Paper Number
NF5 

Session
Non-Newtonian Fluid Mechanics & Instabilities

Title
Color interferometry applied to yield-stress fluid drop impacts on heated surfaces

Presentation Date and Time
February 14, 2017 (Tuesday) 5:15

Track / Room
Track 2 / Audubon A

Authors (Click on name to view author profile)

1. Blackwell, Brendan C. (University of Illinois at Urbana-Champaign, Mechanical Science & Engineering)
2. Wu, Alex (University of Illinois at Urbana-Champaign)
3. Sarvaiya, Mrunal J. (University of Illinois at Urbana-Champaign)
4. Ewoldt, Randy H. (University of Illinois at Urbana-Champaign, Mechanical Science and Engineering)

Author and Affiliation Lines (in printed abstract book)
Brendan C. Blackwell¹, Alex Wu², Mrunal J. Sarvaiya², and Randy H. Ewoldt^1
1Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801; ²University of Illinois at Urbana-Champaign, Urbana, IL 61801

Speaker / Presenter 
Blackwell, Brendan C.

Text of Abstract
Yield-stress fluids, including gels and pastes, are effectively fluid at high stress and solid at low stress. In liquid-solid impacts, these fluids can stick and accumulate where they impact, motivating several applications of these rheologically-complex materials. Here we use high-speed imaging and color interferometry to experimentally study liquid-solid impact of yield-stress fluids on heated surfaces. Aqueous materials tend to adhere at to a surface low temperature and release at high temperature; our prior work showed that increasing the yield stress decreases the temperature required to prevent material from sticking. Here we present videos captured using interferometry to observe the thickness of the vapor layer between the drop and the surface during both stick and non-stick events. We use these data to gain insight into the physics behind the phenomenon of the yield stress reducing sticking to hot surfaces.