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| Titel |
A Bézier-Spline-based Model for the Simulation of Hysteresis in Variably Saturated Soil |
| VerfasserIn |
Clemens Cremer, Aaron Peche, Luisa-Bianca Thiele, Thomas Graf, Insa Neuweiler |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250152531
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| Publikation (Nr.) |
 EGU/EGU2017-17377.pdf |
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| Zusammenfassung |
| Most transient variably saturated flow models neglect hysteresis in the p$_c$-S-relationship (Beven, 2012). Such models tend to inadequately represent matrix potential and saturation distribution. Thereby, when simulating flow and transport processes, fluid and solute fluxes might be overestimated (Russo et al., 1989). In this study, we present a simple, computationally efficient and easily applicable model that enables to adequately describe hysteresis in the p$_c$-S-relationship for variably saturated flow. This model can be seen as an extension to the existing play-type model (Beliaev and Hassanizadeh, 2001), where scanning curves are simplified as vertical lines between main imbibition and main drainage curve. In our model, we use continuous linear and B\'{e}zier-Spline-based functions. We show the successful validation of the model by numerically reproducing a physical experiment by Gillham, Klute and Heermann (1976) describing primary drainage and imbibition in a vertical soil column. With a deviation of ~3\%, the simple B\'{e}zier-Spline-based model performs significantly better that the play-type approach, which deviates by ~30\% from the experimental results. Finally, we discuss the realization of physical experiments in order to extend the model to secondary scanning curves and in order to determine scanning curve steepness. \\ \\
{\bf Literature} \\ \\
Beven, K.J. (2012). Rainfall-Runoff-Modelling: The Primer. John Wiley and Sons. \\ \\
Russo, D., Jury, W. A., & Butters, G. L. (1989). Numerical analysis of solute transport during transient irrigation: 1. The effect of hysteresis and profile heterogeneity. Water Resources Research, 25(10), 2109--2118. https://doi.org/10.1029/WR025i010p02109. \\ \\
Beliaev, A.Y. & Hassanizadeh, S.M. (2001). A Theoretical Model of Hysteresis and Dynamic Effects in the Capillary Relation for Two-phase Flow in Porous Media. Transport in Porous Media 43: 487. doi:10.1023/A:1010736108256. \\ \\
Gillham, R., Klute, A., & Heermann, D. (1976). Hydraulic properties of a porous medium: Measurement and empirical representation. Soil Science Society of America Journal, 40(2), 203--207. |
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