Linear Stability Analysis for Plane-Poiseuille Flow of an Elastoviscoplastic fluid with internal microstructure

TL;DR

This paper analyzes the linear stability of plane-Poiseuille flow of an elastoviscoplastic fluid with microstructure, revealing how internal microstructure and elastic effects influence flow stability.

Contribution

It introduces a revised model for elastoviscoplastic fluids incorporating microstructure evolution and analyzes its stability characteristics.

Findings

Stability results align with pseudo-plastic fluid behavior.

Intermediate transition zone affects flow stability.

Elastic contributions modify the flow's stability properties.

Abstract

We study the linear stability of Plane Poiseuille flow of an elastoviscoplastic fluid using a revised version of the model proposed by Putz and Burghelea (Rheol. Acta (2009)48:673-689). The evolution of the microstructure upon a gradual increase of the external forcing is governed by a structural variable (the concentration of solid material elements) which decays smoothly from unity to zero as the stresses are gradually increased beyond the yield point. Stability results are in close conformity with the ones of a pseudo-plastic fluid. Destabilizing effects are related to the presence of an intermediate transition zone where elastic solid elements coexist with fluid elements. This region brings an elastic contribution which does modify the stability of the flow.