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中国沙漠 ›› 2020, Vol. 40 ›› Issue (5): 49-56.DOI: 10.7522/j.issn.1000-694X.2020.00048

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柔性植株地表瞬时地表剪应力分布特征

亢力强(), 李彩云, 张军杰, 邹学勇   

  1. 北京师范大学 地理科学学部 地表过程与资源生态国家重点实验室/防沙治沙教育部工程研究中心,北京 100875
  • 收稿日期:2020-03-31 修回日期:2020-05-11 出版日期:2020-09-28 发布日期:2020-09-28
  • 作者简介:亢力强(1976—),男,河北人,博士,研究方向为风沙物理。E-mail: kangliqiang@bnu.edu.cn
  • 基金资助:
    国家自然科学基金项目(41871003)

Characteristics of instantaneous surface shear stress distribution at flexible plant surface

Liqiang Kang(), Caiyun Li, Junjie Zhang, Xueyong Zou   

  1. State Key Laboratory of Earth Surface Processes and Resource Ecology / Engineering Center of Desertification and Blown-Sand Control of Ministry of Education,Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China
  • Received:2020-03-31 Revised:2020-05-11 Online:2020-09-28 Published:2020-09-28

摘要:

由于风的湍流性质,风对地表剪切作用而产生的地表剪应力是瞬态变化的。本文重点研究柔性植株地表植株周围瞬时地表剪应力的分布特征,为评估植株防风蚀作用提供参考。通过风洞实验,测量了在不同植株密度和不同来流风速下细长柔性植株覆盖地表上植株周围瞬时地表剪应力的空间分布。结果表明:柔性植株地表植株两侧地表剪应力增加,植株前后地表剪应力减小;随风速的增加,地表剪应力、均方根脉动地表剪应力的空间平均值和标准偏差均增加,而地表剪应力脉动强度的空间平均值和标准偏差均减小,它们在空间上的相对标准偏差基本不受风速的影响;随植株密度的增加,地表剪应力的空间平均值和标准偏差以及均方根脉动地表剪应力的空间平均值均减小,而地表剪应力在空间上的相对标准偏差、地表剪应力脉动强度的空间平均值和标准偏差均增大。

关键词: 瞬时地表剪应力, 柔性植株, 风洞实验

Abstract:

Surface shear stress caused by wind shear on the surface is instantaneous due to wind turbulence. This paper focuses on the study of distribution characteristics of instantaneous surface shear stress at the flexible plant surface in order to evaluate the plant protection against wind erosion. The space distribution of instantaneous surface shear stress at the slender flexible plant surface is measured at different plant densities and incoming wind speeds in a wind tunnel. The results show that the surface shear stress increases on both sides of the plant and decreases upwind and downwind of the plant. With the increase of incoming wind speed, the spatial mean value and standard deviation of surface shear stress and RMS surface shear stress fluctuation increase, while the spatial mean and standard deviation of fluctuation intensity of surface shear stress decrease, and their relative standard deviations in space are generally unaffected by wind speed. With the increase of plant density, the spatial mean value and standard deviation of surface shear stress decrease, and the spatial mean value of RMS surface shear stress fluctuation also decreases, while the relative standard deviation of surface shear stress in space and the spatial mean value and standard deviation of fluctuation intensity of surface shear stress increase.

Key words: instantaneous surface shear stress, flexible plant, wind tunnel experiment

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