Sediment motion induced by Faraday waves in a Hele-Shaw cell

Abstract

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 Δhc, a transition between a flat motionless granular layer and a second regime in which the granular layer undulates and oscillates periodically was observed. For the smallest value of dp (for which the Stokes number was Stâ‰1) the reduced acceleration Γ=a/g (g is the acceleration of gravity) is independent of Δhc, while for the larger ones, Γ depends linearly on Δhc. Finally, it is shown that at the onset of grain motion, the wave velocity Vw=hwf/2 (hw is the wave amplitude) depends linearly on Δhc and is independent of dp.