Hydromagnetic Fluctuating Flow of a Viscoelastic Fluid in a Porous Channel

2005 ◽  
Vol 74 (2) ◽  
pp. 177-180 ◽  
Author(s):  
Sushil Kumar Ghosh
Keyword(s):  
Viscoelastic Fluid ◽  
Hartmann Number ◽  
Cross Flow ◽  
Transverse Magnetic ◽  
Frequency Parameter ◽  
Time Dependent ◽  
Viscoelastic Parameter ◽  
Flow Reynolds Number ◽  
Number Frequency ◽  
Dependent Flow

An exact periodic solution for the time dependent flow of a viscoelastic fluid in the presence of transverse magnetic field is derived. It is assumed that on one plate the fluid is injected with certain velocity and that it is sucked off at the other plate with the same velocity. Both plates are oscillating with a known velocity in their own plane. A perturbation method has been employed by treating the viscoelastic parameter to be small. Effects of viscoelastic parameter, cross-flow Reynolds number, frequency parameter, and Hartmann number on the velocity as well as wall shear stress of the flow are discussed here with graphs.

TRANSIENT HYDROMAGNETIC FLOW OF A VISCOUS FLUID

2011 ◽  
Vol 25 (19) ◽  
pp. 2533-2542
Author(s):  
T. HAYAT ◽  
S. N. NEOSSI NGUETCHUE ◽  
F. M. MAHOMED
Keyword(s):  
Magnetic Field ◽  
Viscous Fluid ◽  
Infinite Plate ◽  
Transverse Magnetic ◽  
Time Dependent ◽  
Hydromagnetic Flow ◽  
Electrically Conducting ◽  
Dependent Flow ◽  
Arbitrary Velocity ◽  
Numerical Approaches

This investigation deals with the time-dependent flow of an incompressible viscous fluid bounded by an infinite plate. The fluid is electrically conducting under the influence of a transverse magnetic field. The plate moves with a time dependent velocity in its own plane. Both fluid and plate exhibit rigid body rotation with a constant angular velocity. The solutions for arbitrary velocity and magnetic field is presented through similarity and numerical approaches. It is found that rotation induces oscillations in the flow.

scholarly journals Experimental and Computational Study of the Unsteady Flow in a 1.5 Stage Axial Turbine With Emphasis on the Secondary Flow in the Second Stator

1998 ◽  
Author(s):  
Ralf E. Walraevens ◽  
Heinz E. Gallus ◽  
Alexander R. Jung ◽  
Jürgen F. Mayer ◽  
Heinz Stetter
Keyword(s):  
Unsteady Flow ◽  
Secondary Flow ◽  
Computational Study ◽  
Three Dimensional ◽  
Cross Flow ◽  
Axial Flow ◽  
Time Dependent ◽  
Flow Structures ◽  
Mean Flow ◽  
Dependent Flow

A study of the unsteady flow in an axial flow turbine stage with a second stator blade row is presented. The low aspect ratio blades give way to a highly three-dimensional flow which is dominated by secondary flow structures. Detailed steady and unsteady measurements throughout the machine and unsteady flow simulations which include all blade rows have been carried out. The presented results focus on the second stator flow. Secondary flow structures and their origins are identified and tracked on their way through the passage. The results of the time-dependent secondary velocity vectors as well as flow angles and Mach number distributions as perturbation from the time-mean flow field are shown in cross-flow sections and azimuthal cuts throughout the domain of the second stator. At each location the experimental and numerical results are compared and discussed. A good overall agreement in the time-dependent flow behaviour as well as in the secondary flow structures is stated.

Fluctuating Flow of a Viscoelastic Fluid in a Porous Channel

1979 ◽  
Vol 46 (1) ◽  
pp. 21-25 ◽  
Author(s):  
R. K. Bhatnagar
Keyword(s):  
Reynolds Number ◽  
Viscoelastic Fluid ◽  
Mass Flux ◽  
Constant Velocity ◽  
Frequency Parameter ◽  
Viscous Fluids ◽  
The Other ◽  
Phase Lag ◽  
Viscoelastic Parameter ◽  
Viscosity Parameter

The problem of flow of a viscoelastic fluid characterized by the well-known Rivlin-Ericksen constitutive equations is discussed, when such a fluid is driven by an unsteady pressure gradient in the region between two parallel porous plates. It is assumed that on one plate the fluid is injected with certain constant velocity and that it is sucked off at the other with the same velocity. The governing differential equations, which do not involve the cross-viscosity parameter, are solved using a pertubation scheme treating the viscoelastic parameter to be small. The behavior of instantaneous velocity profiles, and magnitude and the phase lag of mass flux, which depend on the injection Reynolds number, the frequency parameter, and the viscoelastic parameter are discussed for various values of these parameters. Some very interesting departures of these from the corresponding flow of classical viscous fluids are reported when one or both of the injection Reynolds number and frequency parameter are small or large.

