BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:MechE Colloquium: Bubble breakup in turbulence - From stochastic m
 odeling to linear stability analysis
DTSTART:20261013T120000
DTEND:20261013T130000
DTSTAMP:20261008T004353Z
UID:ca4c76bf7e8a30780acf3af56985cb031a62bca646668bed127d678b
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Alienor Rivère\, EPFL-LFMI\, Switzerland\nAbstract: \n\n
 In turbulent flows\, bubble fate is controlled by the ratio between inerti
 a and capillarity\, namely the Weber number. There exists a critical Weber
  number which separates\, on average\, breaking from non-breaking bubbles.
  However\, this limit is only defined in a statistical sense as an a prior
 i stable bubble can encounter a large velocity or pressure fluctuation and
  break. In addition\, real flows are rarely homogeneous and stationary. In
  this work\, we aim at quantifying the probability for a bubble to break 
 as a function of the time spent within the turbulence region and to ration
 alize the bubble breakup time.\n\nTo do so\, running direct numerical simu
 lations\, we first characterize the linear stochastic deformations of bubb
 les in homogeneous isotropic turbulence. We show that a 1D model describin
 g oblate/prolate deformations is sufficient to capture most of bubble defo
 rmations\, as well as predicting bubble lifetime provided the forcing stat
 istics and the bubble response are correctly parametrized. To further rati
 onalize the forcing statistics measured in the DNS\, we propose to decompo
 se the turbulent flow field into a sequence of elementary flows and to cha
 racterize bubble dynamics in each of them. We identify two main effective 
 flow candidates\, namely the uniaxial straining flow (USF) and the biaxial
  straining flow (BSF). While the first one has received considerable atten
 tion\, little is known on the dynamics of bubble in BSF. In this talk\, we
  present the linear stability analysis of bubble deformations in this flow
 . We enlighten surprising drift modes moving upstream as well as a new def
 ormation mode with azimuthal wave number m=2\, which might explain some of
  the breakage observed experimentally in turbulence.\n\n\n \n\nBio: \n\n
 Aliénor Rivière is an SNSF Fellow at the Laboratory of Fluid Mechanics a
 nd Instabilities (LFMI) at EPFL\, where she works with François Gallaire 
 on the stability and dynamics of bubbles in model flows. Her research in f
 luid dynamics focuses on multiphase flows and interfaces\, with an interse
 ction with dynamical systems and statistical physics. \n\nShe received an
  MSc in Physics from ENS Paris and an MSc in Fluid Mechanics from Sorbonne
  Université Paris. She obtained her PhD in Fluid Mechanics from ESPCI Par
 is in 2024\, with a thesis entitled Bubble Deformation and Fragmentation 
 in Turbulence\, supervised by Stéphane Perrard\, Laurent Duchemin\, and C
 hristophe Josserand.\n\nHer research has been recognized with the 2026 And
 reas Acrivos Dissertation Award of the American Physical Society\, the 202
 4 Grand Prix de thèse Daniel Guinier of the Société Française de Physi
 que\, the 2024 L’Oréal-UNESCO Young Talents Prize for Women in Science\
 , and the 2023 François Frenkiel Award from the APS Division of Fluid Dyn
 amics. Her work has been published in journals including the Journal of Fl
 uid Mechanics\, Physical Review Fluids\, and Physical Review Letters.\n
LOCATION:MED 0 1418 https://plan.epfl.ch/?room==MED%200%201418 https://epf
 l.zoom.us/j/61360740951
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR