Mixed Convection in Unsteady Stagnation Point Flow of Maxwell Fluid Subject to Modified Fourier’s Law

2020 ◽  
Vol 45 (11) ◽  
pp. 9439-9447 ◽  
Author(s):  
Awais Ahmed ◽  
Masood Khan ◽  
Jawad Ahmed ◽  
Sohail Nadeem
2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Fayeza Al Sulti

Stagnation-point flow toward a stretching sheet with slip effects has been investigated. Unlike most classical works, Cattaneo–Christov heat flux model is utilized for the formulation of the energy equation instead of Fourier's law of heat conduction. A similarity transformation technique is adopted to reduce partial differential equations into a system of nonlinear ordinary differential equations. Numerical solutions are obtained by using shooting method to explore the features of various parameters for the velocity and temperature distributions. The obtained results are graphically presented and analyzed. It is found that fluid temperature has a converse relationship with the thermal relaxation time. A comparison of Cattaneo–Christov heat flux model and Fourier's law is also presented.


2014 ◽  
Vol 10 (2) ◽  
pp. 60-68
Author(s):  
Kotha Gangadhar ◽  
◽  
Thommaandru RangaRao ◽  
M. J. Subhakar ◽  
T.V.S. Sekhar

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yu Bai ◽  
Lamei Huo ◽  
Yan Zhang

Purpose The purpose of this study is to investigate the unsteady stagnation-point flow and heat transfer of fractional Maxwell fluid towards a time power-law-dependent stretching plate. Based on the characteristics of pressure in the boundary layer, the momentum equation with the fractional Maxwell model is firstly formulated to analyze unsteady stagnation-point flow. Furthermore, generalized Fourier’s law is considered in the energy equation and boundary condition of convective heat transfer. Design/methodology/approach The nonlinear fractional differential equations are solved by the newly developed finite difference scheme combined with L1-algorithm, whose convergence is verified by constructing a numerical example. Findings Some interesting results can be revealed. The larger fractional derivative parameter of velocity promotes the flow, while the smaller fractional derivative parameter of temperature accelerates the heat transfer. The temperature boundary layer is thicker than the velocity boundary layer, and the velocity enlarges as the stagnation parameter raises. This is because when Prandtl number < 1, the capacity of heat diffusion is greater than that of momentum diffusion. It is to be observed that all the temperature profiles first enhance a little and then reduce rapidly, which indicates the thermal retardation of Maxwell fluid. Originality/value The unsteady stagnation-point flow model of Maxwell fluid is extended from integral derivative to fractional derivative, which has more flexibility to describe viscoelastic fluid’s complex dynamic process and provide a theoretical basis for industrial processing.


2021 ◽  
Author(s):  
Yu Bai ◽  
Sa Wan ◽  
Yan Zhang

Abstract The aim of the article is to research the unsteady magnetohydrodynamic stagnation-point flow of fractional Oldroyd-B fluid over a stretched sheet. According to the distribution characteristics of pressure and magnetic field near the stagnation point, the momentum equation based on fractional Oldroyd-B constitutive model is derived. Moreover, the modified fractional Fourier's law considering thermal relaxation-retardation time is proposed, which applies in both the energy equation and the boundary condition of convective heat transfer. New finite difference scheme combined with L1 algorithm is established to solve the governing equations, whose convergence is confirmed by constructing the exact solution. The results indicate that the larger relaxation parameters of velocity block the flow, yet the retardation parameters of velocity show the opposite trend. It is particularly worth mentioning that all the temperature profiles first go up slightly to a maximal value and then descend markedly, which presents the thermal retardation characteristic of Oldroyd-B fluid. Additionally, under the effects of temperature's retardation and relaxation parameters, the intersection of the profiles far away from stretching sheet demonstrates the thermal memory characteristic.


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