MATHEMATICAL MODELING OF OSCILLATORY MAGNETO-CONVECTION OF A COUPLE-STRESS BIOFLUID IN AN INCLINED ROTATING CHANNEL

2012 ◽  
Vol 12 (03) ◽  
pp. 1250050 ◽  
Author(s):  
O. ANWAR BÉG ◽  
S. K. GHOSH ◽  
S. AHMED ◽  
TASVEER BÉG
Keyword(s):  
Secondary Flow ◽  
Couple Stress ◽  
Shear Stresses ◽  
Field Equations ◽  
Electrically Conducting ◽  
Stress Effects ◽  
Secondary Velocity ◽  
Unit Depth ◽  
Primary Velocity ◽  
Rotating Channel

A mathematical study is conducted of the oscillatory hydromagnetic flow of a viscous, incompressible, electrically conducting, non-Newtonian bio-fluid in an inclined, rotating channel with nonconducting walls, incorporating couple stress effects. The constitutive equations for a couple-stress fluid and the Maxwell electromagnetic field equations are presented and then reduced to a set of coupled partial differential equations for the primary and secondary flow. The model is then nondimensionalized with appropriate variables and shown to be controlled by the inverse Ekman number (K2= 1/Ek), the hydromagnetic body force parameter (M), channel inclination (α), Grashof number (Gr), Prandtl number (Pr), oscillation frequency (ω), and time variable (ωT). Analytical solutions are derived using complex variables. The influence of the governing parameters on the primary velocity (u), secondary velocity (w), temperature (θ), primary and secondary flow discharges per unit depth in the channel (Qx, Qz), and frictional shear stresses due to primary and secondary flow (τx, τz), are studied graphically and using tables. Applications of the study arise in the simulation of the manufacture of electrically conducting bio-polymeric liquids and magneto-physiological flow devices.

Mean flow structure in meanders of the Squamish River, British Columbia

1978 ◽  
Vol 15 (11) ◽  
pp. 1833-1849 ◽  
Author(s):  
Edward J. Hickin
Keyword(s):  
Velocity Field ◽  
Secondary Flow ◽  
Flow Structure ◽  
Maximum Velocity ◽  
Shear Stresses ◽  
Channel Migration ◽  
Mean Flow ◽  
Channel Form ◽  
Collapse Model ◽  
Primary Velocity

The primary velocity field and pattern of secondary flow are described for nine consecutive bends of the Squamish River in southwest British Columbia.The velocity field largely can be explained in terms of variation in channel form, advective acceleration responses, and water transfers by secondary flow.The pattern of secondary flow accords with the general model of spiral flow in meanders. Divergences from this ideal pattern can be explained by bend–flow interaction induced by the variable planform geometry of the channel.The strength of secondary circulation increases rapidly as the ratio of the radius of bend curvature to channel width (rm/w) declines from 4.0 to the data minimum of 1.41. There is no discontinuity phenomenon in the flow structure over the measured range of rm/w; the Bagnold separation–collapse model does not apply to the Squamish River.As rm/w declines to values less than 3.0, the maximum velocity filament shifts from the concave to the convex bank zone. The resulting high shear stresses over the point bar and declining shear stresses at the concave bank markedly reduce the channel migration rate.Separation zones developed at the concave bank of tightly curved bends provide the mechanism for completely halting (and indeed reversing) the process of channel migration.

scholarly journals Adomain computation of radiative-convective bi-directional stretching flow of a magnetic non-Newtonian fluid in porous media with homogeneous–heterogeneous reactions

2020 ◽  
Vol 34 (18) ◽  
pp. 2050165 ◽  
Author(s):  
S. R. Mishra ◽  
Md. Shamshuddin ◽  
O. Anwar Beg ◽  
A. Kadir
Keyword(s):  
Stretching Sheet ◽  
Heterogeneous Reactions ◽  
Sisko Fluid ◽  
Heterogeneous Chemical Reaction ◽  
Electrically Conducting ◽  
Heterogeneous Chemical ◽  
Permeability Parameter ◽  
Secondary Velocity ◽  
Primary Velocity ◽  
Power Law Index

