Asymptotic Suction/Injection Flow Induced by a Uniform MHD Free Stream Couple Stress Fluid Over a Flat Plate

Author(s):  
Mustafa Türkyilmazoglu

Abstract A theoretical study on the asymptotic suction/injection magnetohydrodynamic flow as a result of a uniform free stream Couple stress fluid flowing over a flat surface is undertaken in the current study. It is targeted to obtain exact flow and temperature solutions representing the permeable Couple stress fluid flow. Analytical expressions are extracted to derive interesting engineering tools such as momentum layer thickness, thermal layer thickness, wall shear stress and heat transfer rate. The physical parameters leading to the existence of wall suction/injection solutions are determined with their thresholds. Momentum and thermal layer analysis from the present results clearly reveal how they are influenced by the presence of electrically conducting Couple stress fluid. Further flow studies of similar kind will certainly benefit from the presented formulae.

2020 ◽  
Vol 9 (1) ◽  
pp. 352-360
Author(s):  
P. Aparna ◽  
P. Padmaja ◽  
N. Pothanna ◽  
J.V. Ramana Murthy

AbstractThe study of oscillating flow of a Couple Stress fluid past a permeable sphere is considered. Analytical solution for the flow field in terms of stream function is obtained using modified Bessel functions. The formula for Drag acting on the sphere due external flow is evaluated. Pressure field for the flow region past and inside the sphere is obtained. Effects of physical parameters like couple stress parameter, permeability, frequency and geometric parameters on the drag due to internal and external flows are represented graphically. It is observed that the drag for viscous fluid flow will be less than the case of couple-stress fluid flow and hence couple stress fluids offer resistance for flow.


2018 ◽  
Vol 70 (5) ◽  
pp. 838-845 ◽  
Author(s):  
N.B. Naduvinamani ◽  
Shridevi S. Hosmani

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.


2018 ◽  
Vol 388 ◽  
pp. 328-343
Author(s):  
R. Suresh Babu ◽  
B. Rushi Kumar ◽  
P.A. Dinesh

A numerical computation has been carriedout for the steady, mixed convective, incompressible, viscous, electrically conducting couple stress fluid through a vertical plate with variable fluid properties in a porous medium. A uniform magnetic field is applied in the transverse direction and parallel to the vertical plate of the physical model and governing equations are derived for it."Using a suitable similarity transformation, governed PDE's are transformed into a set of ODE's which are highly non-linear coupled equations. An advanced Shooting technique is adopted to compute the variations of velocity, temperature, concentration in terms of non-dimensional parameters. Also physical interpretation of non-dimensional parameters like couple stress parameter magnetic field Prandtl number Schmidt number thermal conductivity and solutal diffusivity parameters are examined through plots for both variable permeability and uniform permeability."From the numerical results, an excellent agreement has been observed for the present results, as well as comparison is made between the present and the earlier works for a particular case of the problem.


2012 ◽  
Vol 67 (5) ◽  
pp. 217-224 ◽  
Author(s):  
Tasawar Hayat ◽  
Zahid Iqbal ◽  
Muhammad Qasim ◽  
Omar M. Aldossary

This investigation reports the boundary layer flow and heat transfer characteristics in a couple stress fluid flow over a continuos moving surface with a parallel free stream. The effects of heat generation in the presence of convective boundary conditions are also investigated. Series solutions for the velocity and temperature distributions are obtained by the homotopy analysis method (HAM). Convergence of obtained series solutions are analyzed. The results are obtained and discussed through graphs for physical parameters of interest.


2015 ◽  
Vol 15 (04) ◽  
pp. 1550042 ◽  
Author(s):  
S. HINA ◽  
M. MUSTAFA ◽  
T. HAYAT ◽  
A. ALSAEDI

Analysis is performed for the simultaneous effects of heat and mass transfer on the peristaltic transport of an electrically conducting couple-stress fluid in a compliant walls channel. The study may be useful in understanding the physiological flow of blood through micro-circulatory system in the presence of particle-size effect. Long wavelength and low Reynolds number aspects are taken into consideration. Exact solutions for stream function, temperature and concentration are derived. Impact of pertinent parameters like the couple-stress fluid parameter (γ), Hartman number (M), amplitude ratio (ϵ), elastic parameters (E1, E2, E3, E4, E5), Brinkman number (Br) and Schmidt number (Sc). It is observed that velocity and temperature distributions are greater for couple stress fluid when compared with the Newtonian fluid.


2011 ◽  
Vol 16 (4) ◽  
pp. 477-487 ◽  
Author(s):  
Darbhashayanam Srinivasacharya ◽  
Kolla Kaladhar

This paper presents the Hall and Ion-slip effects on electrically conducting couple stress fluid flow between two circular cylinders in the presence of a temperature dependent heat source. The governing non-linear partial differential equations are transformed into a system of ordinary differential equations using similarity transformations and then solved using homotopy analysis method (HAM). The effects of the magnetic parameter, Hall parameter, Ion-slip parameter and couple stress fluid parameter on velocity and  temperature are discussed and shown graphically.


2020 ◽  
Vol 24 (2 Part B) ◽  
pp. 1407-1422
Author(s):  
Safia Akram ◽  
Farkhanda Afzal ◽  
Qamar Afzal

The present article deals with the effects of nanoparticles and magnetic field on the peristaltic flow of a couple stress fluid in an asymmetric channel with different wave forms. Mathematical modelling for 2-D and two directional flows of a couple stress fluid along with nanofluid are first given and then simplified under the assumptions of long wavelength and low Reynolds number approximation. After invoking these approximations we get coupled non-linear differential equations. The exact solutions of temperature distribution, the nanoparticle concentration, velocity, stream function and pressure gradient are calculated. Finally graphical results of various physical parameters of interest are discussed to examine the behavior of flow quantities.


Author(s):  
M. Prasad Siddalinga ◽  
B. S. Shashikala

Nonlinear oberbeck convection of a couple stress fluid in a vertical porous channel in the presence of transverse magnetic field is investigated in this paper. Analytical solution is obtained using the perturbation technique for vanishing values of the buoyancy parameter. Numerical solution of the nonlinear governing equations is obtained using the finite difference technique to validate the results obtained from the analytical solutions. The influence of the physical parameters on the flow, such as couple stress parameter, Hartmann number, temperature parameter, porous parameter and buoyancy parameter are evaluated and presented graphically. A new approach is used to analyse the flow for strong, weak and comparable porosity cases. It is found that increase in porous parameter, couple stress parameter, Hartmann number and temperature parameters decrease the velocity considerably.Kathmandu University Journal of Science, Engineering and Technology Vol. 12, No. I, June, 2016, Page: 49-62


2012 ◽  
Vol 67 (5) ◽  
pp. 275-281
Author(s):  
Mahinder Singh ◽  
Pardeep Kumar

The effect of a uniform vertical magnetic field on thermosolutal convection in a layer of an electrically conducting couple-stress fluid heated and soluted from below is considered. For the case of stationary convection, the stable solute gradient, magnetic field, and couple-stress parameter have stabilizing effect on the system. It is also observed that a stable solute gradient and a magnetic field introduce oscillatory modes in the system, but in the absence of a stable solute gradient and a magnetic field, oscillatory modes are not allowed and the principle of exchange of stabilities is valid.


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