Limitations to the Growth Rate of Perturbation in Rotatory Convection in Couple-Stress Fluid in the presence of Magnetic Field

2017 ◽  
Vol 9 (1) ◽  
pp. 41
Author(s):  
Monika Khanna ◽  
Ajaib S. Banyal
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Couple Stress ◽  
Couple Stress Fluid

scholarly journals Influence of Boundary Roughness on Magnetohydrodynamic Kelvin-Helmholtz Instability in Couple-stress Fluid

2021 ◽  
Vol 88 (2) ◽  
pp. 93-105
Author(s):  
Priya M. Gouder ◽  
Praveen I. Chandaragi ◽  
Krishna B. Chavaraddi ◽  
G. B. Marali
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Couple Stress ◽  
Relative Velocity ◽  
Fluid Layer ◽  
Roughness Parameter ◽  
Couple Stress Fluid ◽  
Helmholtz Instability ◽  
The Impact ◽  
Boundary Roughness

The Kelvin-Helmholtz instability (KHI) occurs at the interface amongst two fluids, which are in relative motion with a common boundary. The growth rate of waves occurs whenever the relative velocity is greater as compared with the critical relative velocity. In the present paper, the influence of boundary roughness on KHI under the impact magnetic field in a couple-stress fluid layer bounded by a rigid surface at the lower side and upper side by a fluid saturated porous layer. Using suitable surface and boundary conditions, we have derived the dispersion relation and results are depicted graphically. As observed in presence of sharp interface, magnetic field exhibits stabilizing effect however, destabilizing effect is shown by the buoyancy force on KHI. Also, noted that the growth rate of interface reduces, as there is a rise in roughness parameter value.

On a Couple-Stress Fluid Heated from Below in a Porous Medium in the Presence of a Magnetic Field and Rotation

2002 ◽  
Vol 5 (2) ◽  
pp. 10 ◽  
Author(s):  
Sunil ◽  
R. C. Sharma ◽  
Mohinder Pal
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Couple Stress ◽  
Couple Stress Fluid

scholarly journals Magneto-rotatory compressible couple-stress fluid heated from below in porous medium

2016 ◽  
Vol 38 (1) ◽  
pp. 55-63
Author(s):  
Chander Bhan Mehta
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Couple Stress ◽  
Normal Modes ◽  
Sufficient Conditions ◽  
Couple Stress Fluid ◽  
Onset Of Convection ◽  
Medium Permeability ◽  
Effects Of Rotation ◽  
The Magnetic Field

Abstract The study is aimed at analysing thermal convection in a compressible couple stress fluid in a porous medium in the presence of rotation and magnetic field. After linearizing the relevant equations, the perturbation equations are analysed in terms of normal modes. A dispersion relation governing the effects of rotation, magnetic field, couple stress parameter and medium permeability have been examined. For a stationary convection, the rotation postpones the onset of convection in a couple stress fluid heated from below in a porous medium in the presence of a magnetic field. Whereas, the magnetic field and couple stress postpones and hastens the onset of convection in the presence of rotation and the medium permeability hastens and postpones the onset of convection with conditions on Taylor number. Further the oscillatory modes are introduced due to the presence of rotation and the magnetic field which were non-existent in their absence, and hence the principle of exchange stands valid. The sufficient conditions for nonexistence of over stability are also obtained.

Double-Diffusive Magneto Convection in a Compressible Couple-Stress Fluid Through Porous Medium

2011 ◽  
Vol 66 (5) ◽  
pp. 304-310 ◽  
Author(s):  
Pardeep Kumar ◽  
Hari Mohan
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Couple Stress ◽  
Mode Analysis ◽  
Couple Stress Fluid ◽  
Onset Of Convection ◽  
Linearized Stability ◽  
Medium Permeability ◽  
Solute Gradient ◽  
Double Diffusive

The double-diffusive convection in a compressible couple-stress fluid layer heated and soluted from below through porous medium is considered in the presence of a uniform vertical magnetic field. Following the linearized stability theory and normal mode analysis, the dispersion relation is obtained. For stationary convection, the compressibility, stable solute gradient, magnetic field, and couple-stress postpone the onset of convection whereas medium permeability hastens the onset of convection. Graphs have been plotted by giving numerical values to the parameters to depict the stability characteristics. The stable solute gradient and magnetic field introduce oscillatory modes in the system, which were non-existent in their absence. A condition for the system to be stable is obtained by using the Rayleigh-Ritz inequality. The sufficient conditions for the non-existence of overstability are also obtained.

Effects of Mixed Convection on the Oscillatory Flow of a Couple Stress Fluid through a Vertical Plate with Variable Fluid Properties

2018 ◽  
Vol 388 ◽  
pp. 328-343
Author(s):  
R. Suresh Babu ◽  
B. Rushi Kumar ◽  
P.A. Dinesh
Keyword(s):  
Magnetic Field ◽  
Couple Stress ◽  
Vertical Plate ◽  
Couple Stress Fluid ◽  
Electrically Conducting ◽  
Coupled Equations ◽  
Variable Permeability ◽  
Variable Fluid Properties ◽  
Fluid Properties ◽  
Dimensional Parameters

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.

scholarly journals Impact of nanofluids and magnetic field on the peristaltic transport of a couple stress fluid in an asymmetric channel with different wave forms

2020 ◽  
Vol 24 (2 Part B) ◽  
pp. 1407-1422
Author(s):  
Safia Akram ◽  
Farkhanda Afzal ◽  
Qamar Afzal
Keyword(s):  
Magnetic Field ◽  
Couple Stress ◽  
Peristaltic Flow ◽  
Couple Stress Fluid ◽  
Physical Parameters ◽  
Asymmetric Channel ◽  
Nanoparticle Concentration ◽  
Long Wavelength ◽  
Wave Forms ◽  
Linear Differential

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.

scholarly journals Magnetized couple stress fluid flow past a vertical cylinder under thermal radiation and viscous dissipation effects

2021 ◽  
Vol 10 (1) ◽  
pp. 343-362
Author(s):  
Suresha Suraiah Palaiah ◽  
Hussain Basha ◽  
Gudala Janardhana Reddy
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Fluid Flow ◽  
Thermal Radiation ◽  
Chemical Reaction ◽  
Couple Stress ◽  
Chemical Engineering ◽  
Polymer Processing ◽  
Couple Stress Fluid ◽  
Radiation Chemical

Abstract Contemporary investigation studies the silent features of the dissipative free convection couple stress fluid flow over a cylinder under the action of magnetic field, thermal radiation and porous medium with chemical reaction effect. Present two-dimensional viscous incompressible physical model is designed based on the considered flow geometry. Present physical problem gives the highly complicated nonlinear coupled partial differential equations (PDE's) which are not amenable to any of the known techniques. Thus, unconditionally stable, most accurate and speed converging with flexible finite difference implicit technique is utilized to simplify the dimensionless flow field equations. It is apparent from the current results that; the velocity profiles are diminished with enhancing values of magnetic field. Temperature profile increases with enhancing values of thermal radiation parameter. Velocity contours deviates away from the wall with enhancing magnetic parameter. Also, the effects of magnetic field, porous medium, thermal radiation, chemical reaction, buoyancy ratio parameter and Eckert number on couple stress flow velocity, temperature, and concentration profiles are studied. However, the present study has good number of applications in the various fields of engineering such as; polymer processing, solidification of liquid crystals, colloidal solutions, synovial joints, geophysics, chemical engineering, astrophysics and nuclear reactors etc. Finally, the current solutions are validated with the available results in the literature review and found to be in good agreement.

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