BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:MechE Colloquium: Why does an inverted-flag flap in a uniform stea
 dy flow?
DTSTART:20230530T120000
DTEND:20230530T130000
DTSTAMP:20260414T224502Z
UID:5c64440bf43516bb3bd08daac11949493bc41e82d28797fecb753784
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. John Sader\, Graduate Aerospace Laboratories and Depart
 ment of Applied Physics\, California Institute of Technology (Caltech)\nA
 bstract: The dynamics of a cantilevered elastic sheet\, with a uniform ste
 ady flow impinging on its clamped end\, have been studied widely and provi
 de insight into the stability of flags and biological phenomena. Measureme
 nts show that reversing the sheet's orientation\, with the flow impinging 
 on its free-edge—producing an “inverted flag”—dramatically alters 
 its dynamics. In contrast to the conventional flag\, which exhibits (small
 -amplitude) flutter above a critical flow speed\, the inverted-flag displa
 ys large-amplitude flapping over a finite band of flow speeds. In this tal
 k\, I will give an overview of our work on this canonical problem that use
 s a combination of mathematical theory\, scaling analysis\, direct numeric
 al simulations\, and measurement. Flapping is found to be a vortex-induced
  vibration and is periodic predominantly\, with a transition to chaos as f
 low speed increases. The effect of sheet motion on vortex formation will a
 lso be explored. This work was motivated by energy generation using wind t
 urbines. It also has broader implications to leaf motion\, and other biolo
 gical processes such as the dynamics of hairs\, because they also can pres
 ent an inverted-flag configuration.\n\nBiography: John Sader is an applied
  mathematician with interests across a broad range of areas\, including fl
 uid mechanics\, colloid science\, plasmonics\, mass spectrometry and atomi
 c force microscopy. John collaborates broadly with experimentalists and is
  perhaps best known for developing experimental methods in atomic force mi
 croscopy. Having completed his PhD in electrical engineering from the Univ
 ersity of New South Wales\, John joined the University of Melbourne in 199
 2 as a research fellow\, progressing to Professor of Applied Mathematics\
 , until moving to the California Institute of Technology as Research Profe
 ssor of Aerospace and Applied Physics in 2022. He has published over 180 i
 nternational refereed journal papers with more than 240 collaborators fro
 m 66 institutions worldwide. John is an elected fellow of the Australian A
 cademy of Science\, the Australasian Fluid Mechanics Society\, and the Aus
 tralian Mathematical Society.
LOCATION:MED 0 1418 https://plan.epfl.ch/?room==MED%200%201418 https://epf
 l.zoom.us/j/64230566011
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR