Published on June 27, 2023
–
Updated on June 27, 2023
Dates
on the June 30, 2023
10:00: coffee
10:15: seminar
10:15: seminar
Location
Institut de Physique de Nice
Nonlinear dynamics of confined soft objects : from oil in porous media to tree embolism
Seminars of the Institut de Physique de Nice
Spring 2023: new permanent members
Abstract:
After a brief description of my curriculum, I will present two different
studies involving the transport of drops and bubbles in confined
environments where peculiar nonlinear dynamics are observed.
The first study is related to the transport of viscous oil drops in
confined media, of primary importance for industrial processes such as
oil recovery or underground C02 storage. When a non-wetting and highly
viscous oil droplet moves in a confined microchannel, viscous
dissipation is mainly located in a thin lubricating film isolating the
drop from the walls and amplifying its mobility [1]. I will show how the
introduction of roughness on the surface of the walls can dramatically
alter the dynamics of the drop and substantially decrease its mobility
by orders of magnitude. The transition between those two dissipation
modes is sharp and drops can jump from one state to the other by
slightly modifying the experiment parameters [2]. I will then discuss
how this roughness-induced dissipation transition can open perspectives
for the manipulation of a wide class of soft objects such as capsules,
vesicles, or living cells.
The second study is related to air embolism formation in plants and
trees. Global warming will lead to increasingly severe droughts and
threatens most of the forests in the world [3]. One of the main dangers
of droughts for trees comes from the generation of air embolism, which
impairs sap conduction and potentially leads to their death. In leaves,
embolism formation is jerky and exhibits catastrophic events [4]. By
using PDMS-based biomimetic leaves to reproduce evapotranspiration, we
show that introducing narrow constrictions in the veins enables us to
recover an intermittent embolism propagation [5]. I will finally present
promising perspectives opened by the validation of our leaf-on-a-chip.
References :
[1] Keiser, L., Jaafar, K., Bico, J., & Reyssat, E. (2018). Dynamics of
non-wetting drops confined in a Hele-Shaw cell. Journal of Fluid
Mechanics, 845, 245-262.
[2] Keiser, L., Keiser, A., L’estimé, M., Bico, J., & Reyssat, É.
(2019). Motion of viscous droplets in rough confinement: paradoxical
lubrication. Physical review letters, 122(7), 074501.
[3] Brodribb, T. J., Powers, J., Cochard, H., & Choat, B. (2020).
Hanging by a thread? Forests and drought. Science, 368(6488), 261-266.
[4] Brodribb, T. J., Bienaimé, D., & Marmottant, P. (2016). Revealing
catastrophic failure of leaf networks under stress. Proceedings of the
National Academy of Sciences, 113(17), 4865-4869.
[5] Keiser, L., Marmottant, P., & Dollet, B. (2022). Intermittent air
invasion in pervaporating compliant microchannels. Journal of Fluid
Mechanics, 948, A52
Spring 2023: new permanent members
Abstract:
After a brief description of my curriculum, I will present two different
studies involving the transport of drops and bubbles in confined
environments where peculiar nonlinear dynamics are observed.
The first study is related to the transport of viscous oil drops in
confined media, of primary importance for industrial processes such as
oil recovery or underground C02 storage. When a non-wetting and highly
viscous oil droplet moves in a confined microchannel, viscous
dissipation is mainly located in a thin lubricating film isolating the
drop from the walls and amplifying its mobility [1]. I will show how the
introduction of roughness on the surface of the walls can dramatically
alter the dynamics of the drop and substantially decrease its mobility
by orders of magnitude. The transition between those two dissipation
modes is sharp and drops can jump from one state to the other by
slightly modifying the experiment parameters [2]. I will then discuss
how this roughness-induced dissipation transition can open perspectives
for the manipulation of a wide class of soft objects such as capsules,
vesicles, or living cells.
The second study is related to air embolism formation in plants and
trees. Global warming will lead to increasingly severe droughts and
threatens most of the forests in the world [3]. One of the main dangers
of droughts for trees comes from the generation of air embolism, which
impairs sap conduction and potentially leads to their death. In leaves,
embolism formation is jerky and exhibits catastrophic events [4]. By
using PDMS-based biomimetic leaves to reproduce evapotranspiration, we
show that introducing narrow constrictions in the veins enables us to
recover an intermittent embolism propagation [5]. I will finally present
promising perspectives opened by the validation of our leaf-on-a-chip.
References :
[1] Keiser, L., Jaafar, K., Bico, J., & Reyssat, E. (2018). Dynamics of
non-wetting drops confined in a Hele-Shaw cell. Journal of Fluid
Mechanics, 845, 245-262.
[2] Keiser, L., Keiser, A., L’estimé, M., Bico, J., & Reyssat, É.
(2019). Motion of viscous droplets in rough confinement: paradoxical
lubrication. Physical review letters, 122(7), 074501.
[3] Brodribb, T. J., Powers, J., Cochard, H., & Choat, B. (2020).
Hanging by a thread? Forests and drought. Science, 368(6488), 261-266.
[4] Brodribb, T. J., Bienaimé, D., & Marmottant, P. (2016). Revealing
catastrophic failure of leaf networks under stress. Proceedings of the
National Academy of Sciences, 113(17), 4865-4869.
[5] Keiser, L., Marmottant, P., & Dollet, B. (2022). Intermittent air
invasion in pervaporating compliant microchannels. Journal of Fluid
Mechanics, 948, A52
