open access

https://hdl.handle.net/2115/93014

Couette flow at high Knudsen number between wall and liquid boundaries

英語

2023-08-28

American Institute of Physics

Physics of Fluids

35(8)

082021

This paper presents molecular dynamics simulations of the Couette flow of a rarefied gas between the liquid and wall boundaries and, in particular, investigates the boundary conditions for the Boltzmann equation at the liquid interface. The simulation results for various Knudsen numbers show that the slip velocity decreases at the liquid boundary and increases at the smooth wall as the Knudsen number increases, indicating that the velocity profile of the rarefied Couette flow is asymmetric. One reason for this is backscattering, in which molecules are reflected in the opposite direction to the mainstream flow, owing to molecular-scale roughness at the liquid boundary. It has also been suggested that the backscattering effect decreases when the gas density increases. This can be understood using the local Knudsen numbers near the liquid boundary.

学術雑誌論文

Version of Record

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Kazumichi Kobayashi, Kota Aoki, Hirofumi Tabe, Hiroyuki Fujii, Toshiki Nara, Hideyoshi Takashima, Nobuyuki Oshima, Masao Watanabe; Couette flow at high Knudsen number between wall and liquid boundaries. Physics of Fluids 1 August 2023; 35 (8): 082021. and may be found at https://doi.org/10.1063/5.0164544

1070-6631