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Corners are actually super effective at moving liquid using surface tension (assuming the contact angle is such that the surface is concave). The key is that at the front of the liquid, where it's very thin in the corner, the surface has a small radius of curvature => low pressure. If there's a lot of fluid filling up a corner, the radius of curvature is large => high pressure. So fluid naturally flows into the corner. This is used a lot in space applications, e.g., for propellant management devices [1].

The first analysis of the effect I know of is a paper by Concus and Finn (1969) [2], who realized that fluid can be carried arbitrarily high in a triangular groove, even against gravity, and proposed that trees may use this mechanism to carry water to their highest reaches. (The catch is that the fluid front becomes thinner and thinner as it gets higher. And it starts breaking down when it gets so thin that the continuum limit no longer applies).

If you like math, I'd highly recommend checking out Mark Weislogel's research [3] which deals with the dynamics of viscous flow in triangular grooves.

Shameless plug: chapter 4 of my Ph.D. thesis [4] gives an introduction to the subject.

[1] http://www.pmdtechnology.com/PMD%20Physics.html

[2] https://doi.org/10.1073/pnas.63.2.292

[3] https://scholar.google.com/citations?user=rNOJ49QAAAAJ

[4] https://theses.hal.science/view/index/identifiant/tel-040155...




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