Solutions of Young-Laplace equation for partially saturated porous media. Stability analysis of capillary bridges

In this work, we propose an original resolution of Young-Laplace equation for capillary doublets from an inverse problem. We establish a simple explicit criterion based on the observation of the contact point, the wetting angle and the gorge radius, to classify in an exhaustive way the nature of the surface of revolution. The true shape of the admissible static bridges surface is described by parametric equations; this way of expressing the profile is practical and well efficient for calculating the binding forces, areas and volumes. A stability analysis of the resulting capillary bridges, revisited through Vogel's stability criteria, is also developed.