Improvement of a Resolved Open Source Fluid-Particle Interaction Method
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ECCOMAS 2012, September 10-14, Vienna, Austria
In this paper we present a resolved method for the representation of immersed bodies within a fluid phase. A basic version of this solver has already been published by the authors (e.g. [Hager, Kloss, Pirker, Goniva, (2011). Efficient realization of a resolved CFD-DEM method within an Open Source framework, Proc. OSCIC 2011, Paris]). The method is realized within the Open Source framework CFDEM (www.cfdem.com), a coupling software that provides a link between the computational fluid dynamics (CFD) code OpenFOAM® and the discrete element method (DEM) LIGGGHTS.
Within the fluid phase the immersed bodies are described by a void fraction, which is set in the solid-covered cells. This marker function is used as a criterion for the incorporation of the velocity information stemming from the DEM solver, resulting in a single velocity, and, further on, pressure field. The DEM code is provided with the drag force the fluid puts onto the bodies. It is added to the force terms evolving during the DEM calculation.
Both CFD and DEM solver run side by side, exchanging data at predefined points in time. As the calculations might require different time step widths, the number of time steps between the interchange of data can be chosen flexibly.
The recent parallelization of the CFD solver permits the fully parallel and thus very efficient computation of the investigated problems.
Asides from a theoretical part this paper comprises a number of validation and application examples, showing correctness and feasibility of the proposed method.