Influence of memory on trajectory in a harmonic potential
New reference website from Paris Couder & Fort Team
The Paris team led by Yves Couder & Emmanuel Fort has published online a wonderful reference website, with many new videos
emergence of statistical pattern in a 1D cavity
On this video you will see how a walking droplet in a small 1D cavity moves “randomly” if the memory of the system is high enough (ie if the forcing is strong enough, but still below the Faraday Thresold)
And how a statistical pattern emerges with time
Rainbow colored dotwave
Dotwave picture on Phys.org
Russian Physicians from Moscow Institute of Physics and Technology have chosen a dotwave.org picture to illustrate an article published on phys.org concerning their latest paper,
Des physiciens russes de l’institut de physique et de technologie de Moscou ont choisi une de mes photos pour illustrer un rĂ©sumĂ© d’un de leur papier sur les ondes de Faraday publiĂ© sur phys.org
Physics Today : letters to the editor
Read MoreEmergent quantization in a square box
Goal of the experiment :
A walking droplet is placed in a square box, at the onset of Faraday thresold.
The trajectory of the droplet is mapped.
In the long time limit, does a self-interference pattern appear ? what’s its shape ? How does it relate to the square cavity surface wave eigen-modes ?
cf. experiment by Bush et al. : in a circular corral
http://dotwave.org/wavelike-statistics-from-pilot-wave-dynamics-in-a-circular-corral/
In short, we try to reproduce the experiment of Bush et al, but in a square box.
First result :
A walking droplet in a square cavity shows random motion, but with time, its trajectory is building a statistic reminiscent of the resonant mode of the cavity.
This can be seen by the naked eye in this movie excerpt :
This is then confirmed with optical tracking measurment of the trajectory :
The position distribution (~probability density) is then computed :
PDF Version of this résumé :
Emergent quantization of trajectories in a square box
Mini Colloque RNL 2016 : DualitĂ© onde-corpuscule Ă lâĂ©chelle macroscopique
I was lucky enough to attend this mini-colloque !!
“Si la dualitĂ© onde-corpuscule est une des bases de lâinterprĂ©tation de la mĂ©canique quantique, elle peut aussi se manifester Ă lâĂ©chelle macroscopique. Durant ce mini-colloque seront prĂ©sentĂ©es les propriĂ©tĂ©s observĂ©es dans des systĂšmes macroscopiques, ainsi que quelques-unes de leurs pendants aux Ă©chelles microscopiques. Un des objectifs est dâidentifier les analogies et les diffĂ©rences entre ces deux types de systĂšmes.”
http://nonlineaire.univ-lille1.fr/SNL/media/2016/programme/ProgrammeMiniColloque2016.pdf
DotWave Keynote at XLIM Lab in Limoges
“Fingers and Holes in a Shaken Cornstrach Solution” sur YouTube
Quasi particles in the middle of faraday waves :
Fingers and Holes in a Shaken Cornstrach Solution : http://youtu.be/DrcShENMaoI
Birth of a dotwave (Un rebond peut en cacher un autre)
Read MoreVideo Lesson – 07/06/2013 – Hydrodynamic Modelling of Pilot-Wave and boucing droplet coupling in a Faraday Problem
“Recent experiments by two groups, Yves Couder (Paris) and JohnÂ
Bush (MIT) have shown experimentally that droplets will bounce on theÂ
surface of a vertically vibrated bath (instead of coalescing with it),Â
generating a Faraday-type wavefield at every bounce. From this state, aÂ
pitchfork symmetry breaking bifurcation leads to a “walking” state wherebyÂ
the bouncing droplet is “guided” by the self-generated wavefield – theÂ
droplet’s pilot wave. Once this state is achieved a large array ofÂ
interesting dynamics ensues with surprising analogies to quantumÂ
mechanical behaviour. We will present a coupled particle-fluid model thatÂ
can can be used simulate the dynamics of this problem. This is joint workÂ
with John Bush, Andre Nachbin (IMPA) and Carlos Galeano (IMPA)”
Bouncing droplet project — single-slit diffraction
A video from TAFLAB at Berkeley University
SPH Simulation of a walking droplet
A new kind of simulation using Smoothed particle hydrodynamics by Diego Molteni, Università degli studi di Palermo, Dipartimento di Fisica e Chimic
Vortex-mediated bouncing drops on an oscillating liquid
Chu, H. Y., & Fei, H. T. (2014). Vortex-mediated bouncing drops on an oscillating liquid. Physical Review E, 89(6), 063011
 http://journals.aps.org/pre/abstract/10.1103/PhysRevE.89.063011 (Subsrciption required)
Stunning Vizualisization of undersurface flows
Abstract :
We have investigated the behavior of bouncing drops on a liquid surface by using particle image velocimetry analysis. A drop on an oscillating liquid surface is observed to not coalesce with the liquid and to travel along the surface if the oscillation is strong enough. A streaming vortex pair, induced by the alternatively distorted liquid surface, shows up below a bouncing drop. The time-averaged flow fields of the vortices are measured. In our quasi-one-dimensional setup, there are three stable distances for the drops, which can be characterized by the Faraday wavelength. The interactions of the vortex-mediated bouncing drops are deduced from the streamlines in the liquid bulk. We further show that a three-dimensional vortex ring is induced by a bouncing drop in a square cell.
Dotwave @ 240 frame per Seconds with modified GoPro
This is how precise my temporal resolution can be with my modified goPro and (at last) a good lens : 240 fps ( @848Ă480 )
Forcing freq is 60 Hz, so Faraday Freq is 30Hz, so for the usual walking mode we have 8 frame during the period of the vertical dynamic. Hence we can observe the dynamic without any strobe effect.
Question: What is the (m, n) mode of the first droplet shown in the movie ?
Uneven Faraday Instability
Dotwave Sonification
Even if the ear cannot detect any transition on this one, it might give somebody … ideas ?
( Sound is the derivative of the sum of all field values at the center )