Rheological transient effects on steady-state contraction flows

Abstract

It may be assumed that the steady-state kinematics of viscoelastic contraction flows depends on the time-independent rheological properties only. This idea is supported by the large number of references explaining steady simulation results by considering only steady-state material functions. Even with numerical simulations, it would be difficult to prove such a statement wrong. However, using the Bautista-Manero-Puig class of models allows to obtain the same steady rheological response but with different transient evolution. Here, we considered two fluids, one displaying a monotonic trend towards the steady-state and the other with at least one visible overshoot in the material functions. Our results show that for the transient evolution with the overshoot fluid, a significant increase in the steady pressure drop is gathered. In addition, vortex response is quite different for the two fluids. This research gives evidence that the transient evolution in rheometrical functions has great impact on steady-state flow behavior.