A two-species model of aeolian sand transport
A two-species model of aeolian sand transport
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DOI：
10.1017/s0022112004009073
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发表时间：
2004-07-10
影响因子：
3.7
通讯作者：
Andreotti, B
中科院分区：
文献类型：
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作者：
Andreotti, B
风输送沙子是由于水流所拖曳的颗粒的侵蚀与由此导致的风速减慢之间的平衡而产生的。从理论上研究了控制砂通量饱和的动力学机制。我们首先证明，以前的模型基于所有颗粒都具有相同轨迹的假设，要么不自洽，要么导致解不稳定。导出了基于离散状态数的模型，解决了这些问题。出现了两种明确的颗粒种类，分别对应于索尔顿（高能颗粒）和雷普顿（由于索尔顿的撞击而从沙床中喷出的颗粒）。它们发挥着特定的作用：风传输的负反馈仅限于蠕动层，而大部分传输是由于跃移造成的。受益于这两种物质的存在，模型得到了进一步简化，并且导出了阈值速度、饱和通量、气动粗糙度和饱和长度的依赖性，并与实验测量值进行了比较。
The transport of sand by wind results from the equilibrium between the erosion of grains dragged by the flow and the resulting slow down of the wind velocity. The dynamical mechanisms governing the saturation of the sand flux are investigated theoretically. We first demonstrate that previous models, based on the assumption that all the grains have the same trajectory, are either not self-consistent or lead to unstable solutions. A model based on a discrete number of states is derived, which solves these problems. Two well-defined species of grain appear, which correspond to saltons (high-energy grains) and reptons (grains ejected from the sand bed by the impact of saltons). They play specific roles: the negative feedback of the transport on the wind is limited to the reptation layer while most of the transport is due to saltation. The model is further simplified, benefiting from the existence of these two species and the dependencies of the threshold velocity, the saturated flux, the aerodynamic roughness and the saturation length are derived and compared to experimental measurements.