Toward Accurate Models of Wet Granular Media in Nature
Abstract
Major Goals: This short project was aimed at discrete and continuum simulation methods for wet granular materials. The project explored modeling of slightly wet grains (i.e. the pendular regime) and fully saturated grains. These two areas were treated as two separate problems. On the partially wet side, the first goal was to write a novel and robust discrete element method that captures fluid bridging, fluid transfer during contact breaking, and time-dependence of bridge formation, simultaneous with frictional contact modeling of grain-on-grain interaction. Once achieved, the discrete method can be used like an experiment to identify homogenized continuum relations. On the fully saturated side, our aim was to develop an effective LBM-DEM method that could be used to provide inputs to a poro-plastic type continuum model. The goal was to cast the continuum model within a meshless numerical framework that permits huge deformations. Transitioning a finite-element poro-plastic approach to a meshless one would utilize the consultation of Prof David Henann at Brown, a finite-element expert. Geoscientist Dr. Colin Stark at NYU would help with the selection of natural particle-scale input parameters. Accomplishments: Many of the goals proposed were accomplished, though some of them materialized after the close date of the short grant. On the discrete side, were able to write and implement a custom method that tracks the fluid layer thickness on each grain as a separate degree of freedom. During contact, the layer thicknesses of the contact pairs evolve dynamically as fluid is (viscously) driven into the bridge. As the bridge is forming, the strength of the bridge itself is evolving with it as a function of bridge volume. The current bridge volume is appended to the discrete system as a new "contact" variable.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 14, 2016
- Accession Number
- AD1077551
Entities
People
- Kenneth N Kamrin
Organizations
- Massachusetts Institute of Technology