An association of particules and waves on a fluid interface
Seminar Room 1, Newton Institute
We will-first show in which conditions liquid drops can be kept bouncing indefinitely on the surface of a bath of the same fluid if this bath is oscillated vertically. With a fluid of small viscosity, this bouncing generates capillary waves. We thus obtain objects formed of the close association of a particle (the drop) with the wave it emits. Usually the drop is a simple" bouncer", motionless on the fluid surface. However, close to the Faraday instability threshold, a bifurcation is observed where the drop becomes what we call a "walker" moving at a constant velocity on the interface. A model describing the drop interaction with its own wave accounts for this bifurcation. When several bouncers or several walkers are present on the same interface they have non-local interactions due to the superposition of their waves. We will show that these interactions leed to the self organization of bouncers into bound states and crystalline clusters. With walkers the formation of orbiting pairs will be described.