SCIENCE NON LINÉAIRE

Soumis le 17 Mar 2015 par Boris Filoux

Mot(s)-clé(s) : marcheurs, gouttes rebondissantes, onde cohérente

Chaîne de huit gouttes marcheuses se déplaçant au sein d'une cavité annulaire. Toutes les gouttes sont placées à la même distance, et suivent une trajectoire circulaire. Les marcheurs sont en opposition de phase, comme l'indique l'ombre au dessous des gouttes. A chaque rebond, les gouttes émettent des ondes qui propulsent la chaîne. L’onde, dans ce cas précis, est cohérente et propulse la chaîne à une vitesse nettement supérieure à celle prédite dans le cas d’une goutte seule. @ http://grasp-lab.org

Soumis le 16 Mar 2015 par Wahb Ettoumi

This image shows the simulation of a high power laser cross section, which has been processed so as to feature only islands of light exceeding a certain amount of power, which were in turn colored according to their relative size. This clustering of light into zones of high (colors) and low (white) intensity results from a linear instability in the non-linear Schrödinger Equation, and is found to exhibit statistical properties reminiscent of those of percolation problems.

Soumis le 13 Mar 2015 par Giuseppe Pucci

Mot(s)-clé(s) : Partial coalescence, bubble, soap film, surface tension

In this image we see four steps of the partial coalescence of a soap bubble on a soap film. The bubble is gently deposited on the film. The film at the point of merger ruptures, so the high pressure air inside the bubble is evacuated. One might expect complete coalescence, that the surface would simply return to a planar configuration in order to minimize the overall surface area. Instead, capillary waves sweep up the bubble and initiate pinch-off, resulting in a smaller daughter bubble. The daughter bubble has approximately half the radius of its progenitor. The process repeats itself up ...