Interfaces determined by capillarity and gravity in a two-dimensional porous medium

Maria Calle¹ ; Carlota Maria Cuesta² ; Juan J.L. Velázquez³ 

¹Universidad Carlos III, Madrid-Getafe, Spain
²Universidad del Pais Vasco, Bilbao, Spain
³Universität Bonn, Germany

Interfaces and free boundaries, Tome 18 (2016) no. 3, pp. 355-391

Résumé

We consider a two-dimensional model of a porous medium where circular grains are uniformly distributed in a squared container. We assume that such medium is partially filled with water and that the stationary interface separating the water phase from the air phase is described by the balance of capillarity and gravity. Taking the unity as the average distance between grains, we identify four asymptotic regimes that depend on the Bond number and the size of the container. We analyse, in probabilistic terms, the possible global interfaces that can form in each of these regimes. In summary, we show that in the regimes where gravity dominates the probability of configurations of grains allowing solutions close to the horizontal solution is close to one. Moreover, in such regimes where the size of the container is sufficiently large we can describe deviations from the horizontal in probabilistic terms. On the other hand, when capillarity dominates while the size of the container is sufficiently large, we find that the probability of finding interfaces close to the graph of a given smooth curve without self-intersections is close to one.

Détail

DOI : 10.4171/ifb/367

Classification : 35-XX, 60-XX, 76-XX
Mots-clés : Capillarity-gravity interface, two-dimensional porous medium, probabilistic asymptotic analysis