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

Area of Science:

• Fluid dynamics
• Granular physics
• Nonlinear dynamics

Background:

• Faraday waves generate oscillatory boundary layers.
• Sedimentary granular layers respond to fluid motion.
• Vertical vibration influences granular system behavior.

Purpose of the Study:

• Investigate the interaction between Faraday wave-induced flow and granular layers.
• Determine critical conditions for transitions in granular layer dynamics.
• Analyze the influence of vibration parameters and particle size on granular behavior.

Main Methods:

• Experiments conducted in a vertically vibrated Hele-Shaw cell.
• System parameters: vibration frequency (f), acceleration (a), particle diameter (dₚ).
• Observation of transitions based on supernatant fluid layer depth (Δh).

Main Results:

• A critical fluid depth (Δh<0xE1><0xB5><0xA_>) induces a transition from a flat to an oscillating granular layer.
• Reduced acceleration (Γ) is independent of Δh<0xE1><0xB5><0xA_> for small particles (Stokes number St ≪ 1).
• Γ depends linearly on Δh<0xE1><0xB5><0xA_> for larger particles.
• Wave velocity (V<0xE1><0xB5><0xA_>) at grain motion onset is linear with Δh<0xE1><0xB5><0xA_> and independent of dₚ.

Conclusions:

• The depth of the overlying fluid is a key parameter controlling granular layer response to vibration.
• Particle size influences the critical acceleration required to initiate granular motion.
• Wave velocity dynamics at the onset of motion are primarily governed by fluid layer depth.