Effect Of G-jitter Research Articles

Weakly non-linear stability analysis of g-jitter induced Rayleigh–Bénard convection under inclined surfaces

This study investigated the effect of g-jitter on the Rayleigh–Bénard convection between inclined surfaces whose lower layer is concentrated with a solute C. The problem is formulated using the Ginzburg–Landau (GL) equation, which is time-dependent non-autonomous ordinary differential equation and derived from a weakly non-linear theory and Fredholm solvability condition. The graphical solution of the GL equation is obtained with the help of MATHEMATICA by using the Runge–Kutta fourth-order method. The impact of various flow parameters on the convective rate of heat and mass transport has been discussed. The heat and mass transport is found to be advanced by the non-dimensional parameters viz. modulations’ amplitude (δ), Lewis number (Le), and solute Rayleigh number (RC), but it is suppressed by the angle of inclination ϕ.

Significance of Nanoparticle Radius and Gravity Modulation on Dynamics of Nanofluid over Stretched Surface via Finite Element Simulation: The Case of Water-Based Copper Nanoparticles

This communication studies the importance of varying the radius Dp of Copper nanoparticles for microgravity-modulated mixed convection in micropolar nanofluid flux under an inclined surface subject magnetic field and heat source. In the current era, extremely pervasive modernized technical implementations have drawn attention to free convection governed by g-jitter force connected with microgravity. Therefore, fixed inter-spacing of nanoparticles and effects of g-jitter on the inclined surface are taken into consideration. A mathematical formulation based on conservation principles was non-dimensionalized by enforcement of similarity transformation, yielding a related set of ODEs. The convective non-linearity and coupling, an FE discretization, was implemented and executed on the Matlab platform. The numerical process’ credibility was ensured for its acceptable adoption with the defined outcomes. Then, the computational endeavor was continued to elucidate the impacts of various inputs of Dp, the amplitude of modulation ϵ, material parameter β, mixed convection parameter λ, inclination angle γ, and magnetic parameter M. The enlarging size of nanoparticles accelerated the nanofluid flow due to the depreciation of viscosity and receded the fluid temperature by reducing the surface area for heat transportation. The modulated Nusselt number, couple stress, and skin friction coefficient are significantly affected by the variation of Dp, M, β, λ, and ϵ. These results would benefit experts dealing with upper space transportation and materials’ performance, such as the effectualness of chemical catalytic reactors and crystals.

G-Jitter Effects on Transient Natural Convection Couette Flow in a Vertical Channel

This article investigates the effects of g-jitter on transient natural convection Couette flow in a vertical channel. Fully developed laminar time dependent flow is considered. The flow formation is caused by the buoyancy force arising from the temperature gradient as a result of asymmetric heating of parallel plates as well as constant motion of one of the plates. The method of Laplace transforms is used to obtain the expressions for temperature and velocity which are used to compute the Nusselt number, skin-friction, mass flux and mean temperature in Laplace domain then the Riemann-sum approximation is used to invert our expressions from Laplace domain to time domain. During the course of investigation, it was found that the influence of heat generation/absorption parameter on the rate of heat transfer on one plate is the reverse of the influence on the other plate. As the amplitude of the g-jitter increases, the velocity of the fluid increases and also the influence of frequency of oscillations of g-jitter on mass flux and mean temperature depends on time.

Quadratic Convective Nanofluid Flow at a Three-Dimensional Stagnation Point with the g-Jitter Effect

The nonlinear density variation with temperature happens in many thermal applications like solar collectors, energy production, heat exchangers, and combustions, and it gives a significant impact on heat transfer and fluid flows. Thus, a nonlinear convective of an unsteady stagnation point flow under the influence of gravity modulation in the presence of water-based nanoparticles alumina (Al2O3) is studied here. Suitable variables are utilized to reduce the highly coupled nonlinear governing equations into a system of dimensionless simple partial differential equations. The Keller-box method is then applied to solve the consequent governing equations. Velocity and temperature profiles for various values of pertinent parameters are displayed graphically and discussed. The results indicate that the quadratic convection has enhanced the fluid flow and heat transport. Furthermore, the nonlinear convection parameter and the nanoparticles volume fractions have delivered a positive effect on the skin friction and the rate of heat transfer.

