Archimedes' principle in fluidized granular systems.

Area of Science:

• Physics
• Granular Mechanics
• Fluid Dynamics

Background:

• Understanding granular material behavior is crucial in various industrial processes.
• Fluidization of granular beds typically involves upward flow of gas or liquid.
• Alternative methods for granular bed fluidization, like mechanical vibrations, are less explored.

Purpose of the Study:

• To investigate the fluidization of a granular bed using high-frequency horizontal vibrations.
• To measure buoyancy forces and frictional drag on immersed objects in the vibrated granular bed.
• To validate Archimedes' principle and analyze the dependence of drag on vibration energy.

Main Methods:

• A granular bed in a rectangular container was fluidized via high-frequency sinusoidal horizontal vibrations applied to lateral walls.
• Buoyancy forces on light spheres were measured within the fluidized bed.
• Ascension velocities and rising times of intruders were recorded as functions of vibration energy and intruder density.

Main Results:

• The fluidized granular bed achieved a steady state without convection.
• Measured buoyancy forces on immersed spheres adhered to Archimedes' principle.
• Buoyancy forces diminished with reduced injected vibrational energy; frictional drag showed exponential dependence on vibration intensity, consistent with prior research.

Conclusions:

• High-frequency horizontal vibrations effectively fluidize granular beds without convection.
• Archimedes' principle is applicable in vibrated granular fluid systems.
• The study provides a method to evaluate frictional drag and confirms its relationship with vibration energy.