Paper Number
GR9 

Session
Gallery of Rheology Contest

Title
Transition to turbulence in planar jets: Small amounts of polymer destabilize the flow

Presentation Date and Time
October 13, 2021 (Wednesday) 6:30

Track / Room
Gallery of Rheology / Ballroom Pre Function

Authors (Click on name to view author profile)

1. Yamanidouzisorkhabi, Sami (Massachusetts Institute of Technology, Mechanical Engineering)
2. Raj, Yashasvi (Massachusetts Institute of Technology, Mechanical Engineering)
3. McKinley, Gareth H. (Massachusetts Institute of Technology, Mechanical Engineering)
4. Bischofberger, Irmgard (Massachusetts Institute of Technology, Mechanical Engineering)

Author and Affiliation Lines (in printed abstract book)
Sami Yamanidouzisorkhabi, Yashasvi Raj, Gareth H. McKinley and Irmgard Bischofberger
Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139

Speaker / Presenter 
Yamanidouzisorkhabi, Sami

Keywords
flow-induced instabilities; non-Newtonian fluids; polymer solutions

Text of Abstract
We use high-speed digital Schlieren imaging to visualize the evolution of Lagrangian flow structures in planar jets entering a quiescent bath of water. The jets have an aspect ratio of 10 at the nozzle; their width is 4 mm and their thickness is 0.4 mm. We investigate the transition to turbulence in jets of water (Newtonian case) and in jets of dilute aqueous polymer solutions (viscoelastic case). For the Newtonian jets, the development of a shear layer instability at the edges of the jet leads to vortex roll up and ultimately to turbulence. A unique inertio-elastic instability at the center of the viscoelastic jets leads to a transition to turbulence at a lower Reynolds number compared to that characterizing the transition for Newtonian jets.