In the present communication, the laminar, incompressible, hydromagnetic flow of an electrically conducting non-Newtonian (Sisko) fluid over a bi-directional stretching sheet in a porous medium is studied theoretically. Thermal radiation flux, homogeneous–heterogeneous chemical reactions and convective wall heating are included in the model. The resultant nonlinear ordinary differential equations with transformed boundary conditions via similarity transformation are then solved with the semi-analytical Adomain Decomposition Method (ADM). Validation with earlier studies is included for the nonradiative case. Extensive visualization of velocity, temperature and species concentration distributions for various emerging parameters is included. Increasing the magnetic field and inverse permeability parameter is observed to decelerate both the primary and secondary velocity magnitudes whereas they increase temperatures in the regime. Increasing sheet stretching ratio weakly accelerates the primary flow throughout the boundary layer whereas it more dramatically accelerates the secondary flow near sheet surface. Temperature is consistently reduced with increasing stretching sheet ratio whereas it is strongly enhanced with greater radiative parameter. With greater Sisko non-Newtonian power-law index the primary velocity and temperature are decreased whereas the secondary velocity is increased. Increasing both homogenous and heterogeneous chemical reaction parameters is found to weakly and more strongly, respectively, deplete concentration magnitudes whereas greater Schmidt number enhances them.

scholarly journals Flow of a Visco-Elastic Fluid Past a Porous Plate in a Rotating System

2013 ◽  
Vol 18 (1) ◽  
pp. 27-41
Author(s):  
M. Guria ◽  
R.N. Jana
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Secondary Flow ◽  
Porous Plate ◽  
Elastic Parameter ◽  
Rotation Parameter ◽  
Elastic Fluid ◽  
Uniform Suction ◽  
Secondary Velocity ◽  
Primary Velocity

An analysis is made on a steady flow of an incompressible visco-elastic fluid (of small memory) past a porous plate subject to uniform suction or blowing. The fluid and the plate rotate in unison with uniform angular velocity about an axis perpendicular to the plate. It is shown that for a visco-elastic fluid of small memory, a boundary layer is formed for uniform suction or blowing at the plate. It is found that the primary velocity increases whereas the secondary velocity increases near the plate and decreases away from the plate with an increase in the elastic parameter. The secondary flow shows flow reversal for a large elastic parameter. It is found that both primary and secondary velocities increase near the plate and decrease away from the plate with an increase in the rotation parameter. It is also found that the shear stress due to primary flow increases with an increase in either the elastic parameter or rotation parameter. On the other hand, the shear stress due to secondary flow decreases with an increase in the elastic parameter while it increases with an increase in the rotation parameter. The temperature distribution in the boundary layer is also determined. It is shown that elasticity leads to an increase in heat transfer at the plate.

scholarly journals Rotating Hydromagnetic Two-Fluid Convective Flow and Temperature Distribution in an Inclined Channel

2018 ◽  
Vol 7 (4.10) ◽  
pp. 629
Author(s):  
P. Sri Ramachandra Murty ◽  
G. Balaji Prakash ◽  
Ch. Karuna Sree
Keyword(s):  
Magnetic Field ◽  
Temperature Distribution ◽  
Convective Flow ◽  
The Other ◽  
Parallel Plates ◽  
Inclined Channel ◽  
Electrically Conducting ◽  
Secondary Velocity ◽  
Primary Velocity ◽  
Two Fluid

Magnetohydrodynamic convective two-fluid flow and temperature distribution between two inclined parallel plates in which one fluid being electrically non-conducting and the other fluid is electrically conducting is studied. A constant magnetic field is applied normal to the flow. The system is rotated about y-axis with an angular velocity ‘W’.  Perturbation method is used to obtain solutions for primary velocity, secondary velocity and temperature distribution by assuming that the fluids in the two regions are incompressible, laminar, steady  and  fully  developed.  Increasing  values  of  rotation  is  to  reduce  temperature  distribution  and  primary  velocity where as thesecondary velocity increases for smaller rotation, while for larger rotation it decreases. 

