A numerical analysis of the incompressible two-dimensional flow of a non-Newtonian Williamson fluid is offered by expanding the sheet embedded in a porous medium and combining it with the ...Cattaneo-Christov model. Additionally, it is considered that the thermal conductivity and fluid viscosity both change as a linear function of temperature and an exponential function, respectively. The velocity, temperature and concentration field are all affected by thermal radiation, viscous dissipation, fluid variable properties, chemical reactions, and the slip velocity phenomenon. When the appropriate variables are employed, a system of non-linear, non-dimensional parameters emerges. The shooting method is used to numerically address this system. To better comprehend the impact of dimensionless parameters on dimensionless velocity, concentration, and temperature profiles, physical descriptions are prepared and justified using graphical representations. The values of the local skin-friction coefficient, the rate of heat transfer, and the rate of mass transfer are also investigated using tables. The behavior of changing fluid properties, on the other hand, establishes the link between Williamson fluid flow and the rate of heat mass transfer. According to the results, increasing the slip velocity and viscosity factors lowers both the Nusselt number and the Sherwood number. Also, due to an increase in Deborah number and the chemical reaction parameter, the temperature profiles decrease.
A theoretical model is developed to stimulate electrokinetic transfer through peristaltic movement in a microchannel. The effect of variable viscosity, variable thermal conductivity, and wall ...properties is carried out. Such flows emerge in bio-mimetic pumping systems at the extremely tiny scale of significance in physiological operation, e.g., eye medication shipment systems. The sinusoidal wave-like motion propagates along the channel wall leading to the peristaltic motion. The long-wavelength and petite Reynolds number estimations are supposed to abbreviate the governing formulas. Debye–Hückel linearization is also analyzed. The variable thermal conductivity and variable viscosity parameters are used as perturbation parameters. The graphical outcomes are presented for temperature, velocity, concentration, and streamlines. Biomedical engineers can use the obtained results to create bio-microfluidic mechanisms that may assist in carrying physical liquids.
The current work emphasizes the modelling of the electroosmosis-modulated peristaltic flow of Jeffery liquid. Such flows emerge in understanding the movement of biological fluids in a microchannel, ...such as in targeted drug delivery and blood flow through micro arteries. The non-Newtonian fluid flows inside a non-uniform cross-section and an inclined microchannel. The effects of wall properties and variable fluid properties are considered. The long wavelength and small Re number approximations are assumed to simplify the governing equations. Debye-Hückel linearization is also utilized. The nonlinear governing equations are solved by utilizing the perturbation technique. MATLAB is used for the solution, velocity, temperature, skin friction, coefficient heat transport, concentration, shear wood number, and streamlines expressions. The obtained result in optimal electroosmotic velocity (or Helmholtz-Smoluchowski velocity) increases from −1 to 6; the axial circulation has substantial momentum. For larger optimal electroosmotic velocity, a subsequent boost in an axial electric field causes a significant deceleration. Further, the study helps biomedical engineers to create biomicrofluidics devices that may aid in carrying biological fluids.
The present work focuses on the attributes of flow, heat, and mass transfer together with double diffusive Cattaneo–Christov mechanism with regards to their applications. The aim of this study is to ...investigate the non-Newtonian Powell–Eyring fluid flow, taking into account the twofold impact of the heat generation mechanism and the viscous dissipation due to an extensible sheet. The chemical reaction between the fluid particles and the fluid variable properties is assumed in this study. The motive behind this study is the continuous and great interest in the utilization of non-Newtonian liquids in organic and technical disciplines. This model is administered and governed by the momentum equation, energy equation, and concentration, all of which are in the form of partial differential equations. With the help of the shooting technique, the numerical solution is obtained. Graphs show the characteristics of flow, heat, and mass transfer mechanisms for various governing parameters. Additionally, significant physical non-dimensional quantities have been presented in a tabular form. The outcomes detect that increasing the Deborah number, which is connected with the mass transfer field and the chemical reaction parameter, decreases the concentration distribution.
An analysis is carried out to study the effects of temperature-dependent transport properties on the fully developed free and forced MHD convection flow in a vertical channel. In this model, viscous ...and Ohmic dissipation terms are also included. The governing nonlinear equations (in non-dimensional form) are solved numerically by a second order finite difference scheme. A parametric study is performed in order to illustrate the interactive influences of the model parameters; namely, the magnetic parameter, the variable viscosity parameter, the mixed convection parameter, the variable thermal conductivity parameter, the Brinkmann number and the Eckert number. The velocity field, the temperature field, the skin friction and the Nusselt number are evaluated for several sets of values of these parameters. For some special cases, the obtained numerical results are compared with the available results in the literature: Good agreement is found. Of all the parameters, the variable thermo-physical transport property has the strongest effect on the drag, heat transfer characteristics, the stream-wise velocity, and the temperature field.
