Instability of the origami of a ferrofluid drop in a magnetic field

Timothée Jamin (1) , Charlotte Py (1) , Eric Falcon (1)

1 MSC - Matière et Systèmes Complexes

Capillary origami is the wrapping of an usual fluid drop by a planar elastic membrane due to the interplay between capillary and elastic forces. Here, we use a drop of magnetic fluid whose shape is known to strongly depend on an applied magnetic field. We study the quasi-static and dynamical behaviors of such a magnetic capillary origami. We report the observation of an overturning instability that the origami undergoes at a critical magnetic field. This instability is triggered by an interplay between magnetic and gravitational energies in agreement with the theory presented here. Additional effects of elasticity and capillarity on this instability are also discussed.

Mots clés: magnetic fluid; ferrofluid; origami; capillary; drop; elastic; elastocapillary phenomenon; liquid-solide interfaces; instability; tatic buckling; overturning instability; dynamical studies

Domaines: Dynamique des Fluides [physics.flu-dyn]; Mécanique des fluides [physics.class-ph]; Mécanique des solides [physics.class-ph]; Mécanique des solides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Timothée Jamin, Charlotte Py, Eric Falcon. Instability of the origami of a ferrofluid drop in a magnetic field. Physical Review Letters, 2011, 107 (204503), pp.2011. ⟨10.1103/PhysRevLett.107.204503⟩. ⟨hal-00635963⟩