نتایج جستجو برای: genuchten
تعداد نتایج: 254 فیلتر نتایج به سال:
Heat and mass transfer in steaming ground have been modeled using the TOUGH2 geothermal simulator and the results compared with field data collected by Bromley and Hochstein (2001). They measured temperatures at several sites over periods of 4 to 7 days at the soil surface, and depths of 0.01 m, 0.05 m, 0.10 m, 0.15 m, and 0.20 m. Soil porosities and saturations were also measured. These data s...
Martinus Th. (“Rien”) van Genuchten has been awarded the 2023 Wolf Prize in Agriculture. The is to “outstanding scientists and artists from around world for achievements interest of humanity friendly relations among people.” prize disciplines medicine, agriculture, mathematics, chemistry, physics. For agricultural sciences, widely considered one world's most prestigious recognitions. Rien was b...
Direct measurement of soil unsaturated hydraulic conductivity (K(h) or K(θ)) is difficult and time-consuming, and often in many applied models, predicting hydraulic conductivity is carried out according to measurements of soil retention curve and saturated hydraulic conductivity (Ks). However, using KS as a matching point in many procedures may result in over-estimation of unsaturated hydraulic...
Several existing equations for solving the non-linear soil-hydraulic properties are introduced and validated to field and laboratory measured data. Models for non-linear hydraulic properties of unsaturated porous media arise from statistical and mathematical fit through the measured data and they can be expressed in forms of unsaturated permeability versus either pressure head or volumetric moi...
To understand the hydraulic properties of soils, accurate prediction of unsaturated hydraulic conductivity is needed which is commonly derived from the soil water release characteristic. In fine-textured soils the modified Mualem-van Genuchten (MMVG) function has been used extensively to predict the change in relative conductivity with changes in matric potential, but this assumes that the soil...
abstract water retention curve (wrc) is a fundamental property of soil. it is used to evaluate available water, permeability, drainage and movement of solutes. despite numerous studies on wrc of soils abroad, no local study has been carried out on charmahal-va-bakhtiari soils. the objective of this study was to compare the quality of fitting of several wrc models to lordegan soils and to select...
to examine hydraulics of lnapls in soil, the retention curves of diesel fuel and water were both determined by hanging column method. the soil retention parameters were obtained based on van genuchten, brooks-corey and campbell’s models. in addition, the soil hydraulic conductivity for both fluids were predicted based on mualem- brooks-corey, burdine- brooks-corey, mualem-van genuchten and camp...
In this paper we discuss the numerical modelling of two inverse problems in porous media flow. In the first problem, we determine the soil parameters that occur in the retention and hydraulic permeability curves of the Van Genuchten ansatz for Richard’s equation. In the second problem we determine the hydraulic permeability, longitudinal dispersivity and adsorption isotherms using the measureme...
According to the Mualem capillary model, hydraulic conductivity (HC) is integrated theoretically from the function related to soil water retention curves (SWRC). On the other hand, based on the smooth type of SWRC, the predicted HC function decreases abruptly near saturation, which often challenges the stability of numerical solutions. To improve the Mualem HC, van Genuchten’s function for SWRC...
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