Restricted Collision List method for faster Direct Simulation Monte-Carlo (DSMC) collisions

Macrossan, Michael N. (2016) Restricted Collision List method for faster Direct Simulation Monte-Carlo (DSMC) collisions. Journal of Computational Physics, 319 1-8. doi:10.1016/

Author Macrossan, Michael N.
Title Restricted Collision List method for faster Direct Simulation Monte-Carlo (DSMC) collisions
Journal name Journal of Computational Physics   Check publisher's open access policy
ISSN 1090-2716
Publication date 2016-08-15
Year available 2016
Sub-type Article (original research)
DOI 10.1016/
Open Access Status Not Open Access
Volume 319
Start page 1
End page 8
Total pages 8
Place of publication Maryland Heights, MO United States
Publisher Academic Press
Collection year 2017
Language eng
Abstract The ‘Restricted Collision List’ (RCL) method for speeding up the calculation of DSMC Variable Soft Sphere collisions, with Borgnakke–Larsen (BL) energy exchange, is presented. The method cuts down considerably on the number of random collision parameters which must be calculated (deflection and azimuthal angles, and the BL energy exchange factors). A relatively short list of these parameters is generated and the parameters required in any cell are selected from this list. The list is regenerated at intervals approximately equal to the smallest mean collision time in the flow, and the chance of any particle re-using the same collision parameters in two successive collisions is negligible. The results using this method are indistinguishable from those obtained with standard DSMC. The CPU time saving depends on how much of a DSMC calculation is devoted to collisions and how much is devoted to other tasks, such as moving particles and calculating particle interactions with flow boundaries. For 1-dimensional calculations of flow in a tube, the new method saves 20% of the CPU time per collision for VSS scattering with no energy exchange. With RCL applied to rotational energy exchange, the CPU saving can be greater; for small values of the rotational collision number, for which most collisions involve some rotational energy exchange, the CPU may be reduced by 50% or more.
Keyword DSMC collisions
BL energy exchange
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mechanical & Mining Engineering Publications
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