Numerical analysis of capillary bridges and coalescence in a triplet of spheres

The behavior of a natural soil is known to change substantially in presence water under unsaturated conditions, due additional capillary forces. Water can be absorbed by hygroscopic particles (such as clay), or remains at the surface solid grains (sand, silt) and forms either discontinuous (pendular regime) continuous phase (funicular regime), depending on content soil. Capillary bridges exist solely between pairs small contents, giving rise simple force expressions straightforward subsequent modeling. For larger these generic progressively merge into more complex coalesced involving several (i.e. least three) whose description little known. In present study, numerical approach based energy minimization proposed compute forces for assemblies two three grains. methodology first validated standard bridge comparison both with previous experiments other alternative theoretical approaches. method next extended triplet within wide range (or equivalently reduced volume) during imbibition, switch from uncoalesced bridges. Eventually, influence contact angle, tension gravity force, volume coalescence morphology well investigated. study paves way implementation effects micromechanical models relying mesostructures composed few