Séminar by Marie Tani (Tokyo Metropolitan University)
Published on September 5, 2023
–
Updated on September 5, 2023
Dates
on the September 7, 2023
2pm
Location
Institut de Physique de Nice
Conference room n°3 - 3rd floor.
How can we spread a liquid foam on a substrate?
Abstract:
Liquid foam is ubiquitous in our everyday life, such as foods,
beverages, detergents and cosmetics. Although foam consists only of
liquid and air bubbles, it has a variety of unique properties. For
example, foam exhibits some elastic response to weak stress and weak
strain, but to large strain, foam deforms and flows macroscopically with
rearrangements of air bubbles. These macroscopic behaviors can be
observed when washing the bodies or dishes. While this is a common
situation and the dynamics and mechanism of the spreading of liquid on a
substrate have been studied for decades, that of foam has not yet been
clarified.
Here, we focus on how a foam is spread by a rigid plate on a low
wettable substrate. Differently from simple liquid cases, three
distinguishable spreading patterns were observed with increasing the
spreading velocity: homogeneous spreading (pattern 1), non-spreading
(pattern 2), and slender spreading (pattern 3). We fabricated the
spreading pattern diagram from experiments where the gap height,
confinement length, amount of the foam, and wettability of the substrate
were independently varied. Furthermore, we succeed to describe the
border between patterns 1 and 2 theoretically.
In this talk, we will show the dynamics of each pattern and theoretical
approach to elucidate the dynamics and the borders between patterns.
*This work is done with Masaya Endo and Rei Kurita.
Hosted by Ludovic Keiser
