TY - JOUR
T1 - Dynamic capillary pressure during water infiltration
T2 - Experiments and Green-Ampt modeling
AU - Pellichero, Emanuele
AU - Glantz, Roland
AU - Burns, Meghan
AU - Mallick, Debjani
AU - Hsu, Shao Yiu
AU - Hilpert, Markus
PY - 2012
Y1 - 2012
N2 - In a recent study by Hsu and Hilpert (2011), the Green-Ampt (GA) model for water infiltration was modified to account for a dynamic capillary pressure that depends on the wetting front velocity. In that study, the only transient flow, to which the modified GA approach was compared, was capillary rise. In this paper, transient downward infiltration experiments were performed using three different ponding depths. We demonstrated that infiltration can be effectively modeled using the modified GA approach. The parameters of the dynamic capillary pressure relationship were fitted and independent of the ponding depth. Furthermore, the experimental data could not be described accurately at early times with the classical GA approach. This was particularly evident when plotting the product between the Darcy velocity and the wetting front position against the wetting front position. In these plots, the initial unphysical infinite rate of infiltration, that occurs in the classical GA model, appears to be a primary element of inaccuracy. It was furthermore verified that the limited ability of the classical GA approach to describe the experimental data is not related to inertial forces arising during the initial phase of infiltration.
AB - In a recent study by Hsu and Hilpert (2011), the Green-Ampt (GA) model for water infiltration was modified to account for a dynamic capillary pressure that depends on the wetting front velocity. In that study, the only transient flow, to which the modified GA approach was compared, was capillary rise. In this paper, transient downward infiltration experiments were performed using three different ponding depths. We demonstrated that infiltration can be effectively modeled using the modified GA approach. The parameters of the dynamic capillary pressure relationship were fitted and independent of the ponding depth. Furthermore, the experimental data could not be described accurately at early times with the classical GA approach. This was particularly evident when plotting the product between the Darcy velocity and the wetting front position against the wetting front position. In these plots, the initial unphysical infinite rate of infiltration, that occurs in the classical GA model, appears to be a primary element of inaccuracy. It was furthermore verified that the limited ability of the classical GA approach to describe the experimental data is not related to inertial forces arising during the initial phase of infiltration.
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U2 - 10.1029/2011WR011541
DO - 10.1029/2011WR011541
M3 - Article
AN - SCOPUS:84862563342
SN - 0043-1397
VL - 48
JO - Water Resources Research
JF - Water Resources Research
IS - 6
M1 - W06515
ER -