Wake instability of viscoelastic flows past an unconfined inclined square cylinder

Abstract

A numerical study is presented to elucidate the characteristics of laminar viscoelastic shedding flow behind inclined square cylinders. The Giesekus model is used as the constitutive equation and governing equations were solved using a parallelized finite volume method. The CFD (Computational Fluid Dynamics) code was validated by comparing its results with published numerical and experimental data. The effects of angle of incidence, Reynolds number, Weissenberg number, polymer concentration, elasticity number, and also mobility factor are considered. Global quantities such as lift coefficient, Strouhal number, and the detailed kinetic variables like streamlines, shear stresses, and normal stress differences have been obtained in order to investigate the flow pattern of viscoelastic shedding flow. The Reynolds number is increased from Re = 60 to 120 for different angles of incidence. The computational results indicate that the flow is destabilized by increasing the Reynolds number or by increasing Weissenberg number. The computed results also indicate that the amplitude of the lift coefficient and shedding frequency are increased more strongly at higher polymer concentrations.