The interaction between the oscillatory boundary-layer flow induced by Faraday waves and a sedimentary granular layer was studied in a Hele-Shaw cell vertically vibrated. The experimental parameters were the vibration frequency f and acceleration a, and the particle diameter dp. At a critical value for the depth of the supernatant fluid layer, ∆hc, it was observed a transition between a flat motionless granular layer and a second regime in which the granular layer undulates and oscillates periodically. For the smallest value of dp (for which the Stokes number was St << 1) the reduced acceleration Γ = a/g (g is the acceleration of gravity) is independent on ∆hc, while for the larger ones, Γ depends linearly on ∆hc. Finally, it is shown that at the onset of grains motion, the wave velocity Vw = hwf /2 (hw is the wave amplitude) depends linearly on ∆hc and is independent of dp.

No abstract

No abstract