MHD oblique stagnation point flow of nanofluid over an oscillatory stretching/shrinking sheet: existence of dual solutions

Abstract

An unsteady magnetohydrodynamic oblique stagnation point flow of an incompressible nanofluid towards a stretching/shrinking surface with the effect of mass suction on the oscillatory surface is analyzed. Water is considered as a base fluid while single wall carbon nanotubes are assumed as nanoparticles. The governing flow equations are transformed into a system of coupled nonlinear ordinary differential equations via suitable transformation. Dual solutions of these nonlinear coupled equations are obtained by utilizing the bvp4c package in MATLAB. It is also found that these solutions survive in a certain domain of controlling parameters. The physical influence of several controlling parameters like nanoparticle volume fraction parameter, Hartmann number, stretching/shrinking parameter and suction parameter on heat transfer characteristics and flow field are discussed in detail and are demonstrated through graphs. We find that dual solutions exist in both the stretching case and the shrinking case. Also, the lower solution branch shows singular behavior for the skin friction coefficient in the shrinking domain whereas the upper solution branch has smooth behavior in both the stretching and shrinking domains.