Centrifugally Driven Convection in a Nanofluid Saturated Rotating Porous Medium with Modulation

International Journal of Applied Mechanics and Engineering

Reddy

et al. 2020

A weakly nonlinear thermal instability is investigated under rotation speed modulation. Using the perturbation analysis, a nonlinear physical model is simplified to determine the convective amplitude for oscillatory mode. A non-autonomous complex Ginzburg-Landau equation for the finite amplitude of convection is derived based on a small perturbed parameter. The effect of rotation is found either to stabilize or destabilize the system. The Nusselt number is obtained numerically to present the results of heat transfer. It is found that modulation has a significant effect on heat transport for lower values of ωf while no effect for higher values. It is also found that modulation can be used alternately to control the heat transfer in the system. Further, oscillatory mode enhances heat transfer rather than stationary mode.

Section: Introductionmentioning

confidence: 99%

The Complex Ginzburg Landau Model for an Oscillatory Convection in a Rotating Fluid Layer

Manjula¹,

International Journal of Applied Mechanics and Engineering

Reddy

et al. 2020

“…It was concluded that oscillatory modes enhance heat transfer more than stationary modes. A number of studies have been devoted to gravity modulation on different models, e.g., on chaotic convection [24,25], on throughflow [26], on rotating nanofluid convection [27], rotating oscillatory convection [28], on throughflow and double diffusive oscillatory convection [29]. The effect of gravity modulation was extensively investigated on different fluid or porous convection.…”

Section: Introductionmentioning

confidence: 99%

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

Manjula

International Journal of Applied Mechanics and Engineering

Narsimlu

et al. 2020

Self Cite

The 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.

“…As a result, Rn plays a dual role in transport media and can be used to regulate the transport of mass and heat. Most of the results related to Rn are followed by Agarwal et al [17,18,20] and Kiran et al [41][42][43][44]. Figures 4c and 5c show the OPM case results of a similar kind.…”

Section: Resultsmentioning

confidence: 68%

“…The effect of g-jitter on nonlinear thermal convection in a porous medium saturated with viscoelastic nanofluid was discussed by Kiran [41]. Kiran et al [42,43] revealed the results of the interactions between internal heating and centrifugal force on nano-convection under thermal modulation. Kiran et al [44] studied porous nanoconvection using a regulated heat source and sink analysis.…”

Section: Introductionmentioning

confidence: 99%

Time-Periodic Thermal Boundary Effects on Porous Media Saturated with Nanofluids: CGLE Model for Oscillatory Mode

Advances in Materials Science

Manjula

2022

Self Cite

The stability of nonlinear nanofluid convection is examined using the complex matrix differential operator theory. With the help of finite amplitude analysis, nonlinear convection in a porous medium is investigated that has been saturated with nanofluid and subjected to thermal modulation. The complex Ginzburg-Landau equation (CGLE) is used to determine the finite amplitude convection in order to evaluate heat and mass transfer. The small amplitude of convection is considered to determine heat and mass transfer through the porous medium. Thermal modulation of the system is predicted to change sinusoidally over time, as shown at the boundary. Three distinct modulations IPM, OPM, and LBMOhave been investigated and found that OPM and LBMO cases are used to regulate heat and mass transfer. Further, it is found that modulation frequency (ω f varying from 2 to 70) reduces heat and mass transfer while modulation amplitude (δ 1 varying from 0.1 to 0.5 ) enhances both.