Mansoor Hakimollahi - Automobile Engineering Department, Iran University of Science and Technology and head of science and technology department of Ahlul Bayt International University, Tehran, Iran
Hasan Athari - Mechanical engineering Department, University college of science and technology (Elm-o-fann), Urmia, Iran

In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like water, resist shear flow and strain linearly with time when stress is applied. Elastic materials strain when stretched and immediately return to their original state once the stress is removed. Viscoelastic materials have elements of both of these properties and, as such, exhibit time-dependent strain. Present work is a numerical study of viscoelastic fluid flow around a cylinder. This work is a two-dimensional simulation and the aspect ratio of the cylinder radius to the channel half-width was ۰.۵. In this study, the Weissenberg number (Wi) plays a key role. This number is dimensionless that compares the elastic forces to the viscous forces. It can be variously defined, but it is usually given by the relation of stress relaxation time of the fluid and a specific process time. The achieved results demonstrate that when the Wi number increases, the viscoelastic stress goes up, too. Also, it is found that the velocity is independent of the Wi number. The drag coefficient graph shows that the drag coefficient in the front zone of the cylinder is very high and the trend of the graph is descending.

Viscoelastic flow; Oldroyd-B fluid; Cylinder; CFD