A molecular collision operator of adjustable direction for the discrete velocity direction model

Zhenyu Zhang, Cheng Peng and Jianzhong Xu

Physica A: Statistical Mechanics and its Applications, 2017, vol. 483, issue C, 25-35

Abstract: The discrete velocity direction model is an approximate method to the Boltzmann equation. A developed molecular collision operator for the model is presented in this paper. Under the new operator, the discrete directions of molecules are adjustable, namely, both the number and the angles of discrete directions can be changed as needed in the discrete velocity direction model. At the same time, the governing equations will keep unchanged when the number of discrete directions changes. In fact, with the continuous molecular speed, the discrete velocity direction model has been able to employ any discrete velocities in numerical calculations. The discrete velocity direction model under the new collision operator was applied into some benchmark flows in micro scales in this paper, and the influence of the number of discrete velocities on the computational accuracy was analyzed. The numerical results show that the accuracy of the discrete velocity direction model can be improved significantly by employing more discrete directions, especially for the gas flows at large Knudsen number. With appropriate discrete velocities, this model has been able to give accurate numerical results in all flow regimes. In addition, it is proved that the discrete velocity direction model under the new collision operator satisfies a global H theorem unconditionally, which means that the new operator further improves the intrinsic stability of the discrete velocity direction model.

Keywords: Collision operator; Discrete velocity direction model; Micro gas flows; Transition regime; Low-speed (search for similar items in EconPapers)
Date: 2017
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0378437117303874
Full text for ScienceDirect subscribers only. Journal offers the option of making the article available online on Science direct for a fee of $3,000

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:phsmap:v:483:y:2017:i:c:p:25-35

DOI: 10.1016/j.physa.2017.04.077

Access Statistics for this article

Physica A: Statistical Mechanics and its Applications is currently edited by K. A. Dawson, J. O. Indekeu, H.E. Stanley and C. Tsallis

More articles in Physica A: Statistical Mechanics and its Applications from Elsevier
Bibliographic data for series maintained by Catherine Liu ().