SIMULATION OF UNSATURATED WATER-FLOW AROUND OBSTRUCTIONS - 3-DIMENSIONAL RANKINE BODIES

Sink and source combinations were used to simulate flow around barrier s such as might exist within a stony, unsaturated soil system. Althoug h more complicated than two-dimensional cases which were previously pr esented, the three-dimensional ''Rankine bodies'' are more appropriate for simulating flow around real objects. Generally, the appropriate p otentials and velocity fields are easy to write down and evaluate, in fact, much easier than the alternative solutions based on scattering t heory. Also, arrays of bodies can be arranged to simulate a repeated p attern rather than deal with only single barriers, cavities, etc. Howe ver, the shapes of the bodies are not known ahead of time and can only be roughly controlled. For the same Darcian flow, a simulated stony l ayer was shown to be wetter than that without stones and the effective saturated conductivity reduced somewhat less than 1 - f(s) where f(s) is the fraction of stones. Overall there is a qualitative agreement w ith previous theoretical and experimental results for both saturated a nd unsaturated flow. Copyright (C) 1996 Elsevier Science Ltd