Presence Of Temperature-dependent Viscosity Research Articles

Bioconvective radiative unsteady Casson nanofluid flow across two concentric stretching cylinders with variable viscosity and variable thermal conductivity

The role of variable viscosity and variable thermal conductivity in nanofluid flows is significant, as they can strongly influence the flow behavior and heat transfer performance of nanofluids. Keeping in mind the importance of these effects of variable characteristics, our motivation in this study is to investigate the role of nonlinear radiative heat flux on unsteady Casson nanofluid flow across two concentric stretched cylinders in the presence of temperature-dependent viscosity and thermal conductivity. A convective condition on the inner cylinder wall is also considered. In addition, the nanofluid is immersed with microorganisms that can swim and move independently. The addition of microorganisms has a significant role in the stability of the nanofluid flow. The influence of thermophoresis and Brownian motion on the flow, heat, mass, and microorganisms are scrutinized by employing the Buongiorno model. The governing flow equations are converted into a system of differential equations engaging similarity transformations, and the bvp4c method is employed to solve it numerically. Engineering parameters are computed and tabulated numerically. The findings demonstrate that as the unsteadiness parameter upsurges, the radial profile intensifies while the axial profile diminishes near the outer cylinder surface. It is also comprehended that both Lewis and bioconvective Lewis numbers reduce the motile density profiles. The accuracy of the presented model is also given in a graphical illustration by comparing it with a published result in a limiting case.

Computational Analysis of Soret and Dufour Effects on Nanofluid Flow Through a Stenosed Artery in the Presence of Temperature-Dependent Viscosity

Abstract In this study, the Soret and Dufour effects in a composite stenosed artery were combined with an analysis of the effect of varying viscosity on copper nanofluids in a porous medium. Blood viscosity, which changes with temperature, is taken into account using the Reynolds viscosity model. The finite difference approach is used to quantitatively solve the governing equations. For use in medical applications, the effects of the physical parameters on velocity, temperature and concentration along the radial axis have been investigated and physically interpreted. The results are graphically displayed and physically defined in order to facilitate comprehension of the various phenomena that occur in the artery when nanofluid is present. It is observed that the Soret effect increases the rate of heat transfer but decreases the rate of mass transfer. The new study enhances knowledge of non-surgical treatment options for stenosis and other abnormalities, hence reducing post-operative complications. Additionally, current research may have biomedical applications such as magnetic resonance angiography (MRA), which provide a picture of an artery and enable identification of any anomalies, and thus may be useful

Slanting transport of hybrid (MWCNTs-SWCNTs/H2O) nanofluid upon a Riga plate with temperature dependent viscosity and thermal jump condition

The present exploration communicates the oblique transport of hybrid nanofluid containing MWCNTs (Multi Walled Carbon Nanotubes) and SWCNTs (Single Walled Carbon Nanotubes) over a moving/ stationary Riga plate in presence of temperature dependent viscosity and thermal jump condition at the surface. Comparison of heat transfer characteristics of traditional nanofluid emerging hybrid nanofluid, containing carbon nanotubes upon a stationary or moving surface is made. Modified Brinkman's viscosity model is used to study viscosity variation in flow regime. Oblique flow of Hybrid CNTs based fluid with variable viscosity and thermal jump condition has never been investigated in the past. The governing flow problem is converted into ODEs using similarity variables which are subsequently solved numerically using Runge-Kutta Fehlberg integration through computational software Maple. The investigation deals with some key parameters such as viscosity variation parameter, thermal slip parameter, modified magnetic parameter, width parameter and stretching ratio parameter through graphical representations of velocity, temperature and concentration of fluid. It is perceived that rate of heat transfer declines with viscosity variation parameter but it is higher in magnitude for the case of moving Riga plate as compared with stationary Riga plate. Normal skin friction declines while tangential skin friction rises with variable viscosity parameter.

Could the Réunion plume have thinned the Indian craton?

AbstractThick and highly viscous roots are the key to cratonic survival. Nevertheless, cratonic roots can be destroyed under certain geological scenarios. Eruption of mantle plumes underneath cratons can reduce root viscosity and thus make them more prone to deformation by mantle convection. It has been proposed that the Indian craton could have been thinned due to eruption of the Réunion plume underneath it at ca. 65 Ma. In this study, we constructed spherical time-dependent forward mantle convection models to investigate whether the Réunion plume eruption could have reduced the Indian craton thickness. Along with testing the effect of different strengths of craton and its surrounding asthenosphere, we examined the effect of temperature-dependent viscosity on craton deformation. Our results show that the plume-induced thermomechanical erosion could have reduced the Indian craton thickness by as much as ~130 km in the presence of temperature-dependent viscosity. We also find that the plume material could have lubricated the lithosphere-asthenosphere boundary region beneath the Indian plate. This could be a potential reason for acceleration of the Indian plate since 65 Ma.

