不均匀沙起动理论及戈壁风蚀层形成动力学

Threshold Velocity for Mix-sized Sand and Formation Dynamics of Gravel Surface

定义了不均匀沙有别于均匀沙的起动概念,得出了不均匀沙中各粒径沙具有不同的流体起动风速,且不等于对应粒径均匀沙流体起动风速的结论,具体表现为:不均匀沙中小粒径沙的流体起动风速大于相同粒径均匀沙的流体起动风速,而其中大粒径沙的流体起动风速又小于相同粒径均匀沙的流体起动风速。然后应用不均匀沙起动风速理论,讨论了戈壁风蚀层与环境风力之间动态平衡的建立过程。

Based on analyzing the initiation process of mix-sized sand by wind, a theory for the wind threshold of mix-sized sand is presented, which reveals that the threshold velocity of a large diameter in mix-sized sand is less than the threshold velocity of single-size sand having the same diameter, but the case to a small diameter in mix-sized sand is just converse. Then, using the threshold theory of mix-sized sand, we depict the formation of a gravel surface and the dynamical stabilization between turbulent wind and gravel surface.