The Effect of Gravity Modulation on Double Diffusive Convection in the Presence of Applied Magnetic Field and Internal Heat Source

2020 ◽  
Vol 12 (6) ◽  
pp. 792-805
Author(s):  
Palle Kiran ◽  
S. H. Manjula ◽  
R. Roslan
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Finite Amplitude ◽  
Gravity Modulation ◽  
Nonlinear Stability Analysis ◽  
Ginzburg Landau ◽  
Weakly Nonlinear ◽  
Double Diffusive

We have investigated the study of double diffusive stationary convection in the presence of applied magnetic field and internal heating. A weakly nonlinear stability analysis has been performed using the finite amplitude Ginzburg-Landau model. This finite amplitude of convection is obtained at third order of the system. It is assumed that the buoyancy term has two parts, steady and oscillatory parts. The second part is varying sinusoidally with time and vibrates the system with finite amplitude δ1 and frequency ω. The effects of δ1 and on heat/mass transports have been analysed and depicted graphically. The studies are established that the heat/mass transports can be controlled effectively by gravity modulation. Further, it is found that internal Rayleigh number Ri is to enhance heat transfer and reduces the mass transfer in the system.

scholarly journals The Effect of Thermal Modulation on Double Diffusive Convection in the Presence of Applied Magnetic Field and Internal Heat Source

2021 ◽  
Vol 26 (1) ◽  
pp. 135-155
Author(s):  
S.H. Manjula ◽  
P. Suresh ◽  
M.G. Rao
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Phase Modulation ◽  
Lower Boundary ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Finite Amplitude ◽  
Nonlinear Stability Analysis ◽  
Thermal Modulation ◽  
Double Diffusive

AbstractThe investigation of thermal modulation on double-diffusive stationary convection in the presence of an applied magnetic field and internal heating is carried out. A weakly nonlinear stability analysis has been performed using the finite-amplitude Ginzburg-Landau model. This finite amplitude of convection is obtained at the third order of the system. The study considers three different forms of temperature modulations. OPM-out of phase modulation, LBMO-lower boundary modulation, IPM-in phase modulation. The finite-amplitude is a function of amplitude δT, frequency ω and the phase difference θ. The effects of δT and ω on heat/mass transports have been analyzed and depicted graphically. The study shows that heat/mass transports can be controlled effectively by thermal modulation. Further, it is found that the internal Rayleigh number Ri enhances heat transfer and reduces the mass transfer in the system.

scholarly journals Study of Weakly nonlinear Mass transport in Newtonian Fluid with Applied Magnetic Field under Concentration/Gravity modulation

2019 ◽  
Vol 8 (1) ◽  
pp. 513-522 ◽  
Author(s):  
Om Prakash Keshri ◽  
Vinod K. Gupta ◽  
Anand Kumar
Keyword(s):  
Mass Transport ◽  
Fluid Layer ◽  
Landau Equation ◽  
Periodic Part ◽  
Gravity Modulation ◽  
Nonlinear Stability Analysis ◽  
Ginzburg Landau ◽  
Weakly Nonlinear ◽  
Mass Transfer Effect ◽  
Time Periodic

Abstract In the present paper, a weakly nonlinear stability analysis is used to analyze the effect of time-periodic concentration/gravity modulation on mass transport. We have considered an infinite horizontal fluid layer with constant appliedmagnetic flux salted from above, subjected to an imposed time-periodic boundary concentration (ITBC) or gravity modulation (ITGM). In the case of ITBC, the concentration gradient between the plates of the fluid layer consists of a steady part and a time-dependent oscillatory part. The concentration of both walls is modulated. In the case of ITGM, the gravity fleld consists of two parts: a constant part and an externally imposed time periodic part, which can be realized by oscillating the fluid layer. We have expanded the infinitesimal disturbances in terms of power series of an amplitude of modulation, which is assumed to be small. Ginzburg-Landau equation is derived for dinding the rate of mass transfer. Effect of various parameters on the mass transport is also discussed. It is found that the mass transport can be controlled by suitably adjusting the frequency and amplitude of modulation.

scholarly journals The Effect of Modulation on Heat Transport by a Weakly Nonlinear Thermal Instability in the Presence of Applied Magnetic Field and Internal Heating

2020 ◽  
Vol 25 (4) ◽  
pp. 96-115
Author(s):  
S.H. Manjula ◽  
Palle Kiran ◽  
G. Narsimlu ◽  
R. Roslan
Keyword(s):  
Magnetic Field ◽  
Heat Transport ◽  
Applied Magnetic Field ◽  
Landau Equation ◽  
Thermal Modulation ◽  
Ginzburg Landau ◽  
Weakly Nonlinear ◽  
The Real ◽  
Ginzburg Landau Equation ◽  
Gravity And Magnetic

AbstractThe present paper deals with a weakly nonlinear stability problem under an imposed time-periodic thermal modulation. The temperature has two parts: a constant part and an externally imposed time-dependent part. We focus on stationary convection using the slow time scale and quantify convective amplitude through the real Ginzburg-Landau equation (GLE). We have used the classical fourth order Runge-Kutta method to solve the real Ginzburg-Landau equation. The effect of various parameters on heat transport is discussed through GLE. It is found that heat transport analysis is controlled by suitably adjusting the frequency and amplitude of modulation. The applied magnetic field (effect of Ha) is to diminish the heat transfer in the system. Three different types of modulations thermal, gravity, and magnetic field have been compared. It is concluded that thermal modulation is more effective than gravity and magnetic modulation. The magnetic modulation stabilizes more and gravity modulation stabilizes partially than thermal modulation.

Throughflow and Gravity Modulation Effects on Double Diffusive Oscillatory Convection in a Viscoelastic Fluid Saturated Porous Medium

2020 ◽  
Vol 12 (5) ◽  
pp. 612-621
Author(s):  
S. H. Manjula ◽  
Palle Kiran
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Saturated Porous Medium ◽  
Finite Amplitude ◽  
Nonlinear Stability Analysis ◽  
Amplitude Analysis ◽  
Ginzburg Landau ◽  
Weakly Nonlinear ◽  
Viscoelastic Parameters ◽  
Retardation Parameter

Weakly nonlinear stability analysis has been performed using the finite amplitude Ginzburg-Landau model. The layer is oscillating vertically in sinusoidal manner. Using the finite amplitude analysis heat mass/transfer is quantified in the system. The disturbances of the flow are expanded in power series of small parameter. In addition to the modulation, the effect of throughflow is discussed on heat/mass transfer in the system. The values of viscoelastic parameters are considered in this paper are λ1 > λ2 and Γ < 1 to validate the problem. The time relaxation parameter λ1 has destabilizing effect, while the time retardation parameter λ2 has stabilizing effect on the system. The effects of amplitude and frequency of modulation on heat/mass transports have been analyzed and depicted graphically. The studies establish that the heat/mass transports can be controlled effectively by g-jitter and throughflow. Further, it is found that better results may obtain for an oscillatory mode of convection.

The effect of magnetic field on Marangoni convection in a nanofluid layer with internal heat source

2017 ◽  
Author(s):  
Izzati Khalidah Khalid ◽  
Nor Fadzillah Mohd Mokhtar ◽  
Zailan Siri ◽  
Zarina Bibi Ibrahim ◽  
Siti Salwa Abd Gani
Keyword(s):  
Magnetic Field ◽  
Heat Source ◽  
Marangoni Convection ◽  
Internal Heat ◽  
Internal Heat Source
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