scholarly journals Flow generated due to longitudinal and torsional oscillations of a circular cylinder with suction/injection in a micropolar fluid

2012 ◽  
Vol 43 (3) ◽  
pp. 339-356 ◽  
Author(s):  
Ramana Murthy Venkata Josyula ◽  
Nagaraju Gajjela ◽  
Muthu Poosnar
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Micropolar Fluid ◽  
Couple Stress ◽  
Porous Cylinder ◽  
Suction Parameter ◽  
Torsional Oscillations ◽  
Viscosity Parameter ◽  
Constant Suction ◽  
Incompressible Micropolar Fluid

The flow generated by performing longitudinal and torsional oscillations of a porous circular cylinder which is subjected to constant suction/injection at the surface of the porous cylinder is studied. A finite difference method is proposed to analyse the velocity components and micro-rotation components, in an infinite expanse of an incompressible micropolar fluid. The effects of cross viscosity parameter, couple stress parameter, Reynolds number and Gyration parameter on the axial and torsional velocity components and on the micro-rotation components are shown graphically. Drag force acting on the wall of the cylinder is derived and the effects of micropolar parameters and suction parameter on the drag are shown graphically.

scholarly journals MHD flow of longitudinal and torsional oscillations of a circular cylinder with suction in a couple stress fluid

2013 ◽  
Vol 18 (4) ◽  
pp. 1099-1114 ◽  
Author(s):  
G. Nagaraju ◽  
J.V. Ramana Murthy
Keyword(s):  
Circular Cylinder ◽  
Couple Stress ◽  
Magnetic Parameter ◽  
Mhd Flow ◽  
Couple Stress Fluid ◽  
Radial Magnetic Field ◽  
Suction Parameter ◽  
Torsional Oscillations ◽  
Electrically Conducting ◽  
Constant Suction

Abstract In this paper, we consider the flow an incompressible electrically conducting couple stress fluid generated by performing longitudinal and torsional oscillations of a porous circular cylinder subjected to constant suction/injection at the surface of the cylinder and in the presence of a radial magnetic field. A finite difference method is proposed to analyze the velocity components, in an infinite expansion of a couple stress fluid under vanishing couple stresses on the boundary. The effects of the magnetic parameter, couple stress parameter, Reynolds number, the ratio of couple stress viscosities parameter and suction parameter on velocity components and drag are discussed and shown graphically.

scholarly journals Unsteady flow of a micropolar fluid generated by a circular cylinder subject to longitudinal and torsional oscillations

2014 ◽  
Vol 41 (1) ◽  
pp. 71-91 ◽  
Author(s):  
G. Nagaraju ◽  
Murthy Ramana
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Unsteady Flow ◽  
Explicit Expression ◽  
Drag Force ◽  
Axial Velocity ◽  
Micropolar Fluid ◽  
Torsional Oscillations ◽  
Analytical Expressions ◽  
Coupling Number

The flow generated by a circular cylinder, performing longitudinal and torsional oscillations, in an infinite expanse of a micropolar fluid is studied. Analytical expressions for the velocity and micro rotation components are obtained using no slip and hyper stick conditions at the boundaries. The effects of coupling number; Reynolds number and gyration parameter on the transverse and axial velocity components are shown and explained graphically. Also explicit expression for the drag force acting on the wall of the cylinder is derived and the effects of pertinent parameters on the drag are shown graphically.

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.

Laminar Forced Convection From a Circular Cylinder Placed in a Micropolar Fluid

2006 ◽  
Vol 129 (3) ◽  
pp. 256-264 ◽  
Author(s):  
F. M. Mahfouz
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Prandtl Number ◽  
Drag Coefficient ◽  
Forced Convection ◽  
Vortex Shedding ◽  
Micropolar Fluid ◽  
Clear Trend ◽  
Thermal Fields ◽  
Laminar Forced Convection

In this paper laminar forced convection associated with the cross-flow of micropolar fluid over a horizontal heated circular cylinder is investigated. The conservation equations of mass, linear momentum, angular momentum and energy are solved to give the details of flow and thermal fields. The flow and thermal fields are mainly influenced by Reynolds number, Prandtl number and material parameters of micropolar fluid. The Reynolds number is considered up to 200 while the Prandtl number is fixed at 0.7. The dimensionless vortex viscosity is the only material parameter considered in this study and is selected in the range from 0 to 5. The study has shown that generally the mean heat transfer decreases as the vortex viscosity increases. The results have also shown that both the natural frequency of vortex shedding and the amplitude of oscillating lift force experience clear reduction as the vortex viscosity increases. Moreover, the study showed that there is a threshold value for vortex viscosity above which the flow over the cylinder never responds to perturbation and stays symmetric without vortex shedding. Regarding drag coefficient, the results have revealed that within the selected range of controlling parameters the drag coefficient does not show a clear trend as the vortex viscosity increases.

scholarly journals Natural Convection Flow of MHD Micropolar Fluid Along a Vertical Wavy Surface

2017 ◽  
Vol 65 (2) ◽  
pp. 91-96
Author(s):  
S Sultana ◽  
Nepal C Roy
Keyword(s):  
Nusselt Number ◽  
Natural Convection ◽  
Skin Friction ◽  
Micropolar Fluid ◽  
Couple Stress ◽  
Magnetic Parameter ◽  
Wavy Surface ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Viscosity Parameter

We study the boundary layer characteristics of natural convection flow of an electrically conducting micropolar fluid along a vertical wavy surface. The dimensionless governing equations have been solved numerically. Results are presented in terms of the local skin-friction coefficient, the local Nusselt number and the local couple stress with the variation of amplitude-wavelength ratio, magnetic parameter, vortex viscosity parameter and spin-gradient viscosity parameter. Due to increase of the amplitude wave-length ratio, the skin-friction and the couple stress are found to decrease whereas the Nusselt number increases. The skin friction and the couple stress increase but the Nusselt number decreases for increasing values of vortex viscosity parameter. In addition, when the spin-gradient viscosity is increased, the maximum values of the Nusselt number and the couple stress significantly increase but the skin-friction decreases. The magnetic parameter considerably reduces the skin-friction, Nusselt number and couple stress. Dhaka Univ. J. Sci. 65(2): 91-96, 2017 (July)

Low Reynolds number flow around and heat transfer from a heated circular cylinder

2010 ◽  
Vol 1 (1-2) ◽  
pp. 15-20 ◽  
Author(s):  
B. Bolló
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Low Reynolds Numbers ◽  
Reynolds Number Flow ◽  
Two Dimensional Flow ◽  
Number Flow ◽  
Low Reynolds ◽  
Increasing Temperature

Abstract The two-dimensional flow around a stationary heated circular cylinder at low Reynolds numbers of 50 < Re < 210 is investigated numerically using the FLUENT commercial software package. The dimensionless vortex shedding frequency (St) reduces with increasing temperature at a given Reynolds number. The effective temperature concept was used and St-Re data were successfully transformed to the St-Reeff curve. Comparisons include root-mean-square values of the lift coefficient and Nusselt number. The results agree well with available data in the literature.

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