Stagnation point flow toward an exponentially shrinking sheet in a hybrid nanofluid. Issue 3 (3rd July 2021)

• Record Type: Journal Article
• Authors: Waini, Iskandar; Pop, Ioan; Abu Bakar, Sakhinah; Ishak, Anuar
• Is Part Of: International journal of numerical methods for heat & fluid flow. Volume 32:Issue 3(2022)
• Page Start: 1012
• Page End: 1024
• Publication Date: 2021-07-03
• Subjects: Stability analysis -- Dual solutions -- Shrinking sheet -- MHD -- Hybrid nanofluid -- Bvp4c -- Stagnation point; Heat -- Transmission -- Mathematics -- Periodicals; Fluid dynamics -- Mathematics -- Periodicals; 536.2
• DOI: 10.1108/HFF-01-2021-0039
• Languages: English
• ISSNs: 0961-5539

Abstract

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-Al2 O3 /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.