Impact of anisotropic slip on the stagnation-point flow past a stretching/shrinking surface of the Al2O3-Cu/H2O hybrid nanofluid

2020 ◽  
Vol 41 (9) ◽  
pp. 1401-1416
Author(s):  
N. A. Zainal ◽  
R. Nazar ◽  
K. Naganthran ◽  
I. Pop
Keyword(s):  
Stagnation Point ◽  
Stagnation Point Flow ◽  
Hybrid Nanofluid ◽  
Flow Past ◽  
Shrinking Surface

MHD stagnation point flow on a shrinking surface with hybrid nanoparticles and melting phenomenon effects

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ioan Pop ◽  
Iskandar Waini ◽  
Anuar Ishak
Keyword(s):  
Stagnation Point ◽  
Temporal Stability ◽  
Dual Solutions ◽  
Stagnation Point Flow ◽  
Heat Transfer Analysis ◽  
Physical Parameters ◽  
Hybrid Nanofluid ◽  
Content Type ◽  
Melting Phenomenon ◽  
Shrinking Surface

Purpose This study aims to explore the stagnation flow over a shrinking surface in a hybrid nanofluid consists of Al2O3 and Cu nanoparticles. Here, the flow is subjected to the magnetohydrodynamic (MHD) and the melting phenomenon effects. Design/methodology/approach The similarity variables are used to gain the similarity equations. These equations are solved via the bvp4c solver. The effects of several physical parameters on the flow and the thermal characteristics of the hybrid nanofluid are analysed and discussed. Later, the temporal stability analysis is used to determine the stability of the dual solutions obtained as time evolves. Findings Results show that two solutions are found for the limited range of the stretching/shrinking parameter λ, and then these solutions are terminated at λ=λc. The rise of the melting parameter Me from 0 to 2 contributes to enhance 109.63% of the local Nusselt number Rex-1/2Nux and 3.30% of the skin friction coefficient Rex1/2Cf. Contrarily, the values of Rex-1/2Nux and Rex1/2Cf decline by 25.04% and 5.58%, respectively, as the magnetic parameter Mg increases from 0 to 0.3. Additionally, Al2O3-Cu/water has the highest values of Rex1/2Cf and the lowest values of Rex-1/2Nux. Lastly, it is found that the first solution is physically stable as time evolves. Originality/value This paper considers the MHD stagnation point flow of a hybrid nanofluid over a shrinking surface with the melting phenomenon effects. Most importantly, it is shown that there exist dual solutions within a specific range of the physical parameters. Besides, the temporal stability of the solutions is also reported in this study. The finding can contribute to foresee the flow and thermal behaviours in industrial applications. Also, the suitable values of parameters can be determined to avoid misjudgement in flow and heat transfer analysis.

scholarly journals Oblique Stagnation-Point Flow Past a Shrinking Surface in a Cu-Al2O3/H2O Hybrid Nanofluid

2021 ◽  
Vol 50 (10) ◽  
pp. 3139-3152
Author(s):  
Rusya Iryanti Yahaya ◽  
Norihan Md Arifin ◽  
Roslinda Mohd. Nazar ◽  
Ioan Pop
Keyword(s):  
Skin Friction ◽  
Stagnation Point ◽  
Numerical Solutions ◽  
Similarity Transformation ◽  
Skin Friction Coefficient ◽  
Stagnation Point Flow ◽  
Hybrid Nanofluid ◽  
Al2o3 Nanoparticles ◽  
Oblique Flow ◽  
Shrinking Surface

To fill the existing literature gap, the numerical solutions for the oblique stagnation-point flow of Cu-Al2O3/H2O hybrid nanofluid past a shrinking surface are computed and analyzed. The computation, using similarity transformation and bvp4c solver, results in dual solutions. Stability analysis then shows that the first solution is stable with positive smallest eigenvalues. Besides that, the addition of Al2O3 nanoparticles into the Cu-H2O nanofluid is found to reduce the skin friction coefficient by 37.753% while enhances the local Nusselt number by 4.798%. The increase in the shrinking parameter reduces the velocity profile but increases the temperature profile of the hybrid nanofluid. Meanwhile, the increase in the free parameter related to the shear flow reduces the oblique flow skin friction.

