Molecular free path distribution in rarefied gases

Nishanth Dongari (1) , Yonghao Zhang (1) , Jason M Reese (1)

1 Department of Mechanical Engineering

We present the results of investigations into the distribution of molecular free paths in rarefied gases using molecular dynamics simulations. Our tests on a range of different gas densities and confinements (unbounded, single bounding wall, and parallel bounding walls) indicate that the molecules perform Lévy-type flights, irrespective of the presence of a bounding wall. The free paths most closely follow a power-law distribution. Simulations of gases confined by planar surfaces indicate that the local molecular mean free path varies sharply close to a solid surface. These results may yield new insight into diffusive transport in rarefied gases, in particular, the constitutive behaviour of gas flows in micro and nanoscale devices.

Keywords: 47.45.-n; 47.61.Cb; 47.11.Mn

Nishanth Dongari, Yonghao Zhang, Jason M Reese. Molecular free path distribution in rarefied gases. Journal of Physics D: Applied Physics, 2011, 44 (12), pp.125502. ⟨10.1088/0022-3727/44/12/125502⟩. ⟨hal-00604892⟩