Faraday instability on a network

Faraday waves are generated at the air/liquid interface inside an array of square cells. As the free surface inside each cell is destabiliz-ing due to the oscillations, the shape of the free surface is drastically changing. Depending on the value of the frequency f of oscillations, different patterns are observed inside each cell. For well defined f values, neighboring cells are observed to interact and a general orga-nization is noticed. In such a situation, initially disordered structures lead to a general pattern covering the entire liquid pool and a spatial order appears all over the cell array. This abstract is related to a fluid dynamics video for the gallery of fluid motion 2009. Under periodic oscillations, an air/liquid interface may become unstable to surface waves. Theses waves are known as Faraday waves, after the pioneer work of Faraday [1]. As a parametric instability, different kind of wave patterns may appear, depending on the excitation parameters [2, 3]. It has also been noticed that the pinning of the contact line at the wall/liquid interface plays a role in the dynamics of these waves [4]. In the present experiments, a liquid pool is divided into separated square cells by mean of a plexiglass grid. The walls separating the cells are 2.5 cm in height and have a width of 1 mm. These cells are partially filled with water or 10 cSt silicon oil. The vertical oscillations are characterized by a frequency f ranging from 10 Hz to 30 Hz and an amplitude of typically 1 mm. With the help of a high speed video camera, the emergence of Faraday waves is investigated. Beside individual behaviors the different cells, collective effects have been observed. In the linked videos, two collective modes are 1 a