Hybrid nanofluid flow on a shrinking cylinder with prescribed surface heat flux

Purpose This study aims to investigate the flow impinging on a stagnation point of a shrinking cylinder subjected to prescribed surface heat flux in Al2O3-Cu/water hybrid nanofluid. Design/methodology/approach Using similarity variables, the similarity equations are obtained and then solved using bvp4c in MATLAB. The effects of several physical parameters on the skin friction and heat transfer rate, as well as the velocity and temperature profiles are analysed and discussed. Findings The outcomes show that dual solutions are possible for the shrinking case, in the range lambda(c)<lambda<-1, where lambda(c) is the bifurcation point of the solutions. Meanwhile, the solution is unique for lambda >=-1. Besides, the boundary layer is detached on the surface at lambda c, where the value of lambda cis affected by the hybrid nanoparticle phi hnfand the curvature parameter gamma. Moreover, the friction and the heat transfer on the surface increase with the rising values phi hnfand gamma. Finally, the temporal stability analysis shows that the first solution is stable in the long run, whereas the second solution is not. Originality/value The present work considers the problem of stagnation point flow impinging on a shrinking cylinder containing Al2O3-Cu/water hybrid nanofluid, with prescribed surface heat flux. This paper shows that two solutions are obtained for the shrinking case. Further analysis shows that only one of the solutions is stable as time evolves.