Characteristics of the second stage of evaporation and water redistribution through double layered sandy soil profiles
Characteristics of the second stage of evaporation and water redistribution through double layered sandy soil profiles
复制标题
双层沙土剖面第二阶段蒸发及水分再分配特征
DOI：
--
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
N. Yasufuku
中科院分区：
文献类型：
--
作者：
Adel Alowaisy;N. Yasufuku
多孔介质的蒸发涉及复杂的孔隙尺度水和蒸汽传输，直接影响液相分布和通量。多层型材中纹理对比边界的存在增加了复杂性。本研究旨在通过双层土壤剖面评估纹理对比边界深度和单层厚度对实际蒸发和储水的影响。对于覆盖在粗细砂上的细砂，发现顶层小毛细管导致了在下降速率阶段损失的大部分水。考虑到细覆盖的粗砂剖面，由于顶部细层内吸力的增加，在干燥前沿到达结构边界之前，从底部粗层到顶部细层的泵送现象发生。双层土壤剖面的储水能力很大程度上取决于顶部到底部的小毛细管比率乘以层厚度比率。无论大气条件和分层顺序如何，得出的结论是，结构对比边界越浅，导致实现残余蒸发阶段所需的总持续时间减少，从而导致通过第一和第二蒸发阶段的更高的储水能力。
Evaporation from porous media involves a complex pore scale water and vapor transportation that directly affects the liquid phase distribution and fluxes. The presence of textural contrast boundary in multilayered profiles adds to the complexity. This study aims at evaluating the textural contrast boundary depth and individual layer thickness influence on the actual evaporation and water storage through double-layered soil profiles. For coarse overlying fine sand, it was found that the top layer small capillaries contribute to the majority of water lost through the falling rate stage. Considering fine overlying coarse sand profiles, the pumping phenomenon from the bottom coarse layer to the top fine layer occurs before the arrival of the drying front to the textural boundary due to the increasing suction forces within the top fine layer. The water storage capability of double layered soil profiles depends highly on the top to the bottom small capillaries ratio multiplied by the layer thickness ratio. Regardless the atmospheric conditions and layering sequence, it was concluded that the shallower the textural contrast boundary results in decreasing the total duration required to achieve the residual evaporation stage thus leads to higher water storage capabilities through the first and second evaporation stages.