Flow Mixing Enhancement from Balloon Pulsations in an Intravenous Oxygenator

2004 ◽  
Vol 127 (3) ◽  
pp. 400-415 ◽  
Author(s):  
Amador M. Guzmán ◽  
Rodrigo A. Escobar ◽  
Cristina H. Amon
Keyword(s):  
Numerical Simulations ◽  
Oxygen Transfer ◽  
Fiber Bundle ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Three Dimensional ◽  
Time Dependent ◽  
Fiber Placement ◽  
Flow Mixing ◽  
Dependent Flow

Computational investigations of flow mixing and oxygen transfer characteristics in an intravenous membrane oxygenator (IMO) are performed by direct numerical simulations of the conservation of mass, momentum, and species equations. Three-dimensional computational models are developed to investigate flow-mixing and oxygen-transfer characteristics for stationary and pulsating balloons, using the spectral element method. For a stationary balloon, the effect of the fiber placement within the fiber bundle and the number of fiber rings is investigated. In a pulsating balloon, the flow mixing characteristics are determined and the oxygen transfer rate is evaluated. For a stationary balloon, numerical simulations show two well-defined flow patterns that depend on the region of the IMO device. Successive increases of the Reynolds number raise the longitudinal velocity without creating secondary flow. This characteristic is not affected by staggered or non-staggered fiber placement within the fiber bundle. For a pulsating balloon, the flow mixing is enhanced by generating a three-dimensional time-dependent flow characterized by oscillatory radial, pulsatile longitudinal, and both oscillatory and random tangential velocities. This three-dimensional flow increases the flow mixing due to an active time-dependent secondary flow, particularly around the fibers. Analytical models show the fiber bundle placement effect on the pressure gradient and flow pattern. The oxygen transport from the fiber surface to the mean flow is due to a dominant radial diffusion mechanism, for the stationary balloon. The oxygen transfer rate reaches an asymptotic behavior at relatively low Reynolds numbers. For a pulsating balloon, the time-dependent oxygen-concentration field resembles the oscillatory and wavy nature of the time-dependent flow. Sherwood number evaluations demonstrate that balloon pulsations enhance the oxygen transfer rate, even for smaller flow rates.

scholarly journals Influence of Magnetic Field on the Peristaltic Flow of a Viscous Fluid through a Finite-Length Cylindrical Tube

2010 ◽  
Vol 7 (3) ◽  
pp. 169-176 ◽  
Author(s):  
S. K. Pandey ◽  
Dharmendra Tripathi
Keyword(s):  
Magnetic Field ◽  
Viscous Fluid ◽  
Transverse Magnetic Field ◽  
Finite Length ◽  
Flow Rate ◽  
Hartmann Number ◽  
Volume Flow Rate ◽  
Critical Value ◽  
Transverse Magnetic ◽  
Volume Flow

The paper presents an analytical investigation of the peristaltic transport of a viscous fluid under the influence of a magnetic field through a tube of finite length in a dimensionless form. The expressions of pressure gradient, volume flow rate, average volume flow rate and local wall shear stress have been obtained. The effects of the transverse magnetic field and electrical conductivity (i.e. the Hartmann number) on the mechanical efficiency of a peristaltic pump have also been studied. The reflux phenomenon is also investigated. It is concluded, on the basis of the pressure distribution along the tubular length and pumping efficiency, that if the transverse magnetic field and the electric conductivity increase, the pumping machinery exerts more pressure for pushing the fluid forward. There is a linear relation between the averaged flow rate and the pressure applied across one wavelength that can restrain the flow due to peristalsis. It is found that there is a particular value of the averaged flow rate corresponding to a particular pressure that does not depend on the Hartmann number. Naming these values ‘critical values’, it is concluded that the pressure required for checking the flow increases with the Hartmann number above the critical value and decreases with it below the critical value. It is also inferred that magneto-hydrodynamic parameters make the fluid more prone to flow reversal. The conclusion applied to oesophageal swallowing reveals that normal water is easier to swallow than saline water. The latter is more prone to flow reversal. A significant difference between the propagation of the integral and non-integral number of waves along the tube is that pressure peaks are identical in the former and different in the latter cases.

Radiation Effect on the Mixed Convection Flow of a Viscoelastic Fluid Along an Inclined Stretching Sheet

2012 ◽  
Vol 67 (3-4) ◽  
pp. 195-202 ◽  
Author(s):  
Muhammad Qasim ◽  
Tasawar Hayat ◽  
Saleem Obaidat
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Viscoelastic Fluid ◽  
Radiative Heat ◽  
Heat Transfer Analysis ◽  
Convection Flow ◽  
Viscoelastic Parameter ◽  
Homotopy Analysis ◽  
Rosseland Approximation ◽  
Momentum Boundary Layer

This study concentrates on the heat transfer analysis of the steady flow of viscoelastic fluid along an inclined stretching surface. Analysis has been carried out in the presence of thermal radiation and the Rosseland approximation is used to describe the radiative heat flux in the energy equation. The equations of continuity, momentum and energy are reduced into the system of governing differential equations and solved by homotopy analysis method (HAM). The velocity and temperature are illustrated through graphs. Exact and homotopy solutions are compared in a limiting sense. It is noticed that viscoelastic parameter decreases the velocity and boundary layer thickness. It is also observed that increasing values of viscoelastic parameter reduces the thickness of momentum boundary layer and increase the heat transfer rate. However, it is found that increasing the radiation parameter has the effect of decreasing the local Nusselt number

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