Collisions of small and heavy non-spherical particles settling in a turbulent environment are very important to various fields of physics and engineering. However, in contrast to spherical particles the collision probabilities are virtually unknown. In this study we focus on a very important condition for the numerical determination of collision probabilities: the collision detection. We discuss the need for efficient strategies to narrow down the number of possible collision pairs and compare three collision detection methods for ellipsoidal particles. We derive an analytical formula for the collision probability in the case of gravitational settling and validate the collision detection methods with this. Finally, we present statistics of the accuracy and efficiency of the methods. For the case of ellipsoidal particles in turbulence we find that the continuous collision detection with neglected rotation within a time step is the optimal trade-off between accuracy and efficiency.
- Fluids Engineering Division
On the Collision Detection for Ellipsoidal Particles in Turbulence
Siewert, C, Kunnen, RPJ, Meinke, M, & Schröder, W. "On the Collision Detection for Ellipsoidal Particles in Turbulence." Proceedings of the ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. Volume 1D, Symposia: Transport Phenomena in Mixing; Turbulent Flows; Urban Fluid Mechanics; Fluid Dynamic Behavior of Complex Particles; Analysis of Elementary Processes in Dispersed Multiphase Flows; Multiphase Flow With Heat/Mass Transfer in Process Technology; Fluid Mechanics of Aircraft and Rocket Emissions and Their Environmental Impacts; High Performance CFD Computation; Performance of Multiphase Flow Systems; Wind Energy; Uncertainty Quantification in Flow Measurements and Simulations. Chicago, Illinois, USA. August 3–7, 2014. V01DT30A005. ASME. https://doi.org/10.1115/FEDSM2014-21982
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