Research
Since coming to Berkeley, I have been extending my previous work on flow in dense granular materials, and currently have several research collaborations underway with different groups to probe the basic science of flowing granular and amorphous materials. I have also been learning more about continuum numerical techniques, including level set methods, fast marching methods, and multigrid methods, which I am hoping to apply to simulations of plastic injection molding in the near future.
For more information, see the short articles on my granular materials research, and also the pages highlighting some preliminary results and movies from my current collaborations. Further details can be found in my publications.
Current projects
- I'm beginning to work on a hybrid continuum–discrete model of granular flow with Jon Wilkening, combining local particle dynamics with a continuum model of flow and stress.
- I've been working with Jon Wilkening and Jamie Sethian on continuum simulations of plastic injection molding. As part of this, I've written an odd/even multigrid method that can solve elliptic PDEs on grids of arbitrary size.
- I've recently submitted a paper with Martin Bazant and Ken Kamrin. By analyzing several different granular flows at a local length scale, we were able to verify and disprove a number of continuum hypotheses about granular materials at a local level.
- I have been collaborating with Gary Grest on examining the rheology of dense granular materials in very large scale simulations of flow in conical hoppers. We have been comparing against some of the classical solutions for hopper flow, and preliminary results indicate that some of the predictions of plasticity theory do not hold.
- I an working with Ashish Orpe and Arshad Kudrolli at Clark University on a quantitative comparison of three dimensional DEM simulations, to experimental results of flowing glass beads in an index-matched fluid.
- I have written an open source software library called Voro++ for carrying out 3D cell-based Voronoi tessellations.
- I have been continuing my collaboration with Jim Langer, Frederic Gibou, and Lisa Manning at the Department of Physics at UC Santa Barbara. Most recently, we have been looking at simulations of an expanding hole in an infinite medium to examine the stability of the STZ theory.