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通过对河北昌黎黄金海岸沙丘风沙流的野外实地观测与室内风洞模拟实验数据的数值模拟,探讨了我国典型海岸沙丘风沙流中不同粒径组沙粒输沙量的垂向分布模式。结果表明,河北昌黎黄金海岸沙丘表面风沙流中不同粒径组沙粒输沙量的垂向分布特征并不一致,其中细沙和中沙符合典型的指数递减分布规律,但粗沙则为负幂函数分布。究其原因,主要与不同粒径组沙粒输沙量的分布高度及运动方式差异有关。在实际非均匀沙床面上,粗沙主要集中分布于沙丘表面4cm高度内湍流发育的近地表层,运动方式以蠕移为主,沙丘表面湍流的主导作用使其输沙量随高度的变化满足负幂律关系,但中沙和细沙则以跃移运动为主,跃移沙粒输沙量的垂向分布呈现指数递减特征。
Based on the field observations of wind and sand flow in the sand dune of Changli Gold Coast, Hebei Province, and the numerical simulation of indoor wind tunnel simulation data, the vertical distribution patterns of sediment load of different particle size sandstorm flows in sand dunes of typical coastal areas in China were discussed. The results show that the vertical distribution characteristics of sediment load of sand grains with different grain sizes in the sand dune surface of Changli Gold Coast, Hebei Province are not consistent. The fine sand and medium sand meet the typical exponential decay distribution law, but the coarse sand is negative power Function distribution. The reason is mainly related to the distribution height of sediment carrying capacity and the differences in the mode of movement of sand particles with different grain sizes. On the actual non-uniform sand bed, the coarse sand mainly concentrated in the surface layer 4cm height turbulence near surface layer, the movement of creep-based, the leading role of surface dune turbulence so that the sediment discharge changes with height The law of negative power law is satisfied, while the middle sand and the fine sand are dominated by the leaping movement. The vertical distribution of the sediment discharge of the leaping sand exhibits exponential declining characteristics.