Erosion dynamics of a wet granular medium

Area of Science:

• Physics of granular materials
• Fluid dynamics
• Material science

Background:

• Liquids can induce cohesion in granular media, leading to solid-like behavior.
• Understanding erosion in wet granular systems is crucial for various industrial and natural processes.

Purpose of the Study:

• To investigate the erosion of a wet granular aggregate under dry grain flow.
• To quantify the influence of liquid properties (surface tension, viscosity) on erosion rate.
• To develop a predictive model for wet granular erosion.

Main Methods:

• Experimental setup involving a rotating drum with a fixed wet granular aggregate and flowing dry grains.
• Systematic variation of liquid content and properties.
• Analysis of aggregate diameter change over time.
• Development and validation of a force-fluctuation-based erosion model.

Main Results:

• Aggregate diameter decreases linearly with time at low liquid content.
• Erosion rate exhibits an exponential dependence on surface tension and a power of -1 dependence on viscosity.
• The proposed model accurately predicts the observed erosion dynamics.

Conclusions:

• Liquid properties significantly govern the erosion of wet granular aggregates.
• Capillary forces act as an erosion threshold, while viscosity dictates the erosion timescale.
• The study provides a robust model for predicting erosion in such systems.