P. S. Raux, H. Cockenpot, M. Ramaioli, D. Quéré and C. Clanet, Wicking in a Powder, Langmuir, 29, 3636-3644, 2013, preprint
Imbibition can sometimes be beneficial for Agriculture and Inductry.
We measure the critical angle Θ* corresponding to the imbibition threshold.
Experimentally, the critical contact angle Θ* is found to be close to 51°, far from the value for capillary tubes (90°). Additionnaly, it does not depend on the size of the grains.