MHD oblique stagnation-point flow towards a stretching/shrinking surface

Meccanica ◽  
2015 ◽  
Vol 50 (12) ◽  
pp. 2949-2961 ◽  
Author(s):  
Y. Y. Lok ◽  
J. H. Merkin ◽  
I. Pop
Keyword(s):  
Stagnation Point ◽  
Stagnation Point Flow ◽  
Shrinking Surface

Numerical solutions of non-alignment stagnation-point flow and heat transfer over a stretching/shrinking surface in a nanofluid

2016 ◽  
Vol 26 (6) ◽  
pp. 1747-1767 ◽  
Author(s):  
Ioan Pop ◽  
Kohi Naganthran ◽  
Roslinda Nazar
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Stagnation Point ◽  
Numerical Solutions ◽  
Dual Solutions ◽  
Stagnation Point Flow ◽  
Content Type ◽  
Boundary Layer Equations ◽  
Flow And Heat Transfer ◽  
Shrinking Surface

Purpose – The purpose of this paper is to analyse numerically the steady stagnation-point flow of a viscous and incompressible fluid over continuously non-aligned stretching or shrinking surface in its own plane in a water-based nanofluid which contains three different types of nanoparticles, namely, Cu, Al2O3 and TiO2. Design/methodology/approach – Similarity transformation is used to convert the system of boundary layer equations which are in the form of partial differential equations into a system of ordinary differential equations. The system of similarity governing equations is then reduced to a system of first-order differential equations and solved numerically using the bvp4c function in Matlab software. Findings – Unique solution exists when the surface is stretched and dual solutions exist as the surface shrunk. For the dual solutions, stability analysis has revealed that the first solution (upper branch) is stable and physically realizable, while the second solution (lower branch) is unstable. The effect of non-alignment is huge for the shrinking surface which is in contrast with the stretching surface. Practical implications – The results obtained can be used to explain the characteristics and applications of nanofluids, which are widely used as coolants, lubricants, heat exchangers and micro-channel heat sinks. This problem also applies to some situations such as materials which are manufactured by extrusion, production of glass-fibre and shrinking balloon. In this kind of circumstance, the rate of cooling and the stretching/shrinking process play an important role in moulding the final product according to preferable features. Originality/value – The present results are original and new for the study of fluid flow and heat transfer over a stretching/shrinking surface for the problem considered by Wang (2008) in a viscous fluid and extends to nanofluid by using the Tiwari and Das (2007) model.

scholarly journals Fractional order stagnation point flow of the hybrid nanofluid towards a stretching sheet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anwar Saeed ◽  
Muhammad Bilal ◽  
Taza Gul ◽  
Poom Kumam ◽  
Amir Khan ◽  
...  
Keyword(s):  
Stagnation Point ◽  
Fractional Order ◽  
Transition Rate ◽  
Stretching Sheet ◽  
Stagnation Point Flow ◽  
Hybrid Nanofluid ◽  
Fractional Order Differential Equations ◽  
Classical Calculus ◽  
Electric And Magnetic Fields ◽  
Heat Transition

AbstractFractional calculus characterizes a function at those points, where classical calculus failed. In the current study, we explored the fractional behavior of the stagnation point flow of hybrid nano liquid consisting of TiO2 and Ag nanoparticles across a stretching sheet. Silver Ag and Titanium dioxide TiO2 nanocomposites are one of the most significant and fascinating nanocomposites perform an important role in nanobiotechnology, especially in nanomedicine and for cancer cell therapy since these metal nanoparticles are thought to improve photocatalytic operation. The fluid movement over a stretching layer is subjected to electric and magnetic fields. The problem has been formulated in the form of the system of PDEs, which are reduced to the system of fractional-order ODEs by implementing the fractional similarity framework. The obtained fractional order differential equations are further solved via fractional code FDE-12 based on Caputo derivative. It has been perceived that the drifting velocity generated by the electric field E significantly improves the velocity and heat transition rate of blood. The fractional model is more generalized and applicable than the classical one.

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