Féderation de recherche Fabri de Peiresc

Grain dynamics on a vibrated membrane

Orateur : Anaïs Abramian / post-doctorante à l’institut Jean le Rond d’Alemberd

Abstract : When sand is sprinkled on a vibrated membrane, grains move until they eventually settle down in the nodes of vibration. During this phenomenon, grains behave as passive particles forming the so-called "Chladni patterns" that provide an easy visualization of the membrane’s modes. These patterns have significantly contributed to the development of vibration science and are still useful to design or tune a musical instrument. In some cases, for example in a liquid, microparticles can form inverse Chladni patterns by migrating in the antinodes of the vibrated membrane. The mechanisms of this phenomenon, and more generally of the transport of grains on a vibrated membrane, are still elusive.

Here, we propose to consider grains as random walkers, whose diffusivity depends on the membrane amplitude. This simple approach allows us to recover the dynamics of the system when grains are sufficiently light and do not interact with the membrane’s motion. If the grains become larger and heavier, they locally influence the vibration of the membrane. We are currently investigating this coupling with a 1D-experiment that consists of a bead standing on a vibrated ribbon, which reveals a rich phenomenology. In this talk, I will focus on how a bead can stabilize on such an elastic membrane.

Date et lieu : le vendredi 3 décembre à 11h ; amphi IRPHE