Abstract
We investigated influence of viscoelasticity on turbulent backward-facing step flow at low Reynolds number using direct numerical simulation (DNS). In this study, Newtonian fluid and viscoelastic fluids (Wi_<τ0>=10, 20) were calculated at a friction Reynolds number Re_<τ0>=100. The geometry of the flow channel is that having an upper wall and a step with the expansion ratio of ER=1.5. The reattachment length X_r/h (h: step height) from the step is 6.80, 7.82 and 8.82 for Newtonian, Wi_<τ0>=10 and Wi_<τ0>=20, respectively. For instantaneous fields, the amount of vortices emerging at separated shares layer decreases with the increasing Wi_<τ0>. For averaged fields, while u'rms near the separated share layer decreases as Wi_<τ0> increases, that near the upper wall increases as Wi_<τ0> increases. This result may be caused by the separating of mainstream from the upper wall.
