Moment analysis description of wetting and redistribution plumes in wettable and water-repellent soils

TY - JOUR

T1 - Moment analysis description of wetting and redistribution plumes in wettable and water-repellent soils

AU - Xiong, Yunwu

AU - Furman, Alex

AU - Wallach, Rony

N1 - Funding Information: This research was supported by research Grant US-3662-05R from BARD, the United States-Israel Binational Agricultural Research and Development Fund.

PY - 2012/2/23

Y1 - 2012/2/23

N2 - Water repellency has a significant impact on water flow patterns in the soil profile. Transient 2D flow in wettable and natural water-repellent soils was monitored in a transparent flow chamber. The substantial differences in plume shape and spatial water content distribution during the wetting and subsequent redistribution stages were related to the variation of contact angle while in contact with water. The observed plumes shape, internal water content distribution in general and the saturation overshoot behind the wetting front in particular in the repellent soils were associated with unstable flow. Moment analysis was applied to characterize the measured plumes during the wetting and subsequent redistribution. The center of mass and spatial variances determined for the measured evolving plumes were fitted by a model that accounts for capillary and gravitational driving forces in a medium of temporally varying wettability. Ellipses defined around the stable and unstable plumes' centers of mass and whose semi-axes represented a particular number of spatial variances were used to characterize plume shape and internal moisture distribution. A single probability curve was able to characterize the corresponding fractions of the total added water in the different ellipses for all measured plumes, which testify the competence and advantage of the moment analysis method.

AB - Water repellency has a significant impact on water flow patterns in the soil profile. Transient 2D flow in wettable and natural water-repellent soils was monitored in a transparent flow chamber. The substantial differences in plume shape and spatial water content distribution during the wetting and subsequent redistribution stages were related to the variation of contact angle while in contact with water. The observed plumes shape, internal water content distribution in general and the saturation overshoot behind the wetting front in particular in the repellent soils were associated with unstable flow. Moment analysis was applied to characterize the measured plumes during the wetting and subsequent redistribution. The center of mass and spatial variances determined for the measured evolving plumes were fitted by a model that accounts for capillary and gravitational driving forces in a medium of temporally varying wettability. Ellipses defined around the stable and unstable plumes' centers of mass and whose semi-axes represented a particular number of spatial variances were used to characterize plume shape and internal moisture distribution. A single probability curve was able to characterize the corresponding fractions of the total added water in the different ellipses for all measured plumes, which testify the competence and advantage of the moment analysis method.

KW - Drip irrigation

KW - Moment analysis

KW - Unstable flow

KW - Water-repellent soil

UR - http://www.scopus.com/inward/record.url?scp=84856379973&partnerID=8YFLogxK

U2 - 10.1016/j.jhydrol.2011.12.010

DO - 10.1016/j.jhydrol.2011.12.010

M3 - 文章

AN - SCOPUS:84856379973

SN - 0022-1694

VL - 422-423

SP - 30

EP - 42

JO - Journal of Hydrology

JF - Journal of Hydrology

ER -