Evaluating the optimal porosity of fences for reducing wind erosion  

作　　者：ZhiBao Dong WanYin Luo GuangQiang Qian HongTao Wang 

机构地区：[1]Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China

出　　处：《Research in Cold and Arid Regions》2011年第1期1-12,共12页寒旱区科学（英文版）

基　　金：funding from the Knowledge Innovation Project of the Chinese Academy of Science(KZCX2-YW-329);the National Natural Science Foundation of China (40638038)

摘　　要：Porosity is the most important parameter determining the shelter efficiency of fences. Wind measurements were made around fence models with different porosities in a wind tunnel. The optimal fence porosity is evaluated by means of Gandemer＇s method that combines the effects of wind reduction and turbulence fields on the shelter efficiency for abating wind erosion. Defining the optimal porosity must take into account of its own purposes, required shelter degree and area to be sheltered. Turbulence has profound impacts on the shelter efficiency of high degree. Two concepts： absolute optimal porosity and practical optimal porosity concerning optimal porosity are proposed. Choosing the practical optimal porosity means reducing cost without significant expense of shelter efficiency. According to the evaluation in present study, the absolute optimal porosity for providing high degree of shelter to abate wind erosion is 0.20 while the practical optimal porosity is around 0.40. Ifa less shelter degree but over wider area is required, the absolute optimal porosity ranges from 0.05 to 0.10 and the practical optimal porosity is 0.10. For any degree of shelter for abating wind erosion effectively, the fence porosity must be less than or equal 0.40.Porosity is the most important parameter determining the shelter efficiency of fences. Wind measurements were made around fence models with different porosities in a wind tunnel. The optimal fence porosity is evaluated by means of Gandemer＇s method that combines the effects of wind reduction and turbulence fields on the shelter efficiency for abating wind erosion. Defining the optimal porosity must take into account of its own purposes, required shelter degree and area to be sheltered. Turbulence has profound impacts on the shelter efficiency of high degree. Two concepts： absolute optimal porosity and practical optimal porosity concerning optimal porosity are proposed. Choosing the practical optimal porosity means reducing cost without significant expense of shelter efficiency. According to the evaluation in present study, the absolute optimal porosity for providing high degree of shelter to abate wind erosion is 0.20 while the practical optimal porosity is around 0.40. Ifa less shelter degree but over wider area is required, the absolute optimal porosity ranges from 0.05 to 0.10 and the practical optimal porosity is 0.10. For any degree of shelter for abating wind erosion effectively, the fence porosity must be less than or equal 0.40.

关 键 词：WINDBREAK shelter efficiency optimal design 

分 类 号：S157.1[农业科学—土壤学] P618.130.2[农业科学—农业基础科学]