Volume 87, Number 5, September 2009
Article Number 54004
Number of page(s) 5
Section Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics
Published online 22 September 2009
EPL, 87 (2009) 54004
DOI: 10.1209/0295-5075/87/54004

Oscillatory instability of interacting grains in a turbulent flow

B. Gallet and F. Pétrélis

Laboratoire de Physique Statistique, Ecole Normale Supérieure, CNRS UMR 8550 - 24 rue Lhomond, 75005 Paris, France, EU

received 22 April 2009; accepted in final form 24 August 2009; published September 2009
published online 22 September 2009

We present an instability occuring in a turbulent flow containing grains that interact via a dipole-dipole force. Above a critical intensity of the interaction, the local density of grains displays a noisy oscillation. This instability takes place in a spatially and temporally fluctuating medium. We identify the control parameter of the instability and study the statistical properties of the local density. In spite of the turbulent fluctuations, measurements performed at different positions show that a spatially coherent mode is generated.

45.70.Mg - Granular flow: mixing, segregation and stratification.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.
05.45.-a - Nonlinear dynamics and chaos.

© EPLA 2009