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SUMMARY:Changing size to swim: From added-mass powered escape maneuvers to
  resonance-exploiting robots. - Dr Gabriel Weymouth
DTSTART:20191115T130000Z
DTEND:20191115T140000Z
UID:TALK132379@talks.cam.ac.uk
CONTACT:Connor O'Pray
DESCRIPTION:Cephalopods and jellyfish use large-scale structural deformati
 on to propel themselves underwater\, changing their internal volume by 20-
 50%. This seminar will present recent findings on the internal and externa
 l flow dynamics resulting from shapes that change their internal volume an
 d how these findings may be exploited to improve the maneuvering and propu
 lsive efficiency of underwater vehicles and robotic. In the external flow\
 , rapid volume change results in the recovery of large added-mass propulsi
 ve forces and the control of boundary layer separation. A shrinking parame
 ter governs the ratio of energy recovered\, and sufficiently rapid shrinki
 ng was used to power a simple prototype vehicle through a fast-start maneu
 vers at record breaking acceleration. In the internal flow\, the large add
 ed-mass variation over a volume-pulsation cycle leads to a net thrust with
  similar magnitude to the net jet momentum. The large internal added-mass 
 also dominates the inertia of the freely swimming system\, which was explo
 ited to in a flexible robotic system which resonates to increase it's spee
 d and propulsive efficiency.
LOCATION:LR5\, Baker Building\, CUED.
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