Fig. 2. Examples of blue dye distribution for various locations in the columns and at different flow rates: (a) the distribution zone, (b) immediately above the capillary fringes, and (c) in the capillary fringes. The number of fingers formed was different for the various flow rates: (d) 1 cm h^–1 in Exp. I, (e) 2 cm h^–1 in Exp. I, and (f) for the column with hydrophobic sand in Exp. II.