Numerical simulation for magnetized transport of hybrid nanofluids with exponential space-based heat source

The prime aim of this investigation is to discuss the two-dimensional steady analysis of hybrid nanoliquids in the existence of magnetohydrodynamics (MHD), thermally radiation and viscous dissipation effects over a linear stretchable sheet. Carbon nanotubes (SWCNT and MWCNT) with copper (Cu) are comprised in the propylene glycol-based fluid. The significance of propylene glycol-based fluid is affected under the exponential space-based heat source phenomenon. The remarkable role of propylene glycol on thermal transport of hybrid nanoliquids is influenced in the presence of temperature-dependent viscosity. The highly nonlinear governing partial differential structures are reduced to nonlinear ODEs by using suitable transformations. The transformed nonlinear ODEs of flow problem have been solved numerically by employing bvp4c (shooting) scheme with Lobatto-IIIA formula in MATLAB. The physical outcomes of involved parameters are obtained by utilizing the graphical and tabular data. The heat transport rate and the skin friction under the numerical data are also presented. From the results, we concluded that the velocity of fluid is declined for higher nanoparticles volume fraction. Velocity of fluid is declined with growing magnetic parameter. Furthermore, the temperature is upgraded with the growing thermal Biot number.

Steady Fully Developed Mixed Convection Flow in a Vertical Channel with Heat and Mass Transfer and Temperature-Dependent Viscosity: An Exact Solution

Abstract An exact solution for mixed convection flow with temperature-dependent viscosity in a vertical channel subject to wall asymmetric heating and concentration is obtained. The momentum, concentration, and energy equations governing the flow configuration are derived and solved exactly by incorporating the variable viscosity term, which is assumed to exponentially decrease/increase with temperature difference into the momentum equation. The roles of governing parameters are depicted with the aid of tables and line graphs. Results show that buoyancy ratio parameter can bring about the occurrence of flow reversal at the walls. It is also found that heat transfer, total species rate, skin friction, and reverse flow occurrence are enhanced in the presence of temperature-dependent viscosity.

Remarkable role of [formula omitted] on transportation of [formula omitted] hybrid nanoparticles influenced by thermal deposition and internal heat generation

The present work focuses on examining nanofluidic transport in presence of temperature dependent viscosity. In order to conduct a comparative investigation Silicon dioxide and Molybdenum disulfide nanoparticles are considered to be suspended in propylene glycol. Furthermore, heat transfer has been inspected for nano and hybrid nanofluids influenced by internal heat source/sink, thermal radiation, and heat dissipation. Additionally, the Cartesian coordinate system opts for mathematical formulation of governing equations. Moreover, similarity analysis is employed to obtain the system of highly nonlinear coupled equations which is solved numerically by means of shooting technique. The key findings include that nanofluid and hybrid nanofluid floe decelerates for increasing values of the viscosity parameter and magnetic parameter while a contrary trend was observed for the rising values of Grashof number. Volumetric fraction ϕ1 and ϕ2 contributed in decelerating fluid flow for plate-shaped particles of nanofluid as well as of hybrid nanofluid. Temperature distribution up surged for rising values of Biot number, Eckert number, viscosity parameter, magnetic parameter, heat generation parameter and lessened for rising values of radiation parameter, Grashof number. This trend was noted for SiO2 and MoS2−SiO2 nanofluids. Moreover, magnetic field, viscous dissipation and heat generation contributed in rising Nusselt number while opposite behavior was observed in presence of thermal radiation and convective boundaries. Furthermore, the maximum Nusselt number was attained for needle shape nanoparticles of MoS2−SiO2 and the minimum value was noted for plate-shaped SiO2 nanoparticles. Nanoparticle volumetric fractions play role in rising skin fraction of SiO2 nanofluid while it decreased in case of hybrid nanofluid. Moreover, minimum skin fraction was noted for needle-shaped nanoparticles of hybrid nanofluid and the maximum value was recorded for plate-shaped nanoparticles of SiO2 .

Impact of viscosity variation on oblique flow of Cu–H2O nanofluid

The dynamic properties of nanofluids have made them an area of intense research during the past few decades. In this article, flow of nonaligned stagnation point nanofluid is investigated. Copper–water based nanofluid in the presence of temperature-dependent viscosity is taken into account. The governing nonlinear coupled ordinary differential equations transformed by partial differential equations are solved numerically by using fourth-order Runge–Kutta–Fehlberg integration technique. Effects of variable viscosity parameter on velocity and temperature profiles of pure fluid and copper–water nanofluid are analyzed, discussed, and presented graphically. Streamlines, skin friction coefficients, and local heat flux of nanofluid under the impact of variable viscosity parameter, stretching ratio, and solid volume fraction of nanoparticles are also displayed and discussed. It is observed that an increase in solid volume fraction of nanoparticles enhances the magnitude of normal skin friction coefficient, tangential skin friction coefficient, and local heat flux. Viscosity parameter is found to have decreasing effect on normal and tangential skin friction coefficients whereas it has a positive influence on local heat flux.