The heat transfer characteristics of laminar single-phase forced convective water flow through a micro-tube heat exchanger are numerically investigated in this paper. Two-dimensional simulations are ...performed to find the effects of variable fluid properties on heat transfer for hydrodynamically and thermally developed flow. The effects of variable fluid properties on convective heat transfer coefficient (
h
) and Nusselt number (Nu) are significant for micro-convective flow. It is noted that the variation in temperature-dependent thermal conductivity
k
(
T
) greatly enhances the
h
as compared to the variation in temperature-dependent viscosity
µ
(
T
), although water viscosity–temperature sensitivity (
S
μT
) is greater than that of thermal conductivity–temperature sensitivity (
S
kT
). The effects of variation in wall heat flux (
q
w
″
) and inlet temperature on heat transfer are investigated for variable fluid properties. It is noted that the Nu declines with an augment in
q
w
″
for temperature-dependent density variation
ρ
(
T
). The Nu increases with an increase in
q
w
″
for
µ
(
T
) and
k
(
T
) variations. The results show that the Nu decreases with an increase in inlet temperature for variable fluid properties. The undevelopment and redevelopment of the flow are observed due to
µ
(
T
) variation. Additionally, the effects of wall heat flux, inlet temperature and inlet velocity on the variation of Nu/Pr
1/3
with Re are examined for
µ
(
T
) variation.
This paper put forward an analysis of variable fluid properties and their impact on hydromagnetic boundary and thermal layers in a quiescent fluid which is developed due to the exponentially ...stretching sheet. The viscous incompressible fluid has been set into motion due to aforementioned sheet. We assume that the viscosity and the thermal conductivity of the Newtonian fluid are temperature dependent. The governing boundary layer equations containing continuity, momentum and energy equations are coupled and nonlinear in nature, thereby, cannot be solvable easily by using analytical methods. Since the general boundary layer equations admits a similarity solutions, thus a generalized Howarth-Dorodnitsyn transformations have been exploited for the set-up of a coupled nonlinear ODEs. These transformed ODEs are solved numerically by a shooting method and is verified from MATLAB built-in collocation solver bvp4c for different parameters appearing in the work. We show results graphically and in a tabulated form for a constant and a variable fluid properties. We find that the temperature dependent variable viscosity and a thermal conductivity influence a velocity and a temperature profiles. We show that the thermal boundary layer decreases for constant variable fluid properties and increases for variable fluid properties
We present an analytical study which investigates the effect of temperature dependence in fluid properties on the interfacial instability of flow down a heated incline. Along with temperature ...variation in surface tension we consider variable mass density, viscosity, thermal conductivity and specific heat. A linear stability analysis is carried out which yields the critical conditions for the onset of instability in long-wave perturbations. Results are obtained for the particular case when there is variation only in surface tension, density and specific heat, and in the case with negligible and high rate of heat transfer across the free surface. For the general case, asymptotic expansions are implemented based on the assumed smallness of the variation with temperature in viscosity and thermal conductivity, or on weak heat transfer across the free surface.
In this paper, a wall-adapted anisotropic heat flux model for large eddy simulations of complex engineering applications is proposed. First, the accuracy and physical consistency of the novel heat ...flux model are testified for turbulent heated channel flows with different fluid properties by comparing with conventional isotropic models. Then, the performance of the model is evaluated in case of more complex heat and fluid flow situations that are in particular relevant for internal combustion engines and engine exhaust systems. For this purpose large eddy simulations of a strongly heated pipe flow, a turbulent inclined jet impinging on a heated solid surface and a backward-facing step flow with heated walls were carried out. It turned out that the proposed heat flux model has the following advantages over existing model formulations: (1) it accounts for variable fluid properties and anisotropic effects in the unresolved temperature scales, (2) no ad-hoc treatments or dynamic procedure are required to obtain the correct near-wall behavior, (3) the formulation is consistent with the second law of thermodynamics, and (4) the model has a similar prediction accuracy and computational effort than conventional isotropic models. In particular, it is shown that the proposed heat flux model is the only model under consideration that is able to predict the direction of subgrid-scale heat fluxes correctly, also under realistic heat and fluid flow conditions in complex engineering applications.
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