Stagnation Point Flow of a Hybrid Nanofluid Under the Gravity Modulation Effect

The effectiveness of the heat transfer fluid in the cooling or heating process determines the optimal performance of the nuclear reactor, microelectronic devices, and chip production. Since thermal conductivity improved in hybrid nanofluids, the current study sought to investigate the unsteady free convection hybrid nanofluid flow near a stagnation point as influenced by g-jitter. A hybrid nanofluid consisted of copper (Cu) and alumina (Al2O3) nanoparticles, which were added into water to form Cu-Al2O3/water was considered. Next, relevant variables transformed the governing equation into dimensionless equations before being solved numerically using a centered implicit finite difference method. The fluid field and heat transfer were discussed concerning the stagnation point curvature ratio. The results showed that the g-jitter effect caused fluctuation in all profiles and physical quantities. The frequency and amplitude of the g-jitter reduced the velocity profile while improving the temperature distribution. The heat transfer rate increased by 10.77% when the hybrid nanoparticles volume fractions rose from 0.1 to 0.2. However, the presence of hybrid nanoparticles had reduced the thickness of the momentum boundary layer due to an increase in the local skin friction.

G-Jitter Effects on Transient Natural Convection Couette Flow in a Vertical Channel with Convective Boundary Condition

This article investigates the effects of g-jitter on transient natural convection Couette flow in a vertical channel. Fully developed laminar time dependent flow is considered. The flow formation is caused by the buoyancy force arising from the temperature gradient as a result of asymmetric heating of parallel plates as well as constant motion of one of the plates. The method of Laplace transforms is used to obtain the expressions for temperature and velocity which are used to compute the Nusselt number, skin-friction, mass flux and Mean temperature in Laplace domain then the Riemann-sum approximation is used to invert our expressions from Laplace domain to time domain. During the course of investigation, it was found that the influence of heat generation/absorption parameter on the rate of heat transfer on one plate is the reverse of the influence on the other plate. Increase in convective coefficients of the bounding plates constitute an enhancement to heat transfer, skin friction, mass flux as well as mean temperature within the channel

Hybrid nanofluids: Significance of gravity modulation, heat source/ sink, and magnetohydrodynamic on dynamics of micropolar fluid over an inclined surface via finite element simulation

An exploration is sought for improved thermal transportation across an extending inclined sheet in the upper space to be influenced by periodic micro gravity g*(τ)=g0(1+acos(πωt)) and magnetic field B0. The mixed convection induced by g-jitter effects is studied for the flow of two colloidal liquids; the alone micropolar nano fluid (copper/ water) and micropolar hybrid nano fluid (alumenia-copper/ water). The leading formulation in its transformed form as ordinary differential format is manipulated via finite-element discretization. A computational code is coded in Matlab script to assess the impacts of involved parameters on dynamic of fluid. The differentiated enhanced performance of hybrid naofluids is observed in this upper space g-jitter influenced flow. The fluid velocity is slowed against growing strength of Hartmann number, but it becomes faster against micropolar material quantity. Both velocity and temperature distribution for hybrid nanofluid flow attains higher values in comparison with those of alone mono-nanofluid. The fluctuation of skin-friction factor and heat flux gradient improves with larger inputs of amplitude of modulation.

Numerical simulation of single bubble evolution in low gravity with fluctuation

The nucleate boiling under low gravity was solved numerically, with the thermocapillary force considered in the momentum equations. The two-phase interface was captured with the phase field method, and the superheated layer was included in the model. The effects of thermocapillary convection and g-jitter (fluctuating gravity) on the bubble dynamics and heat transfer were explored. It was found that the thermocapillary convection shortened the growth period of the bubble by about 0.26 s in the low gravity (low-g). The affected area of the temperature and flow fields was wider with consideration of thermocapillary convection, and the heat transfer was enhanced consequently. Moreover, the bubble dynamics showed different characteristics in the conditions with and without the g-jitter. The velocity of the contact line fluctuated between positive and negative values in g-jitter. As the amplitude of the g-jitter increased from 0 to 0.04, the departure time and departure radius decreased by 31.2% and 14.1%, respectively. Nevertheless, the average heat flux increased with the increase of the g-jitter amplitude. The frequency of g-jitter showed a negative correlation with departure time and departure radius of the bubble, whereas average heat flux showed a positive correlation with the frequency of g-jitter.

Significance of suction/injection, gravity modulation, thermal radiation, and magnetohydrodynamic on dynamics of micropolar fluid subject to an inclined sheet via finite element approach

This communication explores the significance of suction/injection for gravity modulation mixed convection in micropolar fluid flow due to an inclined sheet in the presence of magnetic field and thermal radiation. In recent years, very extensive modern technological applications have rise the interest in mixed convection controlled by g-jitter forces associated with microgravity. The novelty of the present study is effects of g-jitter on dynamics of micropolar fluid adjustable inclination to the sheet taken into account. Mathematical formulation based on usual laws of conservation is non dimensionalized with emerging parameters through implementation of similarity transform to yield a corresponding set of partial differential equations. In the face of convective non linearity combined with coupling due to mixed convection and micropolarity, a finite element discretization is harnessed to be coded and run on Matlab platform. The credibility of numerical procedure is assured for its acceptable adoption with the established results. The growing strength of amplitude of modulation is showing proportional decrease and increase in the fluctuation of heat transfer and skin friction coefficients, and the fluctuation of reduced skin friction factor, couple stress, and Nusselt number improves with larger inputs of amplitude. These findings would be helpful to experts dealing with upper space heat transportation, performance of materials such as crystals and effectiveness of chemical catalytic reactors.

Effects of g-jitter and radiation on three-dimensional double diffusion stagnation point nanofluid flow

The unsteady double diffusion of the boundary layer with the nanofluid flow near a three-dimensional (3D) stagnation point body is studied under a microgravity environment. The effects of g-jitter and thermal radiation exist under the microgravity environment, where there is a gravitational field with fluctuations. The flow problem is mathematically formulated into a system of equations derived from the physical laws and principles under the no-slip boundary condition. With the semi-similar transformation technique, the dimensional system of equations is reduced into a dimensionless system of equations, where the dependent variables of the problem are lessened. A numerical solution for the flow problem derived from the system of dimensionless partial differential equations is obtained with the Keller box method, which is an implicit finite difference approach. The effects studied are analyzed in terms of the physical quantities of principle interest with the fluid behavior characteristics, the heat transfer properties, and the concentration distributions. The results show that the value of the curvature ratio parameter represents the geometrical shape of the boundary body, where the stagnation point is located. The increased modulation amplitude parameter produces a fluctuating behavior on all physical quantities studied, where the fluctuating range becomes smaller when the oscillation frequency increases. Moreover, the addition of Cu nanoparticles enhances the thermal conductivity of the heat flux, and the thermal radiation could increase the heat transfer properties.

G-jitter effect on mass transport in electrically conducting Newtonian fluid

The present article describes the g-jitter effect on the rate of mass transport (Sherwood number Sh) in the electrically-conducting Newtonian fluid between two infinite horizontal plates at a distance ’d’ apart. It is assumed that concentration at the upper wall is S0+▵S and S0 is at the lower wall. A magnetic force of constant strength H0 is applied perpendicular to the XOY-plane which generates an induced magnetic field. We have used the asymptotic analysis method to solve the system of differential equations. The expression of Sherwood number depends on the amplitude of stream function which can be determined by the real cubic Landau equation. The influence of different dimensionless quantities on the convective mass transport are presented graphically. It is also observed that the Sherwood number could be tuned suitably by adjusting the amplitude and frequency of gravity modulation.

