| DOI: | 10.2172/1039925
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| 报告号: | LBNL-5358E
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| 报告题名: | Optimality and Conductivity for Water Flow: From Landscapes, to Unsaturated Soils, to Plant Leaves |
| 作者: | Liu, H.H.
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| 出版年: | 2012
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| 发表日期: | 2012-02-23
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| 国家: | 美国
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| 语种: | 英语
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| 中文主题词: | 土壤
; 渗透系数
; 景观
; 水力传导系数
; 导电性
; 重力
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| 主题词: | SOILS
; HYDRAULIC CONDUCTIVITY
; LANDSCAPE
; CONDUCTIVITY
; GRAVITY
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| 英文摘要: | Optimality principles have been widely used in many areas. Based on an optimality principle that any flow field will tend toward a minimum in the energy dissipation rate, this work shows that there exists a unified form of conductivity relationship for three different flow systems: landscapes, unsaturated soils and plant leaves. The conductivity, the ratio of water flux to energy gradient, is a power function of water flux although the power value is system dependent. This relationship indicates that to minimize energy dissipation rate for a whole system, water flow has a small resistance (or a large conductivity) at a location of large water flux. Empirical evidence supports validity of the relationship for landscape and unsaturated soils (under gravity dominated conditions). Numerical simulation results also show that the relationship can capture the key features of hydraulic structure for a plant leaf, although more studies are needed to further confirm its validity. Especially, it is of interest that according to this relationship, hydraulic conductivity for gravity-dominated unsaturated flow, unlike that defined in the classic theories, depends on not only capillary pressure (or saturation), but also the water flux. Use of the optimality principle allows for determining useful results that are applicable to a broad range of areas involving highly non-linear processes and may not be possible to obtain from classic theories describing water flow processes. |
| URL: | http://www.osti.gov/scitech/servlets/purl/1039925
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| Citation statistics: |
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| 资源类型: | 研究报告
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/40742
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| Appears in Collections: | 过去全球变化的重建
影响、适应和脆弱性
科学计划与规划
气候变化与战略
全球变化的国际研究计划
气候减缓与适应
气候变化事实与影响
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| 1039925.pdf（359KB） | 研究报告 | -- | 开放获取 | | View
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| Recommended Citation: | |
Liu, H.H.. Optimality and Conductivity for Water Flow: From Landscapes, to Unsaturated Soils, to Plant Leaves. 2012-01-01.
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