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SUMMARY:Capillary-Gravity Waves - Elie Raphael\, ESPCI\, Paris\, France
DTSTART:20080509T131500Z
DTEND:20080509T141500Z
UID:TALK11590@talks.cam.ac.uk
CONTACT:Dr Kalin Dragnevski
DESCRIPTION:It is generally believed that in order to generate waves\, a s
 mall object (like an insect) moving at the air-water surface\nmust exceed 
 the minimum capillary-gravity wave speed (about 23 centimeters per second)
 . We have shown recently that this result\nis only valid for a rectilinear
  uniform motion\, an assumption often overlooked in the literature. In the
  case of a steady circular motion\n(a situation of particular importance f
 or the study of whirligig beetles)\, we demonstrate that no such velocity 
 threshold\nexists and that even at small velocities a finite wave drag is 
 experienced by the object. This wave drag originates\nfrom the emission of
  a spiral-like wave pattern. It would be very interesting to know if whirl
 igig\nbeetles can take advantage of such spirals for echolocation purposes
 . 
LOCATION:IRC in Superconductivity Seminar Room\, Cavendish Laboratory
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