草原区植被对土壤风蚀影响的风洞模拟试验研究

Wind Tunnel Simulation Test on the Influence Factors of Wind Erosion in Grassland Areas

在前期研究的基础上,选择内蒙古乌兰察布荒漠草原区为研究区域,通过野外移动风洞模拟试验,开展荒漠草原植被对土壤风力侵蚀影响的定量化分析研究,旨在探讨不同植被盖度下空气动力学粗糙度的变化、不同植被盖度下的风沙流结构特征及植被盖度与风蚀输沙率的定量关系,从而为水土流失机理研究提供理论依据。试验研究表明:空气动力学粗糙度随着地表植被盖度的增加呈三次函数关系增加,拟合函数为Z0=ax3+bx2+cx+d;随着距地高度的增加,各层收集到的风蚀量呈不同程度降低,随着地表植被盖度的增加,各层输沙量也均降低;不同风速下植被盖度与风蚀输沙率之间呈幂函数相关。

Based on previous studies, selecting desert grasslands in the Ulanqab League of the Inner Mongolia as studied area, we carried out a quantitative analysis on influence of vegetation coverage on wind erosion by simulation test with a field mobile wind tunnel, which aimed at discussing the change of aerodynamic roughness and flow structure features under different vegetation coverage, and the quantitative relationship between vegetation coverage and sediment yield. Results show that aerodynamic roughness increases linearly approximately with the increase of vegetation coverage, and linear functional relationship is Z0=ax3＋bx2＋cx＋d. With the increasing of the height above the ground, sediment yield decreases. With the increase of vegetation coverage, sediment yield at each layer also reduces. Under different wind speeds, the relation between sediment yield of wind erosion and vegetation coverage is related by a power function. The conclusion will provide a theory basis for soil and water loss mechanism research.