Thermal Instability of Compressible Micropolar Fluid in the Presence of Suspended Particles

2012 ◽  
Vol 28 (2) ◽  
pp. 239-246 ◽  
Author(s):  
N. Rani ◽  
S. K. Tomar
Keyword(s):  
Dispersion Relation ◽  
Rayleigh Number ◽  
Micropolar Fluid ◽  
Thermal Instability ◽  
Fluid Layer ◽  
Suspended Particles ◽  
Stationary Convection ◽  
Presence And Absence ◽  
Number Curve

AbstractA problem of thermal instability of a compressible micropolar fluid layer heated from below in the presence of suspended particles has been investigated. Dispersion relation is derived and Rayleigh number curve is then plotted against the wavenumber at different values of compressibility parameter for a model example. Compressibility is found to be responsible to destabilize the system in the presence and absence of suspended particles for both stationary and over stationary convection.

scholarly journals Thermal instability of compressible Walters’ (Model B′) fluid in the presence of Hall currents and suspended particles

2011 ◽  
Vol 15 (2) ◽  
pp. 487-500 ◽  
Author(s):  
Urvashi Gupta ◽  
Parul Aggarwal
Keyword(s):  
Magnetic Field ◽  
Dispersion Relation ◽  
Thermal Instability ◽  
Normal Modes ◽  
Suspended Particles ◽  
Elastic Parameter ◽  
Stationary Convection ◽  
Electrically Conducting ◽  
Permissible Range ◽  
Rayleigh Numbers

Effect of Hall currents and suspended particles is considered on the hydromagnetic stability of a compressible, electrically conducting Walters? (Model B?) elastico-viscous fluid. After linearizing the relevant hydromagnetic equations, the perturbation equations are analyzed in terms of normal modes. A dispersion relation governing the effects of visco-elasticity, magnetic field, Hall currents and suspended particles is derived. It has been found that for stationary convection, the Walters? (Model B?) fluid behaves like an ordinary Newtonian fluid due to the vanishing of the visco-elastic parameter. The compressibility and magnetic field have a stabilizing effect on the system, as such their effect is to postpone the onset of thermal instability whereas Hall currents and suspended particles are found to hasten the onset of thermal instability for permissible range of values of various parameters. Also, the dispersion relation is analyzed numerically and the results shown graphically. The critical Rayleigh numbers and the wavenumbers of the associated disturbances for the onset of instability as stationary convection are obtained and the behavior of various parameters on critical thermal Rayleigh numbers has been depicted graphically. The visco-elasticity, suspended particles and Hall currents (hence magnetic field) introduce oscillatory modes in the system which were non-existent in their absence.

scholarly journals Double-Diffusive Magnetoconvection of a Dusty Micropolar Fluid Saturating a Porous Medium

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Parul Aggarwal ◽  
Urvashi Gupta
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Micropolar Fluid ◽  
Fluid Layer ◽  
Suspended Particle ◽  
Suspended Particles ◽  
Linear Stability Theory ◽  
Stationary Convection ◽  
Medium Permeability ◽  
Solute Gradient

The paper deals with the theoretical investigation of the effect of dust/suspended particles on a layer of electrically conducting micropolar fluid heated and dissolved from below in the presence of a uniform vertical magnetic field in a porous medium. The presence of coupling between thermosolutal and micropolar effects and magnetic field brings oscillatory motions in the system. A dispersion relation governing the effects of solute gradient, magnetic field, and suspended particles is obtained for a fluid layer contained between two free boundaries using linear stability theory and normal mode technique. Graphs have been plotted by giving numerical values to various parameters involved to depict the stability characteristics for both cases of stationary convection and overstability. It has been found that, for permissible values of various parameters under consideration, the effect of magnetic field and solute gradient is stabilizing and that of medium permeability, suspended particles, and micropolar coefficient is destabilizing. Further it is found that the Rayleigh number for overstability is always less than that for stationary convection except for high values of suspended particle factor.

scholarly journals Effects of Suction–Injection–Combination (SIC) on the onset of Rayleigh–Bénard Electroconvection in a Micropolar Fluid

2015 ◽  
Vol 14 (3) ◽  
pp. 23-42 ◽  
Author(s):  
S Pranesh ◽  
Tarannum Sameena ◽  
Baby Riya
Keyword(s):  
Stability Analysis ◽  
Micropolar Fluid ◽  
Fluid Layer ◽  
Suspended Particles ◽  
Wave Number ◽  
Critical Wave Number ◽  
Onset Of Convection ◽  
Temperature Boundary ◽  
The Stability ◽  
Rayleigh Benard

