Stagnation point flow toward an exponentially shrinking sheet in a hybrid nanofluid
International Journal of Numerical Methods for Heat & Fluid Flow
ISSN: 0961-5539
Article publication date: 3 July 2021
Issue publication date: 20 January 2022
Abstract
Purpose
This paper aims to investigate the radiation and magnetohydrodynamic effect on the flow toward a stagnation point of an exponentially shrinking sheet in a hybrid nanofluid.
Design/methodology/approach
The governing partial differential equations are transformed into a set of similarity equations and are then solved numerically using the boundary value problem solver, bvp4c, available in MATLAB software. The effects of several physical parameters on the flow and the thermal characteristics of the hybrid nanofluid are analyzed and discussed.
Findings
Numerical results clarify that the dual solutions arise for the shrinking case (λ < 0). The critical values expand for the stronger magnetic field. Besides, the skin friction and the heat transfer coefficients enhance with the rise of the magnetic field and the hybrid nanoparticles. The heat transfer rate increases by 10.11% for the nanofluid and 28.69% for the hybrid nanofluid compared to the regular fluid. In addition, the presence of radiation gives a higher heat transfer rate. Using the stability analysis, it is found that the first solution is stable, and the second solution is unstable, over time.
Originality/value
The stagnation point flow problem has been widely studied for the flow over a stretching sheet, but only limited findings can be found for the flow over a shrinking sheet. Therefore, the present study considers the problem of the stagnation point flow over a shrinking sheet in a Cu-Al2O3/water hybrid nanofluid with the effects of magnetic field and thermal radiation. The dual solutions of the hybrid nanofluid flow over a shrinking sheet are obtained. Further analysis shows that only one of the solutions is stable and thus physically reliable as time evolves.
Keywords
Acknowledgements
The authors wish to express their thanks to the anonymous reviewers for their valuable comments and suggestions. The financial supports received from the Universiti Kebangsaan Malaysia (Project Code: DIP-2020–001) and the Universiti Teknikal Malaysia Melaka are gratefully acknowledged.
Competing interests: The authors declare no competing interests.
Citation
Waini, I., Pop, I., Abu Bakar, S. and Ishak, A. (2022), "Stagnation point flow toward an exponentially shrinking sheet in a hybrid nanofluid", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 32 No. 3, pp. 1012-1024. https://doi.org/10.1108/HFF-01-2021-0039
Publisher
:Emerald Publishing Limited
Copyright © 2021, Emerald Publishing Limited