scholarly journals Studying dynamic stress effects on the behaviour of THP-1 cells by microfluidic channels

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Semra Zuhal Birol ◽  
Rana Fucucuoglu ◽  
Sertac Cadirci ◽  
Ayca Sayi-Yazgan ◽  
Levent Trabzon
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Vascular System ◽  
Circulatory System ◽  
Disease Process ◽  
Microfluidic Channels ◽  
Shear Stresses ◽  
Stress Effects ◽  
Adhesion Behavior ◽  
Cycling System

AbstractAtherosclerosis is a long-term disease process of the vascular system that is characterized by the formation of atherosclerotic plaques, which are inflammatory regions on medium and large-sized arteries. There are many factors contributing to plaque formation, such as changes in shear stress levels, rupture of endothelial cells, accumulation of lipids, and recruitment of leukocytes. Shear stress is one of the main factors that regulates the homeostasis of the circulatory system; therefore, sudden and chronic changes in shear stress may cause severe pathological conditions. In this study, microfluidic channels with cavitations were designed to mimic the shape of the atherosclerotic blood vessel, where the shear stress and pressure difference depend on design of the microchannels. Changes in the inflammatory-related molecules ICAM-1 and IL-8 were investigated in THP-1 cells in response to applied shear stresses in an continuous cycling system through microfluidic channels with periodic cavitations. ICAM-1 mRNA expression and IL-8 release were analyzed by qRT-PCR and ELISA, respectively. Additionally, the adhesion behavior of sheared THP-1 cells to endothelial cells was examined by fluorescence microscopy. The results showed that 15 Pa shear stress significantly increases expression of ICAM-1 gene and IL-8 release in THP-1 cells, whereas it decreases the adhesion between THP-1 cells and endothelial cells.

scholarly journals Incidence Angle and Pitch-Chord Effects on Secondary Flows Downstream of a Turbine Cascade

1992 ◽  
Author(s):  
A. Perdichizzi ◽  
V. Dossena
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Incidence Angle ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Pressure Probe ◽  
Turbine Cascade ◽  
Oil Flow ◽  
Secondary Velocity ◽  
Secondary Flow Field

This paper describes the results of an experimental investigation of the three-dimensional flow downstream of a linear turbine cascade at off-design conditions. The tests have been carried out for five incidence angles from −60 to +35 degrees, and for three pitch-chord ratios: s/c = 0.58,0.73,0.87. Data include blade pressure distributions, oil flow visualizations, and pressure probe measurements. The secondary flow field has been obtained by traversing a miniature five hole probe in a plane located at 50% of an axial chord downstream of the trailing edge. The distributions of local energy loss coefficients, together with vorticity and secondary velocity plots show in detail how much the secondary flow field is modified both by incidence and cascade solidity variations. The level of secondary vorticity and the intensity of the crossflow at the endwall have been found to be strictly related to the blade loading occurring in the blade entrance region. Heavy changes occur in the spanwise distributions of the pitch averaged loss and of the deviation angle, when incidence or pitch-chord ratio is varied.

scholarly journals Three-dimensional oscillating flow between two parallel plates through a porous medium

2013 ◽  
Vol 18 (4) ◽  
pp. 1025-1037
Author(s):  
M. Guria ◽  
N. Ghara ◽  
R.N. Jana
Keyword(s):  
Reynolds Number ◽  
Porous Medium ◽  
Perturbation Technique ◽  
Three Dimensional ◽  
Injection Velocity ◽  
Parallel Plates ◽  
Suction Parameter ◽  
Constant Suction ◽  
Secondary Velocity ◽  
Primary Velocity

Abstract An unsteady Couette flow between two parallel plates when upper plates oscillates in its own plane and is subjected to a constant suction and the lower plate to a injection velocity distribution through the porous medium has been analyzed. The approximate solution has been obtained using perturbation technique. It is seen that the primary velocity increases whereas the secondary velocity decreases with an increase in permeability parameter. It is also found that the primary velocity increases with an increase in the Reynolds number as well as the suction parameter. The magnitude of the secondary velocity increases near the stationary plate but decreases near the oscillating plate with an increase in the Reynolds number. Whereas, it increases with an increase in the suction parameter.

