Stability Analysis of Unsteady Hybrid Nanofluid Flow Past a Permeable Stretching/Shrinking Cylinder

Abstract

The study of boundary layer flow has gained considerable interest owing to its extensive engineering applications. Thus, this numerical study aims to develop a mathematical hybrid nanofluid model and perform a stability analysis of unsteady flow in the hybrid Al2O3-Cu/H2O nanofluid past a permeable stretching/shrinking cylinder. The partial differential equations are converted into a system of nonlinear ordinary differential equations by selecting suitable similarity transformation and solved using the bvp4c code in the MATLAB program. The findings revealed that the existence of dual solutions is visible and successfully disclosed the fluid flow separation points. The skin friction coefficient and the local Nusselt numbers of Al2O3-Cu/H2O increase with the inclusion of the suction parameter, which consequently boosts the heat transfer efficiency. The coefficient of skin friction over the permeable stretching/shrinking cylinder is reduced when the unsteadiness parameter is diminished. In addition, the presence of the unsteadiness parameter actively promotes heat transfer degradation on the permeable stretching/shrinking cylinder. Stability analysis indicates that a stable and physically realizable solution appeared in the first solution, whereas the second solution is unstable.