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SUMMARY:MEchanics GAthering -MEGA- Seminar: Hysteresis and suspensions
DTSTART:20191205T161500
DTEND:20191205T173000
DTSTAMP:20261005T005351Z
UID:9b920585d99c5a8581a14c8fc49b36a6707b39ea786ad9bb3dc99f6b
CATEGORIES:Conferences - Seminars
DESCRIPTION:Hugo Perrin\, Marseille University/EPFL\nHysteresis is a major
  feature of the solid-liquid transition in granular materials. This proper
 ty\, by allowing metastable states\, can potentially yield catastrophic ph
 enomena such as landslides. The origin of hysteresis in granular flows is 
 still debated. However\, most mechanisms put forward so far rely on inerti
 a at the particle level.Here\, we study the avalanche dynamics of non-Brow
 nian suspensions in slowly rotating drums and reveal large hysteresis of t
 he avalanche angle even without inertia. By using microsilica particles wh
 ose interparticle friction can be turned off\, we show that microscopic fr
 iction\, conversely to inertia\, is key to triggering hysteresis. To under
 stand this link between friction and hysteresis\, we measured the suspensi
 on rheology close to the flow onset for frictional and frictionless suspen
 sions. We show that the flow rule for frictionless particles is monotonous
  with a power law of exponent 0.37\\pm0.05\, in close agreement with the p
 revious theoretical prediction\, 0.35. By contrast\, the flow rule for fri
 ctional particles suggests a velocity-weakening behavior. These findings s
 how that hysteresis can occur in particulate media without inertia\, and b
 y highlighting the role of microscopic friction\, it questions the intimat
 e nature of this phenomenon.
LOCATION:MED 2 2423 https://plan.epfl.ch/?room==MED%202%202423
STATUS:CONFIRMED
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