scholarly journals Unsteady Heat and Mass Transfer of Chemically Reacting Micropolar Fluid in a Porous Channel with Hall and Ion Slip Currents

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Odelu Ojjela ◽  
N. Naresh Kumar
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Chemical Reaction ◽  
Micropolar Fluid ◽  
Parallel Plates ◽  
Field Equations ◽  
Electrically Conducting ◽  
Similarity Transformations ◽  
Ion Slip ◽  
Chemically Reacting

This paper presents an incompressible two-dimensional heat and mass transfer of an electrically conducting micropolar fluid flow in a porous medium between two parallel plates with chemical reaction, Hall and ion slip effects. Let there be periodic injection or suction at the lower and upper plates and the nonuniform temperature and concentration at the plates are varying periodically with time. The flow field equations are reduced to nonlinear ordinary differential equations using similarity transformations and then solved numerically by quasilinearization technique. The profiles of velocity components, microrotation, temperature distribution and concentration are studied for different values of fluid and geometric parameters such as Hartmann number, Hall and ion slip parameters, inverse Darcy parameter, Prandtl number, Schmidt number, and chemical reaction rate and shown in the form of graphs.

Porous exponential slider bearings lubricated with MHD-couple stress fluid

2018 ◽  
Vol 70 (5) ◽  
pp. 838-845 ◽  
Author(s):  
N.B. Naduvinamani ◽  
Shridevi S. Hosmani
Keyword(s):  
Couple Stress ◽  
Numerical Solutions ◽  
Transverse Magnetic ◽  
Operating Conditions ◽  
Couple Stress Fluid ◽  
Content Type ◽  
Electrically Conducting ◽  
Slider Bearings ◽  
Load Carrying ◽  
First Time

Purpose The purpose of this study is to examine the magneto-hydrodynamic (MHD) effect on porous exponential slider bearings lubricated with couple stress fluid and to derive the modified Reynolds’s equation for non-Newtonian fluid under various operating conditions to obtain the optimum bearing parameters. Design/methodology/approach Based upon the MHD theory and Stokes theory for couple stress fluid, the governing equations relevant to the problem under consideration are derived. This paper analyzes the effect on porous exponential slider bearings with an electrically conducting fluid in the presence of a transverse magnetic field. Semi-numerical solutions are obtained and discussed. Findings It is found that there is an increase in the load carrying capacity, frictional force and decrease in the co-efficient of friction in porous bearings due to the presence of magnetic effects with couple stress fluid. Originality/value This study is relatively original and gives the MHD effect on porous exponential slider bearings lubricated with couple stress fluid. The author believes that the paper presents these results for the first time.

Unsteady Flow of Couple Stress Fluid Sandwiched Between Newtonian Fluids Through a Channel

2018 ◽  
Vol 73 (7) ◽  
pp. 629-637
Author(s):  
M. Devakar ◽  
Ankush Raje ◽  
Shubham Hande
Keyword(s):  
Unsteady Flow ◽  
Flow Rate ◽  
Couple Stress ◽  
Volume Flow Rate ◽  
Volume Flow ◽  
Newtonian Fluids ◽  
Couple Stress Fluid ◽  
Shear Stresses ◽  
Fluid Velocities ◽  
Fluid Parameters

AbstractThe aim of this article is to study the unsteady flow of immiscible couple stress fluid sandwiched between Newtonian fluids through a horizontal channel. The fluids and plates are initially at rest. At an instant of time, a constant pressure gradient is applied along the horizontal direction to generate the flow. The time-dependent partial differential equations are solved numerically using the finite difference method. The continuity of velocities and shear stresses at the fluid-fluid interfaces has been considered. The obtained results are displayed through graphs and are discussed for various fluid parameters pertaining the flow. The volume flow rate is also obtained numerically for diverse fluid parameters and is presented through a table. It is noticed that fluid velocities increased with time and reached a steady state after a certain time level. Also, the presence of couple stresses reduced the fluid velocities. Volume flow rate increased with Reynolds number and is reduced by increase of ratio of viscosities.

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