Throughflow and G-Jitter Effects on Oscillatory Convection in a Rotating Porous Medium

The impact of vertical throughflow and g-jitter effect on rotating porous medium is investigated. A feeble nonlinear stability analysis associate to complex Ginzburg-Landau equation (CGLE) has been studied. This weakly nonlinear analysis performed for a periodic mode of convection and quantified heat transport in terms of the Nusselt number, which is governed by the non-autonomous advanced CGLE. Each idea, rotation and throughflow is used as an external mechanism to the system either to extend or decrease the heat transfer. The results of amplitude and frequency of modulation on heat transport are analyzed and portrayed graphically. Throughflow has dual impact on heat transfer either to increase or decrease heat transfer in the system. Particularly the outflow enhances and inflow diminishes the heat transfer. High centrifugal rates promote heat transfer and low centrifugal rates diminish heat transfer. The streamlines and isotherms area portrayed graphically, the results of rotation and throughflow on isotherms shows convective development.

G-Jitter effect on heat and mass transfer of 3D stagnation point nanofluid flow with heat generation

Abstract The dynamics of viscous copper nanofluid double diffusion problem driven at three-dimensional stagnation point flow induced by heat generation under microgravity environment was analyzed numerically. The nature of the flow was interpreted into a system of differential equation. By imposing Keller box approach, profiles and physical quantities of principle interest result were analyzed. Profiles results showed a natural convection pattern and satisfied the boundary condition. Besides that, curvature ratio gives a significant effect on skin friction. Larger size of frequency of oscillation reduce the peak values of all physical quantities. The analysis on Nusselt shows an enhancement with the additional of nanoparticles into the conventional fluid. Meanwhile, additional resistance at the boundaries was produced due to the presence of copper nanoparticles. A heat source was produced from the heat generation effect inside the fluid reduced the rate of heat transfer at the body due to the additional temperature at the fluid.

G-jitter fully developed heat transfer by mixed convection flow in a vertical channel with constant heat flux

A theoretical study of mixed convection heat transfer was carried out in an infinite length of vertical channel with both open ends. One of the vertical plates was prescribed with constant heat flux. The effect of g-jitter was also taken into consideration. The Fourier method was utilized to solve the resulting governing equations. The behavior of the fluid temperature and velocity of the flow were studied and presented graphically in this paper. The graphical results were later on analyzed and discussed. The behavior of steady state flow was also investigated. Results confirmed that as wall temperature increased, the fluid temperature increased. The velocity increased due to increments in mixed convection and oscillation parameter, on the other hand, it decreased as a frequency of g-jitter increased.

G-Jitter Free Convection Flow of Nanofluid in The Three-Dimensional Stagnation Point Region

The three dimensional free convection boundary layer flow near a stagnation point region is embedded in viscous nanofluid with the effect of g-jitter is studied in this paper. Copper (Cu) and aluminium oxide (Al2O3) types of water base nanofluid are cho- sen with the constant Prandtl number, Pr=6.2. Based on Tiwari-Das nanofluid model, the boundary layer equation used is converted into a non-dimensional form by adopting non- dimensional variables and is solved numerically by engaging an implicit finite-difference scheme known as Keller-box method. Behaviors of fluid flow such as skin friction and Nusset number are studied by the controlled parameters including oscillation frequency, amplitude of gravity modulation and nanoparticles volume fraction. The reduced skin friction and Nusset number are presented graphically and discussed for different values of principal curvatures ratio at the nodal point. The numerical results shows that, in- crement occurs in the values of Nusset number with the presence of solid nanoparticles together with the values of the skin friction. It is worth mentioning that for the plane stagnation point there is an absence of reduced skin friction along the y-direction where as for axisymmetric stagnation point, the reduced skin friction for both directions are the same. As nanoparticles volume fraction increased, the skin friction increased as well as the Nusset number. The results, indicated that skin frictions of copper are found higher than aluminium oxide.

