The dust emission law in the wind erosion process on soil surface |
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Authors: | Mao Xing and LieJin Guo |
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Institution: | (1) Mining Technology Institute, Taiyuan University of Technology, Taiyuan, 030024, China;(2) State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049, China |
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Abstract: | The dust emission models to date cannot describe the relation between the transport rate of different sized grains and their
grain size composition in soil surface, so Aeolian grain transport on a soil-like bed composed of fine sand and silt powder
was measured in a wind tunnel. Six types of soil-like beds with different silt fractions have been tested in this experiment.
The mass flux profiles of silt dust and sand grains are much different due to their different motion modes. Analysis of the
vertical distribution of the powder and sand grains reveals that for a given soil bed, the ratio of the horizontal dust flux
to the horizontal sand flux is directly proportional to their mass ratio in the bed. The dust flux is closely linked to the
sand flux by the bombardment mechanism. For a given wind velocity and grain size of the bed, the slopes of the vertical mass
flux profiles of sand grains larger than 100 μm are nearly equal in a log-linear plot and the ratio between the fraction of
transport rate of each size group to the whole transport rate and the mass fraction of each size group in the bed is a constant
only dependent on grain size. With this law, the transport rate of dust and different sized grains can be related with the
grain size composition in the soil surface.
Supported by the National Natural Science Foundation of China (Grant No. 50706031) and the Natural Science Foundation of Shanxi
Province of China (Grant No. 2008021005) |
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Keywords: | wind erosion dust transport rate grain size |
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