Numerical Analysis of Thermofluidic Transport of Viscoelastic Fluid Around a Circular Cylinder

A two-dimensional numerical analysis is carried out to analyze the thermofluidic transport characteristics of a viscoelastic fluid past a circular cylinder. The numerical simulation is performed through the commercial solver Ansys Fluent. The Oldroyd-B constitutive model is adopted to describe the viscoelastic behavior. The viscoelastic constitutive equations are embedded into the Fluent code through the "user defined functionality" of the solver for the numerical calculations of polymer stresses. The roles of the viscoelasticity and the forced convective heat transfer are studied for the range of Weissenberg number (0–7), for a fixed Prandtl number 50 and Reynolds number 10–40. It is observed that the wake behind the cylinder increases in both the lateral and the longitudinal directions with increase of Weissenberg number. The recirculating wake starts suppressing with further increase of Weissenberg number and at a critical Weissenberg number, the wake vanishes completely resulting an attached flow with the cylinder. The critical Weissenberg number is found to increase with Reynolds number. It is also found that the recirculating wake breaks into a pair of symmetric vortices at some intermediate value of Weissenberg number for Reynolds number greater than 20. The increase of the wake size is more in case of higher Reynolds number. The average Nusselt number increases with Reynolds number, whereas it decreases with increasing Weissenberg number. Heat transfer reduction and drag enhancement are observed with elastic effects.