Algorithms in a Robust Hybrid CFD-DEM Solver for Particle-Laden Flows
Heng Xiao 1*, Jin Sun 21 Institute of Fluid Dynamics, ETH Zurich, 8092 Zurich, Switzerland.
2 Institute for Infrastructure and Environment, The University of Edinburgh, Edinburgh EH9 3JL, United Kingdom.
Received 26 May 2009; Accepted (in revised version) 23 February 2010
Available online 27 August 2010
A robust and efficient solver coupling computational fluid dynamics (CFD) with discrete element method (DEM) is developed to simulate particle-laden flows in various physical settings. An interpolation algorithm suitable for unstructured meshes is proposed to translate between mesh-based Eulerian fields and particle-based Lagrangian quantities. The interpolation scheme reduces the mesh-dependence of the averaging and interpolation procedures. In addition, the fluid-particle interaction terms are treated semi-implicitly in this algorithm to improve stability and to maintain accuracy. Finally, it is demonstrated that sub-stepping is desirable for fluid-particle systems with small Stokes numbers. A momentum-conserving sub-stepping technique is introduced into the fluid-particle coupling procedure, so that problems with a wide range of time scales can be solved without resorting to excessively small time steps in the CFD solver. Several numerical examples are presented to demonstrate the capabilities of the solver and the merits of the algorithm.PACS: 47.55.Kf, 47.57.Gc
Key words: Fluid-particle interaction, particle-laden flow, discrete element method, computational fluid dynamics, hybrid model.
Email: firstname.lastname@example.org (H. Xiao), email@example.com (J. Sun)