The effect of Suction – injection combination on the onset of Rayleigh – Bénard electroconvection micropolar fluid is investigated by making a linear stability analysis. The Rayleigh-Ritz technique is used to obtain the eigenvalues for different velocity and temperature boundary combinations. The influence of various parameters on the onset of convection has been analysed. It is found that the effect of Prandtl number on the stability of the system is dependent on the SIC being pro-gravity or anti-gravity. A similar Pe-sensitivity is found in respect of the critical wave number. It is observed that the fluid layer with suspended particles heated from below is more stable compared to the classical fluid layer without suspended particles.

scholarly journals Thermal instability of Walters B' viscoelastic fluid permeated with suspended particles in hydromagnetics in porous medium

2004 ◽  
Vol 8 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Pardeep Kumar ◽  
Jit Singh ◽  
Roshan Lal
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Newtonian Fluid ◽  
Viscoelastic Fluid ◽  
Thermal Instability ◽  
Suspended Particles ◽  
Stationary Convection ◽  
Onset Of Convection ◽  
Medium Permeability ◽  
The Magnetic Field

The effect of suspended particles on the thermal instability of Walters B' viscoelastic fluid in hydromantic in porous medium is considered. For stationary convection, Walters B' viscoelastic fluid behaves like a Newtonian fluid. The medium permeability and suspended particles has ten the onset of convection whereas the magnetic field postpones the onset of convection, for the case of stationary convection. The magnetic field and viscoelasticity intro duce oscillatory modes in the system which was non-existent in their absence.

scholarly journals Electro-Hydrodynamic Convection in a Rotating Dielectric Micropolar Fluid Layer

2019 ◽  
Vol 24 (4) ◽  
pp. 106-124
Author(s):  
H. Kaur ◽  
G.N Verma
Keyword(s):  
Dispersion Relation ◽  
Electric Field ◽  
Prandtl Number ◽  
Micropolar Fluid ◽  
Fluid Layer ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Stability Criteria ◽  
Onset Of Convection ◽  
Stabilizing Effect

Abstract Thermal convection of a rotating dielectric micropolar fluid layer under the action of an electric field and temperature gradient has been investigated. The dispersion relation has been derived using normal mode analysis. The effects of the electric Rayleigh number, micropolar viscosity, Taylor number and Prandtl number on stability and over stability criteria are discussed. It is found that rotation postpones the instability in the fluid layer, while the Prandtl number and rotation both have a stabilizing effect. It is also observed that the micropolar fluid additives have a stabilizing effect, whereas the electric field has a destabilizing effect on the onset of convection stability.

Effect Of Dust Particles On Thermal Convection In A Ferromagnetic Fluid

2005 ◽  
Vol 60 (7) ◽  
pp. 494-502 ◽  
Author(s):  
◽  
Anupama Sharma ◽  
Divya Sharma ◽  
R. C. Sharma
Keyword(s):  
Rayleigh Number ◽  
Thermal Convection ◽  
Uniform Magnetic Field ◽  
Fluid Layer ◽  
Dust Particles ◽  
Free Boundaries ◽  
Stationary Convection ◽  
Ferromagnetic Fluid ◽  
Critical Wavenumber ◽  
Thermal Rayleigh Number

This paper deals with the theoretical investigation of the effect of dust particles on the thermal convection in a ferromagnetic fluid subjected to a transverse uniform magnetic field. For a flat ferromagnetic fluid layer contained between two free boundaries, the exact solution is obtained, using a linear stability analysis. For the case of stationary convection, dust particles and non-buoyancy magnetization have always a destabilizing effect. The critical wavenumber and critical magnetic thermal Rayleigh number for the onset of instability are also determined numerically for sufficiently large values of the buoyancy magnetization parameter M1. The results are depicted graphically. It is observed that the critical magnetic thermal Rayleigh number is reduced because the heat capacity of the clean fluid is supplemented by that of the dust particles. The principle of exchange of stabilities is found to hold true for the ferromagnetic fluid heated from below in the absence of dust particles. The oscillatory modes are introduced by the dust particles. A sufficient condition for the non-existence of overstability is also obtained.

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