Unsteady magneto-nanofluid flow caused by a rotating cone with temperature dependent viscosity: A surgical implant application

Nanofluids are potential heat transfer fluids with enhanced thermal and physical properties. In particular, the fluids embedded with titanium nanoparticles have tendency to control the heat transfer mechanism in surgical implant applications such as glass covering of iris, retina and glaucoma etc. External magnetic fields are capable to set the thermal and physical properties of magnetic-nanofluids and regulate the flow and heat transfer characteristics. With this incentive, a theoretical investigation is performed for exploring the flow and heat transfer behavior of magneto-nanofluids caused by a rotating cone in the presence of temperature dependent viscosity and heat source/sink. For this study, we considered Ti and Ti-alloy (Ti6Al4V is a titanium alloy with 90% titanium, 6% aluminum and 4% Vanadium) nanoparticles embedded in water. With the aid of similarity variables, we transformed the governing equations as ordinary differential equations and numerical solutions are found by employing Runge-Kutta and Newton's methods. We discussed the friction factor coefficients, local Nusselt number, flow and heat transfer performance of both nanofluids with the assistance of graphs and tables. We found that the heat transfer performance of Ti-water nanofluid is high when compared with the heat transfer performance of Ti-alloy water nanofluid. From this we can conclude that Ti-alloy combination nanofluids are useful for cooling processes.

Retraction of “Influence of thermophoresis particle deposition and chemical reaction on unsteady non-Darcy MHD mixed convective flow over a porous wedge in the presence of temperature-dependent viscosity”

An analysis is presented to investigate the effect of thermophoresis particle deposition and temperature dependent viscosity on unsteady non-Darcy mixed convective heat and mass transfer of a viscous and incompressible fluid past a porous wedge in the presence of chemical reaction. The wall of the wedge is embedded in a uniform non-Darcian porous medium in order to allow for possible fluid wall suction or injection. The governing partial differential equations of the problem, subjected to their boundary conditions, are solved numerically by applying an efficient solution scheme for local nonsimilarity boundary layer analysis. Numerical calculations are carried out for different values of dimensionless parameters arising in the problem. The results are compared with available ones in the literature and excellent agreement is obtained. An analysis of the obtained results shows that the flow field is influenced appreciably by the chemical reaction and thermophoresis particle deposition.

RETRACTED ARTICLE: Influence of thermophoresis particle deposition and chemical reaction on unsteady non-Darcy MHD mixed convective flow over a porous wedge in the presence of temperature-dependent viscosity

An analysis is presented to investigate the effect of thermophoresis particle deposition and temperature dependent viscosity on unsteady non-Darcy MHD mixed convective heat and mass transfer of a viscous, incompressible and electrically conducting fluid past a porous wedge in the presence of chemical reaction. The wall of the wedge is embedded in a uniform non-Darcian porous medium in order to allow for possible fluid wall suction or injection. The results are compared with those known from the literature and excellent agreement between the results is obtained. The governing partial differential equations of the problem, subjected to their boundary conditions, are solved numerically by applying an efficient solution scheme for local nonsimilarity boundary layer analysis. Numerical calculations are carried out for different values of dimensionless parameter in the problem and an analysis of the results obtained show that the flow field is influenced appreciably by the applied magnetic field and thermophoresis particle deposition.

Effect of thermophoresis particle deposition and chemical reaction on unsteady MHD mixed convective flow over a porous wedge in the presence of temperature-dependent viscosity

An analysis is presented to investigate the effect of thermophoresis particle deposition and temperature dependent viscosity on unsteady MHD mixed convective heat and mass transfer of a viscous, incompressible and electrically conducting fluid past a porous wedge in the presence of chemical reaction. The wall of the wedge is embedded in a uniform non-Darcian porous medium in order to allow for possible fluid wall suction or injection. The results are compared with those known from the literature and excellent agreement between the results is obtained. The governing partial differential equations of the problem, subjected to their boundary conditions, are solved numerically by applying an efficient solution scheme for local nonsimilarity boundary layer analysis. Numerical calculations are carried out for different values of dimensionless parameter in the problem and an analysis of the results obtained show that the flow field is influenced appreciably by the applied magnetic field and thermophoresis particle deposition.

Impact of thermophoresis particle deposition and chemical reaction on unsteady non-Darcy mixed convective flow over a porous wedge in the presence of temperature-dependent viscosity

An analysis is presented to investigate the effect of thermophoresis particle deposition and temperature dependent viscosity on unsteady non-Darcy mixed convective heat and mass transfer of a viscous and incompressible fluid past a porous wedge in the presence of chemical reaction. The wall of the wedge is embedded in a uniform non-Darcian porous medium in order to allow for possible fluid wall suction or injection. The governing partial differential equations of the problem, subjected to their boundary conditions, are solved numerically by applying an efficient solution scheme for local nonsimilarity boundary layer analysis. Numerical calculations are carried out for different values of dimensionless parameters arising in the problem. The results are compared with available ones in the literature and excellent agreement is obtained. An analysis of the obtained results shows that the flow field is influenced appreciably by the chemical reaction and thermophoresis particle deposition.