Paper Number
PO38
Session
Poster Session
Title
A complete rheological formalism built on the concept of recovery
Presentation Date and Time
October 13, 2021 (Wednesday) 6:30
Track / Room
Poster Session / Ballroom 1-2-3-4
Authors
- Shi, Jiachun (University of Illinois at Urbana-Champaign, Department of Chemical and Biomolecular Engineering)
- Rogers, Simon A. (University of Illinois at Urbana-Champaign, Department of Chemical and Biomolecular Engineering)
Author and Affiliation Lines
Jiachun Shi and Simon A. Rogers
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL
Speaker / Presenter
Shi, Jiachun
Keywords
experimental methods; theoretical methods; applied rheology; micelles; non-Newtonian fluids; rheology methods
Text of Abstract
Many rheological formalisms come from the concepts of inelastic fluid dynamics where deformations are always unrecoverable. We build a new formalism based on the ideas of recovery, which are ubiquitous in viscoelastic fluids. Our new formalism contains two contributions to arbitrary deformations, which therefore encompasses the traditional approach as a special case. The introduction of the two deformation gradients leads to two distinct measures of strain and strain rates, each based on recoverable or unrecoverable behaviors. The construction reveals the importance of performing recovery experiments and highlights the information gained from understanding the fundamental nature of those measurements. We performed transient nonlinear recovery measurements on a cetyl pyridinium chloride/sodium salicylate (CPCl/NaSal) solution, and the resultant rheological material functions allow the development of a new viscoelastic constitutive model, which consists of nonlinear viscous and elastic terms. We compare the model's predictions with the rheological measurements, and given the simplicity of the model, reasonably good agreements are found in the experimental data obtained from a range of different deformations. The present findings suggest a clear correlation exists between microstructural evolution and recoverable and unrecoverable components. A new direction is also provided to explore the relation between rheological material functions and material responses under different dynamic flows.