A multiplicative decomposition of Poiseuille number on rarefaction and roughness by lattice Boltzmann simulation

作者：Liu Chaofeng; Yang Jidong; Ni Yushan^*

来源：Computers & Mathematics with Applications, 2011, 61(12): 3528-3536.

DOI：10.1016/j.camwa.2010.03.030

• Friction factor
• Rarefaction effect
• Roughness effect
• Lattice Boltzmann method

Poiseuille number of rarefied gas flow in channels with designed roughness is studied and a multiplicative decomposition of Poiseuille number on the effects of rarefaction and roughness is proposed. The numerical methodology is based on the mesoscopic lattice Boltzmann method. In order to eliminate the effect of compressibility, the incompressible lattice Boltzmann model is used and the periodic boundary is imposed on the inlet and outlet of the channel. The combined bounced condition is applied to simulate the velocity slip on the wall boundary. Numerical results reveal the two opposite effects that velocity gradient and friction factor near the wall increase as roughness effect increases; meanwhile, the increments of the rarefaction effect and velocity slip lead to a corresponding decrement of friction factor. An empirical relation of Poiseuille number which contains the two opposite effects and has a better physical meaning is proposed in the form of multiplicative decomposition, and then is validated by available experimental and numerical results.

• 出版日期2011-6
• 单位上海机电工程研究所; 复旦大学