Talk:Thermal transpiration

Incorrect representation of forces

The discussion in terms of "forces" does not make much sense, one needs to consider "stresses", more precisely the shear stress tangential to the surface, which correspond to the tangential component of the forces from the hot and the cold. The "combined force" is rather misleading, its normal component is the ordinary pressure of the gas which is constant everywhere, independent of temperature (!) The interesting bit is the tangential component of the "combined force", the density of which corresponds to the mentioned shear stress. It's all in Maxwell's paper. — Preceding unsigned comment added by 147.210.116.130 (talk) 08:59, 7 July 2023 (UTC)[reply]

Unclear language re: pressure difference?

From the current text of the article: "Thermal transpiration causes a flow of gas in the absence of any pressure difference, and is able to maintain a certain pressure difference called thermomolecular pressure difference in a steady state." It's unclear from this whether or not there's a pressure difference due to thermal transpiration. Perhaps it should read "...in the absence of any other pressure difference..."? I'm not sufficiently familiar with the physics here to know the answer offhand. DrPippy (talk) 15:01, 27 February 2023 (UTC)[reply]