Numerical study of unsteady viscoelastic flow past two side-by-side circular cylinders

Abstract

In this study, numerical simulation is conducted to understand the two-dimensional viscoelastic flows past two side-by-side circular cylinders at a Reynolds number of 100. The Peterlin approximation of the finitely extensible nonlinear elastic model is adopted to describe the non-linear modulus of elasticity and the finite extendibility of polymer macromolecules. The flow behavior and time-averaged forces that act on the two cylinders are investigated over a wide range of parameter space, i.e., the Weissenberg number (We), from 0 to 8, and the spacing between the two cylinders (LD), from 0.1D to 3.0D (D denotes the diameter of each cylinder). Similar to the corresponding Newtonian flow, the viscoelastic flow gradually undergoes six transitions as LD increases. However, these transitions are delayed in the viscoelastic flow, particularly at a high We. As a result, three distinct flow modes remain within the above-mentioned LD range at a high We. With increasing We, the total drag acting on the two cylinders increases for all LD values, and the repulsive force between the two cylinders gradually decreases for a lower LD value but increases for a higher LD value. Both the intensity and frequency of force fluctuation decrease as We increases. The findings of the present study may provide new insight into the multi-body wake dynamics in the viscoelastic flow.