Non Linear Physics Group - Eric Falcon
Instabilities (papers by our group)
In granular layers:
We report free-surface instabilities in a deep bed of fine granular material of irregular shape under vertical vibrations. At low frequency of vibration, the conical heap due to convective flow becomes unstable above a critical amplitude of vibration and acquires an azimuthal dependence which makes the heap surface corrugated. At even higher amplitude, the heap is no longer stable and splits into small heaps on a hexagonal lattice. At high frequency, we observe standing waves (stripes) at the same frequency as the driving one. The main mechanism of these instabilities can be traced back to the presence of the surrounding gas, since they vanish under vacuum conditions.
Hexagon formation of a powder under vertical vibrations.
Right (left) photo vizualised with a direct (strob) light.
Heap Corrugation of
a powder under
The shape of the convective cell within the granular heap has been also studied (see paper)
We report an experimental study of the inhibition of the instability generated by a magnetic field applied perpendicularly to the surface of a magnetic fluid (the Rosensweig instability), by vertical vibrations of the fluid container. Our measurements are in quantitative agreement with a simple analytical model using the theory of Mathieu functions. Paper
An apparatus has been built to measure the shear response of a multicontact interface between flat-ended solid bodies, rough at the micron scale. The device makes use of inertia to apply a steady sinusoidal shear force to a slider without direct mechanical drive. Both elastic compliance and damping losses are deduced from the in-phase and out-of-phase components of the submicronic shear displacement. The resolution of the microslip detection is 1 nm. Apparatus design and operation are described, and the application and limitation of the method are illustrated by experimental results with a polymer glass. Paper
- In fluid:
11. F. Bonnefoy, A. Tikan, F. Copie, P. Suret, G. Ducrozet, G. Pradehusai, G. Michel, A. Cazaubiel, E. Falcon, G. El & S. Randoux 2020
Physical Review Fluids (2020) 5, 034802 (2020)
From modulation instability to focusing dam breaks in water waves
- 10. C. Laroche, J.-C. Bacri, M. Devaud, T. Jamin & E. Falcon 2019
Physical Review Letters 123, 094502 (2019)
- Observation of the resonance frequencies of a stable torus of fluid
- 9. E. Falcon, J.-C. Bacri & C. Laroche, 2017
- Physical Review Fluids 2, 102601(R) (2017) - Rapid Communication
- Dissipated power within a turbulent flow forced homogeneously by magnetic particlesIn ferrofluid:
- 8. T. Jamin, Y. Djama, J.-C. Bacri & E. Falcon 2016
Physical Review Fluids 1, 021901(R) (2016) - Rapid Communication
Tuning the resonant frequencies of a drop by a magnetic field
7. T. Jamin, C. Py & E. Falcon 2011
Instability of the origami of a ferrofluid drop in a magnetic field
Phys. Rev. Lett. 107, 204503 (2011)
- 6. F. Pétrélis, E. Falcon & S. Fauve 2000
- Parametric stabilization of the Rosensweig instability.European Physical Journal B, 15, 3 - 6 (2000)
In granular layers:
- 5. Falcon, E., Castaing, B. & Creyssels, M. 2005:
Propriétés électriques de la matière granulaire: Bruit et intermittence
- Bulletin de la Société Française de Physique, 149, 6 - 9 (2005) (in french)
- 4. Falcon, E., Castaing, B. & Laroche, C. 2004
- ''Turbulent'' electrical transport in Copper powders
Europhysics Letters 65, 186-192 (2004).
- 3. Kumar, K., Falcon, E., Bajaj, K. M. S., & Fauve, S. 1999
- Shape of convective cell in Faraday experiment with fine granular materials
Physica A , 270, 97-104 (1999).
- 2. Falcon, E., Kumar, K., Bajaj, K. M. S. & Bhattacharjee, J. K. 1999
- Heap corrugation and hexagon formation of powder under vertical vibrations.
Physical Review E, 59, 5, 5716-5720 (1999).
- 1. Baumberger,T. , Bureau, L., Busson, M., Falcon, E. & Perrin, B. 1998
- An inertial tribometer for measuring micro-slip dissipation at a solid-solid multicontact interface.
Review of Scientific Instruments 69 , 6, 2416-2420 (1998).