Year: 2020
Author: Yaqun Yu, Yousheng Zhang, Baolin Tian, Zeyao Mo
Communications in Computational Physics, Vol. 27 (2020), Iss. 2 : pp. 503–512
Abstract
A variety of numerical simulations based on continuum medium models have been carried out in unsteady flows to explore the physical characteristics qualitatively. However, there still lack quantitative valid scales for these models, in which scale the solutions by simulation can be treated as physically credible. In this work, Euler and Navier-Stokes models are implemented on the typical unsteady flow with discontinuities: Sod shock tube problem. Firstly, based on the Boltzmann model whose valid scale is molecule kinetic scale, we compare the values of different moments of Euler and Navier-Stokes to Boltzmann with the evolution of flow. The results provide the valid scales of Euler and Navier-Stokes models quantitatively. Secondly, following the real conditions and parameters in real air, the physical characteristics of waves’ generation and evolution in Sod shock tube are observed and analyzed numerically at the microscopic level for the first time. Our results present the reference scales for the choice of minimal simulation scale in which the continuum medium models are used, and for the criteria whether the flow characteristics obtained by simulations can be treated as real physical characteristics.
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Journal Article Details
Publisher Name: Global Science Press
Language: English
DOI: https://doi.org/10.4208/cicp.OA-2018-0103
Communications in Computational Physics, Vol. 27 (2020), Iss. 2 : pp. 503–512
Published online: 2020-01
AMS Subject Headings: Global Science Press
Copyright: COPYRIGHT: © Global Science Press
Pages: 10
Keywords: Physical valid scale continuum model waves generation contact discontinuity thickness.