The dependent-domain theory of hysteresis developed here accounts for the effect of the pore-water blockage against air entry, while using the similarity hypothesis of the universal model (Mualem 1977). The resulting model is simpler and requires fewer data for calibration than previous dependent-domain models. Marked improvement is attained compared with the performance of the universal model.
Three porous media—glass beads, sand, and sandy loam for which detailed data are available—were used to test the model. Computed primary and secondary scanning curves derived by the new model are compared with corresponding experimental curves, as well as computed curves based on Model II of Mualem (1974) or Model III of Mualem and Dagan (1975). The new model seems to agree with observations much better that Model II, which uses the same amount of data for calibration. The accuracy of the computed results is comparable to that found for the dependent-domain model of Mualem and Dagan (1975), which requires more experimental data.