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, ∆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.

Faraday Waves in strongly interacting superfluids

“…Smits et al [8], in turn, identified that Faraday patterns in a BEC present the same behavior as a discrete space-time crystal [9], providing a new scenario for the research of nonequilibrium phase transitions and spontaneus symmetry breaking [10]. Moreover, these excitations have also been explored in superfluid liquid 4 He, where they are a precursor to the formation of classical (non-quantized) vortices [11].…”

“…Its study dates back to the 19th century when Michael Faraday first observed them on vertically shaken fluids [2]. Faraday waves are, in fact, a ubiquitous phenomenon in non-linear fluids and have been studied in a large variety of systems such as viscoelastic fluids [3], granular media [4], and even in living soft systems such as earth-worms [5]. Naturally, superfluids are not an exception.…”