Friday, March 1, 2013
Contact of Particles in Fluids
Peter Wriggers, Professor, Institute of Continuum Mechanics, Leibniz University of Hannover
This presentation is related to contact and coupling of particles and fluids, and thus is concerned with particle‐fluid flow systems. These are of great practical importance in the production processes of chemical and food industries as well as in geological engineering problems related to fluvial erosion, fluidized beds and sedimentation. Such problems generally require an accurate characterization and a highly resolved model of the fluid‐particle flow at multiple temporal and spatial scales. In particular, in order to account for the microscale particle‐fluid and particle‐particle interactions within the coupled two-phase flow system, the numerical resolution should be of the order of a representative particle dimension. For these purposes, an efficient fictitious boundary method is applied to the simulation of three‐dimensional large‐scale particle‐fluid flows. Within this approach, the Newton‐Euler equations of the particle dynamics are solved with the Discrete Element Method, while the Navier‐Stokes equations describing the fluid flow are solved via a multigrid Finite Element Method within an Eulerian setting. Coupling of the particles to the flow is realized by applying additional constraints to the Navier‐Stokes equations at the interfaces of the particle and fluid domains. The Eulerian setting eliminates the need for remeshing of the analysis domain in each time- step, a process that can be prohibitively expensive for large particle numbers. Several examples are used to verify and validate the derived model and numerical method.