如何定义边界条件:低渗透的脸和单元梯度的土壤体积含水量?- 江南体育网页版- - - - -地球科学堆江南电子竞技平台栈交换 最近30从www.hoelymoley.com 2023 - 07 - 07 - t22:27:22z //www.hoelymoley.com/feeds/question/24159 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/24159 3 如何定义边界条件:低渗透的脸和单元梯度的土壤体积含水量? 此前阿玛尼 //www.hoelymoley.com/users/20807 2022 - 08 - 13 - t16:27:28z 2022 - 12 - 09 - t05:54:09z < p >背景:模型模拟土壤水的流动(如陆地表面模型)< / p > < p >在这些模型中,为了模拟渗流(/排水)从土壤的底部定义列,我们需要定义一个较低的边界条件。两个选项我见到在文献中是一个渗流梯度条件(SF)和单位。< / p > < p >是它正确定义这两个如下:< / p > < ul > <李>科幻:渗流发生只有最后一层土壤中列是饱和。李李< / > < > UG:渗流发生只有底部的土壤含水量的列大于土壤含水量在田间持水量。< /李> < / ul > < p >我已被告知,因为科幻和UG定义基于吸而不是土壤水分,上述定义在技术上都不正确。< / p > < p >请让我知道你的想法,谢谢。< / p > <人力资源/ > < p >更多上下文:模型计算土壤的渗透从底部列使用1 d Darcian流动方程,由水分含量值(最后一层)阈值。这就是为什么我需要定义基于含水量较低的边界。< / p > //www.hoelymoley.com/questions/24159/-/24604 # 24604 2 Mortsde回答的如何定义边界条件:低渗透的脸和单元梯度的土壤体积含水量? Mortsde //www.hoelymoley.com/users/5475 2022 - 12 - 09 - t05:54:09z 2022 - 12 - 09 - t05:54:09z < p > 8月以来已经好几个月,但也许别人会发现这很有用。< / p > < p >像很多问题在水文-适当的边界条件定义为准确描述地下系统。如果有限的数据可用,最好运行边界条件和假设的敏感性和然后确定条件的保守的回答是合理的(可能与更详细的描述修改后)。< / p > < p >的边界条件:< / p > < p >渗流脸需要底层达到饱和之前,水可以传输到一个较低的水平或逃避一个模型。This would only be appropriate if there was a realistic interface at the bottom layer of the model that would promote ponding and then water were to "punch through" that layer in the event the soil directly above the layer became saturated.

A free draining boundary will assume the water can continue moving vertically at a unit gradient with the elements above. This assumption is good if the depth to a water table or some kind of low-permeability zone is quite a ways below a model area of interest.

So - without knowing more about the particulars of your analysis, I'd expect a free draining boundary condition would be an ok starting point. Again, probably worth a sensitivity analysis when in doubt.
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