A conceptual model of hysteresis

A conceptual model of the capillary hysteresis phenomenon is suggested. The advantage of this model is that all scanning curves are derived with the aid of simple functions from the main drying curve and the main wetting curves solely. Like the generalized approach of Enderby (1955) the present model takes into account a reversible part of the process. A simple method of predicting the first drying curve and the scanning curves branched out of the first drying curve is also proposed. Results based on this model are compared with laboratory measurements and the general Neel-Everett independent domain model. The comparison shows that the present model is often in more satisfactory agreement with measurements for cases in which the prediction based on the Neel-Everett model is poor. The suggested method can be used for solving problems in which hysteresis plays a significant role, the difficulties associated with laboratory determination of the ψ-θ relationships in the whole domain thus being avoided.