Numerical approach to frictional fingers

Area of Science:

• Fluid dynamics
• Materials science
• Physics of granular materials

Background:

• Confined two-phase flow systems exhibit complex behaviors when air displaces dense suspensions.
• Bead accumulation at the interface can lead to the formation of "frictional fingers".

Purpose of the Study:

• To present a simplified model for frictional finger dynamics.
• To introduce a novel numerical strategy for simulating these structures.
• To theoretically predict and experimentally validate the characteristic width of frictional fingers.

Main Methods:

• Development of a simplified model based on the yield stress criterion of the interface.
• Implementation of a new discretization scheme for enhanced simulation capabilities.
• Theoretical prediction of frictional finger width using the yield stress criterion.
• Comparison of theoretical predictions with experimental results.

Main Results:

• The simplified model and numerical strategy successfully simulate frictional finger behavior.
• The new discretization scheme allows for simulating a wider range of structures.
• Theoretical predictions for frictional finger width show good agreement with experimental data.
• An unknown parameter in the yield stress criterion was estimated.

Conclusions:

• The developed model and simulation strategy are validated by experimental results.
• The study provides a robust framework for understanding and simulating frictional finger formation.
• The findings contribute to the understanding of interface dynamics in dense suspensions.