation depicting Gauss’s law of electrical charge distributions and two other partial differential equations of second order that arise out of the laws of conservation of linear and angular momenta. These equations have been solved under the sole influence of electrokinetic forces, by using appropriate boundary conditions. This enabled us to determine explicit analytical expressions for the electro-osmotic velocity of the fluid and the microrotation of the suspended micro-particles. These expressions have been used to obtain numerical estimates of important physical variables associated with the oscillatory electro-osmotic flow of a blood sample inside a micro-bio-fluidic device. The numerical results presented in graphical form clearly indicate that the formation of an electrical double layer near the vicinity of the wall causes linear momentum to reduce. In contrast, the angular momentum increases with the enhancement of microrotation of the suspended microparticles. The study will find important applications in the validation of results of further experimental and numerical models pertaining to flow in micro-bio-fluidic devices. It will also be useful in the improvement of the design and construction of various micro-bio-fluidic devices.

An AC Dielectrophoretic Trap for Cellular Assembly

2013 ◽  
Author(s):  
Mohammad Robiul Hossan ◽  
Robert Dillon ◽  
Prashanta Dutta
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Immersed Boundary ◽  
Computational Domain ◽  
Point Dipole ◽  
Dielectrophoretic Force ◽  
Immersed Interface Method ◽  
Immersed Interface ◽  
Maxwell Stress Tensor ◽  
Ac Electric Field

A mathematical model and numerical techniques are proposed to study AC electric field induced cellular assembly in a microfluidic device. In the mathematical model, the Maxwell stress tensor is used to calculate the dielectrophoretic force acting on particles by considering the physical effect of particles in the computational domain. Thus, the proposed model eliminates the approximations used in point dipole methods for calculating dielectrophoretic force. The numerical method is based on hybrid immersed boundary-immersed interface methods. An immersed boundary method is used for the fluid equations and particle transport, while an immersed interface method is employed to obtain the AC electric field in a fluid media with suspended particles. For the immersed interface method, an iterative algorithm is developed to solve the complex Poisson equation using a real variable formulation. The decoupled algorithm for solving complex differential equations converges rapidly. The hybrid method is used to investigate the physics of AC dielectrophoresis in a cross-channel junction. The numerical results show that with proper design and appropriate selection of applied potential and frequency, global electric field minima can be obtained to facilitate multiple particle trapping by exploiting the mechanism of negative dielectrophoresis.

Microfluidic Flow Control Using Induced-Charge Electroosmosis

2008 ◽  
Author(s):  
Kendra V. Sharp ◽  
Scott M. Davison ◽  
Shahrzad H. Yazdi
Keyword(s):  
Electric Field ◽  
Electroosmotic Flow ◽  
Microfluidic Channel ◽  
Microfluidic System ◽  
Ac Electric Field ◽  
Microfluidic Flow ◽  
Or Groups ◽  
Dc Electric Field ◽  
Induced Charge ◽  
Fixed Region

Work with dc electrokinetics has demonstrated that is works well for bulk transport of fluid an particles. However, it is difficult to achieve control of individual or groups of particles. This paper investigate the use of induced-charge electroosmosis (ICEO) as a means of providing control over particles within bulk dc electroosmotic flow. ICEO flow develops when an electric double layer is induced by an applied electric field at the surface of a conducting object. Here conducting posts are positioned in a microfluidic channel and ICEO flow develops around them due to an applied ac electric field. A dc electric field is applied across the length of the channel to induce electroosmotic flow past the ICEO region. Around one arrangement of posts the ac and dc flow fields combine to produce a region of recirculation which could be useful for holding a particle or particles within a fixed region of the channel. An alternative arrangement of posts functions to focus the flow into the center of the channel. A numerical model of the system is developed and used to explore means of adapting the ICEO flows to many situations. A method for fabricating a microfluidic system for ICEO flows is presented.

scholarly journals Mixing Enhancement of Electroosmotic Flow in Microchannels under DC and AC Electric Field

2020 ◽  
Vol 13 (1) ◽  
pp. 79-88 ◽  
Author(s):  
S. Dong ◽  
P. F. Geng ◽  
D. Dong ◽  
C. X. Li ◽  
◽  
...  
Keyword(s):  
Electric Field ◽  
Electroosmotic Flow ◽  
Mixing Enhancement ◽  
Ac Electric Field

A MATHEMATICAL MODEL FOR BLOOD FLOW THROUGH INCLINED ARTERIES UNDER THE INFLUENCE OF INCLINED MAGNETIC FIELD

2012 ◽  
Vol 12 (03) ◽  
pp. 1250033 ◽  
Author(s):  
DHARMENDRA TRIPATHI
Keyword(s):  
Magnetic Field ◽  
Mathematical Model ◽  
Reynolds Number ◽  
Blood Flow ◽  
Couple Stress ◽  
Volume Flow Rate ◽  
Flow Characteristics ◽  
Physical Parameters ◽  
Inclined Magnetic Field ◽  
Flow Through

A mathematical model is developed to study the characteristics of blood flow through flexible inclined arteries under the influence of an inclined magnetic field. The blood is supposed to be couple stress fluid and the geometry of wall surface of inclined arteries is taken as peristaltic wave. The expressions for axial velocity, volume flow rate, pressure gradient and stream function are obtained under the assumptions of long wavelength and low Reynolds number. The effects of different physical parameters reflecting couple stress parameter, Hartmann number, Reynolds number, Froude number, inclination of channel and inclination of magnetic field on velocity profile, pressure and frictional force are discussed. The stream lines are drawn for various values of emerging parameters and the trapping phenomenon is discussed. The significant features of the blood flow characteristics are analyzed by plotting graphs and discussed numerically in detail.

Mathematical model to predict the characteristics of polarization in dielectric materials: The concept of piezoelectrcity and electrostriction

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Lead Zirconate Titanate ◽  
Dielectric Material ◽  
Strain Curve ◽  
Dielectric Materials ◽  
Lead Zirconate ◽  
Simulation Software ◽  
Constitutive Law ◽  
Basic Material

Model was developed for the prediction of polarization characteristics in a dielectric material exhibiting piezoelectricity and electrostriction based on mathematical equations and MATLAB computer simulation software. The model was developed based on equations of polarization and piezoelectric constitutive law and the functional coefficient of Lead Zirconate Titanate (PZT) crystal material used was 2.3×10-6 m (thickness), the model further allows the input of basic material and calculation of parameters of applied voltage levels, applied stress, pressure, dielectric material properties and so on, to generate the polarization curve, strain curve and the expected deformation change in the material length charts. The mathematical model revealed that an application of 5 volts across the terminals of a 2.3×10-6 m thick dielectric material (PZT) predicted a 1.95×10-9 m change in length of the material, which indicates piezoelectric properties. Both polarization and electric field curve as well as strain and voltage curve were also generated and the result revealed a linear proportionality of the compared parameters, indicating a resultant increase in the electric field yields higher polarization of the dielectric materials atmosphere.

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