Paper Number
IN14 

Session
Flow-induced Instabilities in Non-Newtonian Fluids

Title
Lagrangian stretching reveals polymeric stress field

Presentation Date and Time
October 12, 2022 (Wednesday) 1:50

Track / Room
Track 5 / Sheraton 2

Authors (Click on name to view author profile)

1. Kumar, Manish (Purdue University, School of Mechanical Engineering)
2. Ardekani, Arezoo (Purdue University, School of Mechanical Engineering)

Author and Affiliation Lines (in printed abstract book)
Manish Kumar and Arezoo Ardekani
School of Mechanical Engineering, Purdue University, West Lafayette, IN 47906

Speaker / Presenter 
Kumar, Manish

Keywords
theoretical methods; computational methods; flow-induced instabilities; polymer solutions

Text of Abstract
Viscoelastic flows are common in many natural and industrial applications such as biofilm transport, drug delivery, and enhanced oil recovery. The stretching of polymeric chains in viscoelastic flows induces elastic instability, which manifests into symmetry-breaking, time-dependent flows and anomalous transport properties. The knowledge of the polymeric stress field is essential for understanding transport in viscoelastic flows because the topology of the polymeric stress field controls the flow states and dynamics in viscoelastic flows. However, the experimental measurements of the stress field are challenging. We obtain a relationship between the polymeric stress field and the Lagrangian stretching field through analytical and numerical analyses. The Lagrangian stretching field depends solely on the flow kinematics, which is relatively easy to measure in the experiment. Thus, our result establishes a simple framework to unveil the topology of the polymeric stress field directly from readily measurable flow field data, even for strongly viscoelastic and unstable flows.