G-JITTER INDUCED MIXED CONVECTION FLOW BETWEEN TWO PARALLEL PLATES WITH NEWTONIAN HEATING

This article deals with the mixed convection flow between two vertical parallel plates with the effect of g-jitter. Newtonian heating is considered on the left wall of the plate. The governing equations of heat and mass transfer are modelled in the Cartesian coordinate system with the effect of g-jitter. Non-dimensional variables are used to transform the governing equations together with the boundary layer condition. Separation of variables method are applied to provide the exact analytical solutions for the velocity, temperature and concentration profiles. The obtained solutions are computed to produce the graphical results. It is showed that due to an increasing value of wall temperature and thermal conjugate parameter, the fluid temperature increased. As wall concentration increases, the fluid concentration also increased. Meanwhile, the velocity increasing as mixed convection and thermal conjugate parameter increased. Contradict, the velocity decreasing as the value of buoyancy ratio and frequency increased.

THE FLOW AND HEAT TRANSFER WITH THERMAL RADIATION AT A GENERAL STAGNATION POINT IN NANOFLUID UNDER MICROGRAVITY ENVIRONMENT

The fundamental research near a boundary layer nanofluid flow at a stagnation point region with thermal radiation effect is conducted under microgravity environment. The mathematical formulation is modified from physical law to represent the physical characteristic of the flow and the system of the equation are solved numerically using Keller box method. The flow is analyzed in terms of physical quantities of principal interest such as skin friction and Nusset number. Parameters consider in this flow such as curvature ratio, amplitude of modulation, frequency of oscillation, nanoparticles volume friction and thermal radiation is analyzed numerically and presented graphically. From the analysis, g-jitter effect will produce a fluctuating result to the skin frictions and Nusset number indicate the singularity solution in the flow. The existing of nanoparticles and thermal radiation is found to increase the rate of heat transfer of the flow.

Feedback Control of Chaos in Porous Medium under G-jitter Effects

In the present paper, we studied feedback control of chaotic convection in porous medium under gravity modulation. A non-autonomous system having three differential equations is obtained by employing the truncated Galerkin expansion method in to the modulated momentum and energy equations, called as Lorenz system in the literature. The parameter R demonstrates either periodic or chaotic behavior of the system as increasing R. It is also found that the influence of amplitude of modulation is to advance the chaotic nature in the system whereas the feedback control and frequency of modulation parameters have tendency to delay the chaotic behavior.

Feedback Control of Chaos in Porous Medium under G-jitter Effects

In the present paper, we studied feedback control of chaotic convection in porous medium under gravity modulation. A non-autonomous system having three differential equations is obtained by employing the truncated Galerkin expansion method in to the modulated momentum and energy equations, called as Lorenz system in the literature. The parameter R demonstrates either periodic or chaotic behavior of the system as increasing R. It is also found that the influence of amplitude of modulation is to advance the chaotic nature in the system whereas the feedback control and frequency of modulation parameters have tendency to delay the chaotic behavior.

G-jitter induced mixed convection flow of a second grade fluid past an inclined stretching sheet

An analysis was carried out to study the mixed convection flow of a non-Newtonian second grade fluid past an inclined stretching sheet in the presence of a g-jitter effect. The transformed governing equation, consisting of coupled non-linear partial differential equations, was solved numerically using an implicit finite-difference scheme known as the Keller-box method. The flow and heat transfer characteristics in terms of velocity and temperature profiles as well as the skin friction and heat transfer coefficients influenced by the amplitude of modulation, frequency of oscillation, inclination angle and second grade parameters were presented graphically and analysed in detail. The findings revealed that the heat transfer coefficient is enhanced with an increase in the second grade parameter, whereas the opposite trend is observed for the skin friction coefficient.