Dynamics of Gas Molecule near the Surface in Rarefied Flow

Research Project

Project/Area Number	09450074
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	Fluid engineering
Research Institution	Yokohama National University
Principal Investigator	MATSUI Jun Yokohama National Univ., Faculty of Eng., Assistant Professor, 工学部, 助教授 (40251756)
Co-Investigator(Kenkyū-buntansha)	MATSUMOTO Yoichiro Univ.of Tokyo, Faculty of Eng., Professor, 工学部, 教授 (60111473)
Project Period (FY)	1997 – 1998
Project Status	Completed (Fiscal Year 1998)
Budget Amount *help	¥8,200,000 (Direct Cost: ¥8,200,000) Fiscal Year 1998: ¥1,600,000 (Direct Cost: ¥1,600,000) Fiscal Year 1997: ¥6,600,000 (Direct Cost: ¥6,600,000)
Keywords	rarefied flow / gas surface interaction / diffuse scattering / boundary condition / molecular dynamics / 表面散乱 / 付着分子 / DSMC法 / Maxwellモデル
Research Abstract	1) Using the molecular-dynamics simulation method, the scattering process of gas molecule on the surface with adsorbale gas molecules. There are 4 patterns of scattering process, that associated with the distribution of energy-transfer from gas molecule to other molecules. The parameters such as mass ratio of gas molecule, potential coefficients, number of adsorbate on surface are changed in the simulation, and their dependency on the scattering process is studied. 2) To study the sticking and escaping dynamics of gas molecule in thermal equilibrium stale, the behavior of Xenon molecules between two plate of Platinum are simulated for a long period. The escaping process has three types. Two of them are caused by interaction from adsorbated gas molecule. Also the dependency of escaping molecules on the coverage coefficients are studied. 3) The effrect of roughness of the surface to rarefied gas flow is estimated by "Direct Simulation Monte Carlo" method. The test case is Couette flow between two plates. One plate has some roughness that simulate the shape made by cutting bite of the lathe. With high Knudsen number, the effect of roughness reaches to all the flow field by some vortex structure at the sharp edge of roughness. The parameter study is done on the height of roughness, angle of bite, and Knudsen number.