Experimental Study of Water Infiltration in Unsaturated Horizontal Sand Columns under Various Air Confinement Conditions

Figure 2

Visual imaging of the infiltration process in Expts. #1-#3. All snapshots show the general distribution of the saturated zone (red dotted line), transition zone (green dotted line), and unchanged zone (yellow dotted line) at the times that the wetting front reaches the positions P₁-P₃.