A conceptual model of hysteresis

Abstract

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 Néel‐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 Néel‐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.

Sensitivity analysis of CFD coupled non-isothermal heat and moisture modelling

“…Therefore a hysteresis model based on the 'ink bottle effect' was included in the coupled CFD-HAM model. This model was originally proposed by Mualem [22] and then later simplified by Milly [23]. A more detailed explanation of this model is found in [12].…”

Modeling and field evidence of finger formation and finger recurrence in a water repellent sandy soil

“…To describe capillary hysteresis, a number of alternative models could be applied. In this paper we apply the independent domain model of Mualem [1974].…”

Modelling soil water dynamics in the unsaturated zone -state of the art

“…He solved the problem (see also POULAVASSILIS and CHILDS, 1971) by Jntroducing a domain dependenee factor, so that the drying and wetting of single pore was made dependent on the neighbouring pore status. MUALEM (1974) introduced a model to compute hysteresis, based on the independent domain principle. In 1984, he defined a domain dependenee factor as the ratio between the volume of pores actually emptied and the volume which could have been emptied if all the pores would receive enough air from neighbouring pores.…”