Characteristics of instantaneous surface shear stress distribution at flexible plant surface

doi:10.7522/j.issn.1000-694X.2020.00048

Journal of Desert Research ›› 2020, Vol. 40 ›› Issue (5): 49-56.DOI: 10.7522/j.issn.1000-694X.2020.00048

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Characteristics of instantaneous surface shear stress distribution at flexible plant surface

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

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

Abstract

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

CLC Number:

X169

Liqiang Kang, Caiyun Li, Junjie Zhang, Xueyong Zou. Characteristics of instantaneous surface shear stress distribution at flexible plant surface[J]. Journal of Desert Research, 2020, 40(5): 49-56.

Figures/Tables 10

Fig.1 Plant model in wind tunnel

Fig.2 Measurement points around the plant

Fig.3 Variation of instantaneous surface shear stress with time

Fig.4 Comparison of surface shear stress at different plant densities (air flows from left to right)

Fig.5 Variation of mean value, standard deviation and relative standard deviation of surface shear stress in space with plant density and incoming wind speed

Fig.6 Space distribution of RMS fluctuation of surface shear stress

Fig.7 Variation of mean value, standard deviation and relative standard deviation of RMS fluctuation of surface shear stress in space with plant density and incoming wind speed

Fig.8 Space distribution of fluctuation intensity of surface shear stress

Fig.9 Variation of mean value, standard deviation and relative standard deviation of fluctuation intensity of surface shear stress in space with plant density and incoming wind speed

Fig.10 Probability density distribution of instantaneous surface shear stress at measurement points a and b

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Characteristics of instantaneous surface shear stress distribution at flexible plant surface

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