Numerical exploration of buoyancy inspired flow of pseudoplastic fluid along a vertical cylinder with viscous dissipation effects

Abstract

This research presents a numerical investigation for flow around a stagnation point on a vertical stretching cylinder placed in a pseudo-plastic fluid. An important Carreau fluid model is adopted to account for pseudo-plastic effects in the flow field. Buoyancy force term arising due to the vertical boundary is formulated under the well-known Oberbeck-Boussinesq approximation. Conservation equations simplified under boundary layer assumptions are solved for the similarity solutions for full range of parameter A, giving the ratio of free stream velocity to the cylinder surface velocity. The shape of velocity profile is dependent on the choice of the parameter A. Contributions of buoyancy force term and shear-thinning effect in both assisting and opposing flow situations are scrutinized. A striking influence of rheology is such that resisting wall shear declines and cooling rate of the surface drops whenever shear-thinning effect is present. However, cooling rate amplifies as the strength of buoyancy force is enhanced. Special cases of the model including the case of flat surface and Newtonian fluid are presented separately.

Keywords

• Carreau fluid
• Buoyancy force
• Apparent viscosity
• Stagnation-point flow
• Cylindrical surface