Hysteresis Affected Water Movement in Scale Heterogeneous Profiles

摘要

A method is presented for applying the concept of scale heterogeneity to infiltration and redistribution problems in heterogeneous porous materials. Where water movement is not monotonically constrained to either wetting or draining boundary curves, full soil water characteristics are needed to analyze the flow process numerically. Profile heterogeneity results in these characteristics becoming spatially dependent, with each position in the profile requiring its own set of soil water characteristics. Numerical techniques used to overcome the resulting problems of data storage and manipulation are outlined. These techniques include a simple interpolative soil water hysteresis model and a method of utilizing the dimensionless scaling factor to compute the requried soil water characteristics at any depth from a datum material. Results for unimpeded infiltration and redistribution and for infiltration into a bounded profile are compared with those for equivalent homogeneous profiles to demonstrate the utility of the method.