Low Reynolds number pulsatile flow of a viscoelastic fluid through a channel: Effects of fluid rheology and pulsation parameters

TL;DR

This study numerically investigates how fluid elasticity and pulsation parameters influence low Reynolds number pulsatile flow of viscoelastic fluids in channels, revealing flow enhancement and stress distribution patterns relevant to polymer processing.

Contribution

It introduces a numerical analysis of Oldroyd-B viscoelastic fluid flow under pulsatile conditions using OpenFOAM with a log-conformation tensor approach, highlighting effects of elasticity and pulsation.

Findings

Flow velocity increases with fluid elasticity.

High stress regions near the channel wall.

Velocity attenuation depends on pulsation parameters.

Abstract

As the first endeavour, we have analyzed the pulsatile flow of Oldroyd-B viscoelastic fluid where the combined effects of fluid elasticity and pulsation parameters on the flow characteristics are numerically studied at a low Reynolds number. Computations are performed using a finite-volume based open-source solver OpenFOAM by appending the log-conformation tensor approach to stabilize the numerical solution at high Deborah number. Significant flow velocity enhancement is achieved by increasing the viscoelastic behaviour of the fluid. High-velocity gradient zones and high polymeric stress regions are observed near the channel wall. The magnitude of axial velocity attenuates with increasing pulsation amplitude or pulsation frequency, and the extent of this attenuation is highly dependent on the Deborah number or the retardation ratio. This work finds application in the transport of polymeric solutions, extrusion, and injection moulding of polymer melts in several process industries.