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Updated: Jun 19, 2026
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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Mean steady granular force on a wall overflowed by free-surface gravity-driven dense flows.
Thierry Faug1, Rémi Beguin, Benoit Chanut
1Cemagref, ETGR, 38402 St. Martin d'Hères, France. thierry.faug@cemagref.fr
Summary
This study investigates granular flows impacting obstacles, revealing that a stagnant zone upstream significantly increases force at low flow rates. A simple hydrodynamic model accurately predicts these forces, showcasing its utility for granular material dynamics.
Area of Science:
- Physics
- Geophysics
- Fluid Dynamics
Background:
- Granular materials exhibit complex behaviors in gravity-driven flows.
- Understanding forces on obstacles in such flows is crucial for engineering and geophysical applications.
- Previous models often simplify granular dynamics, limiting predictive power.
Purpose of the Study:
- To investigate the relationship between the mean force on an obstacle and the inertial number of incoming granular flows.
- To develop and validate a simple hydrodynamic model for predicting forces in granular flows over obstacles.
- To analyze the formation and impact of stagnant zones on force exertion.
Main Methods:
- Two-dimensional discrete element simulations of cohesionless granular materials were performed.
- A linear damped spring law and Coulomb failure criterion were used for particle interactions.
- The study focused on analyzing mean steady forces against the macroscopic inertial number.
Main Results:
- High-frequency force fluctuations were observed in the simulations.
- A triangular stagnant zone upstream of the obstacle was identified.
- This stagnant zone significantly increased the mean force on the obstacle at low inertial numbers.
Conclusions:
- A simple depth-averaged hydrodynamic model based on momentum conservation effectively predicts numerical data.
- The model quantifies contributions to the mean force on the obstacle.
- Hydrodynamic approaches can accurately describe the macroscopic kinematics and forces of granular assemblies.
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