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SUMMARY:MechE Seminar : Bubble deformations and breakup in a turbulent flo
 w
DTSTART:20240523T140000
DTEND:20240523T150000
DTSTAMP:20260525T071601Z
UID:36a7494181c46732b4d74e1150c149178e163b6c5cd3c41378cd831f
CATEGORIES:Conferences - Seminars
DESCRIPTION:Aliénor Rivière\nAbstract:\nIn turbulent flows\, bubble fate
  is controlled by the ratio between inertia and capillarity\, namely the W
 eber number. There exists a critical Weber number which separates\, in ave
 rage\, breaking from non-breaking bubbles. However\, this limit is only de
 fined in a statistical sense as it can happen that an a priori stable bubb
 le encounters a large velocity or pressure fluctuation and breaks. In addi
 tion\, real flows are rarely homogeneous and stationary. Using numerical s
 imulations\, we aim at quantifying the probability for a bubble to break i
 n a given time window. To do so\, we first study bubble deformations in a 
 simplified flow geometry representative of the local flow geometry around 
 bubbles: the uniaxial straining flow. We show that most of the dynamics ca
 n be reproduced by a 1D non linear oscillator on the oblate-prolate deform
 ation mode. We then extend these results to a turbulent flow\, by running 
 direct numerical simulations of a single bubble in an homogeneous and isot
 ropic turbulent flow. Similarly\, we show that a 1D model is sufficient to
  describe most of bubble deformations\, as well as predicting bubble lifet
 ime.\n\nBio:\nAliénor Rivière is a Ph.D. student at PMMH\, ESPCI in Fran
 ce\, where she studies the deformation and fragmentation dynamics of bubbl
 es in turbulent flows. She obtained a M.Sc. from Sorbonne Université\, as
  well as a M.Sc. from the École Normale Supérieure in Paris. Before that
 \, she completed her B.Sc. at the École Normale Supérieure in Paris. Her
  research lies at the intersection between interfacial dynamics and turbul
 ence\, with a strong interest in nonlinear physics. Her approach combines 
 numerical simulations of simplified configurations as well as direct numer
 ical simulations and theory\, to understand the mechanisms at play. She wa
 s awarded the 2023 Frenkiel Award for Fluid Mechanics.\n\n\n 
LOCATION:MED 1 1518 https://plan.epfl.ch/?room==MED%201%201518
STATUS:CONFIRMED
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