Comparing theory and simulation for thermo-osmosis.

We report a numerical study of thermo-osmotic slip, i.e., the particle flux induced by a thermal gradient along a solid-fluid interface. To facilitate comparison with theory, we consider a model of an ideal but viscous gas. We compare three numerical routes to obtain the slip coefficient: (1) by using the Onsager reciprocity relations, (2) by using the appropriate Green-Kubo relation, and (3) via the excess enthalpy. The numerical results are found to be mutually consistent and to agree with the theoretical prediction based on the assumption that hydrodynamics and thermodynamics are locally valid.