I cannot stop playing with those droplets because when I start a session, I don't know what will come out !
This time, I set up a circular corral, carefully tuned just below the faraday thresold. I estimated a relaxation time of 30 secs after perturbation. Which means, at my usual 30 Hz droplet vertical period, a memory parameter of around 900 !
I started with a planar free surface and after several minutes I got a total ...... FREEZE !
But then (not shown on the vid), I destroyed the droplet and let the surface relax more than 15 minutes ... waves were still here, a bit diminished. Which means, I was in fact above Faraday thresold at the beginning...yet there was no waves ???
Transition to Faraday waves if mainly described as supercritical but sometimes I do wonder ... !
NB : My device for generating waves is not pro, and not controlled, there might have been a shift in the forcing value in the middle...A bath of silicon oil is vibrated and oil droplets are deposited on the surface. Thanks to the vibrations, the droplets do not coalesce, but bounce on the surface.
For specific values of amplitude and frequencies, the droplet start to move forward by itself : while bouncing, it create waves with which it interacts.
This object has been called a walker, or a dotwave, and exhibits properties reminiscent of an elementary particle, because it is at the same time a particle (the droplet) and a wave (The local standing wave pattern created by the droplet)