title: Mesoscale dynamic coupling of finite- and discrete-element methods for fluid-particle interactions.
abstract: A new method for two-way fluid-particle coupling on an unstructured mesoscopically coarse mesh is presented. In this approach, we combine a (higher order) finite-element method (FEM) on the moving mesh for the fluid with a soft sphere discrete-element method for the particles. The novel feature of the proposed scheme is that the FEM mesh is a dynamic Delaunay triangulation based on the positions of the moving particles. Thus, the mesh can be multi-purpose: it provides (i) a framework for the discretization of the Navier-Stokes equations, (ii) a simple tool for detecting contacts between moving particles, (iii) a basis for coarse-graining or upscaling, and (iv) coupling with other physical fields (temperature, electromagnetic, etc.). This approach is suitable for a wide range of dilute and dense particulate flows, because the mesh resolution adapts with particle density in a given region. Two-way momentum exchange is implemented using semi-empirical drag laws akin to other popular approaches; for example, the discrete particle method, where a finite-volume solver on a coarser, fixed grid is used. We validate the methodology with several basic test cases, including single- and double-particle settling with analytical and empirical expectations, and flow through ordered and random porous media, when compared against finely resolved FEM simulations of flow through fixed arrays of particles.
authors: Multi Scale Mechanics, MESA+ Institute for Nanotechnology, Faculty of Engineering Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
authors: S
authors: S
authors: Srivastava
authors: Multi Scale Mechanics, MESA+ Institute for Nanotechnology, Faculty of Engineering Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands kyazdchi@gmail.com.
authors: K
authors: K
authors: Yazdchi
authors: Multi Scale Mechanics, MESA+ Institute for Nanotechnology, Faculty of Engineering Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands s.luding@utwente.nl.
authors: S
authors: S
authors: Luding
keywords: Delaunay tessellation; discrete-element method two-way coupling; finite-element
  method; multi-phase flow; multi-scale methods; numerical analysis