DSMC study of hypersonic rarefied flow using the Cercignani–Lampis–Lord model and a molecular-dynamics-based scattering database

This study proposes a scattering database method to model gas–solid interaction based on a database of distributions of scattering velocity obtained by a molecular dynamics simulation. The proposed method is used as the boundary condition in the direct simulation Monte Carlo method to simulate hyper...

Full description

Saved in:
Bibliographic Details
Published in:Physics of fluids (1994) 2021-07, Vol.33 (7)
Main Authors: Liu, Wenbin, Zhang, Jinbai, Jiang, Yazhong, Chen, Laiwen, Lee, Chun-Hian
Format: Article
Language:English
Subjects:
Boundary conditions
Conversion
Direct simulation Monte Carlo method
Flow simulation
Fluid dynamics
Hypersonic flow
Kinetic energy
Molecular dynamics
Physics
Rarefaction
Scattering
Simulation
Stagnation point
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This study proposes a scattering database method to model gas–solid interaction based on a database of distributions of scattering velocity obtained by a molecular dynamics simulation. The proposed method is used as the boundary condition in the direct simulation Monte Carlo method to simulate hypersonic flow over a rounded wedge at different Knudsen numbers (Kn). The effects of different wall models [e.g., the scattering database method and the Cercignani–Lampis–Lord (CLL) model] on the flow simulation were compared and analyzed. When Kn ≥ 1, the results based on the CLL model are evidently different from those of the scattering database model, where this difference increases with the degree of rarefication of flow. The mechanism of this discrepancy is such that when the flow is rarefied, a large number of freestream molecules from the far-field directly collide with the wall. In particular, near the stagnation point, the tangential reflection kinetic energy of freestream molecules is amplified due to the conversion of their normal incident kinetic energy. The scattering feature of this conversion is challenging to reproduce based on the theoretical framework of the CLL model. Still, a specific local parameter can describe the ratio of this conversion. Therefore, compared with the traditional wall model, the scattering database method can show more detailed scattering features and, hence, could be a promising tool for the study of gas–solid interaction in hypersonic rarefied flow.
ISSN:1070-6631
1089-7666
DOI:10.1063/5.0051969