Figure 3

(a) Magnified image of granular medium made of glass beads with PSZ and fully wet region. There is a difference in meniscus volume along the vertical direction that induces capillary pressure. (b) Experimental image showing water flow along the length of the inserted intrusion. (c) Illustration of the continued capillary rise in the vicinity of the intrusion when inserted in the 2D cell filled only with water (no beads). (d) Experimental series of images showing the evolution of the front and the water distribution in the presence of two intrusion geometries, circular and square. (e) Water mass loss curve (evaporation) for the 2D porous medium with insertions of two different geometries of the solid rods. These are compared to the mass curve obtained for a typical 2D cell without intrusion. In these experiments, the size of the beads is d = 500 μm. (f) Illustration of the 2D wet granular heterogeneous media consisting of a granular column of d = 500 μm surrounded by d = 1 mm. Experimental images of evaporation experiments of the same system showing a saturated column of d = 500 μm while a PSZ develops in the medium of d = 1 mm.