风沙蠕移运动研究

This project measures the average velocity of airflow and its turbulence intensity, creeping velocities of sand grains and creeping transport rate, and the flux of Aeolia sand flow of the flat sand surface and slope surface with different gradients of the Taklimakan Desert, Badain Jaran Desert, Tengger Desert, or coastal sandy land, slope and the flat sand surface using natural sands by field aeolian sand observation and wind tunnel experiment. This project elucidates the creeping condition of sand grains and their development process. This project develops the distribution function of creeping velocity of sand grains and the quantitative relationship between creeping velocity of sand grains and its corresponding creeping transport rate. This project constructs a new model of aeolian creeping transport rate. This project explore spatial variation law of aeolian creeping velocity of sand grains and their creeping transport rate. This project determines the contribute of creep sand grains to aeolian sand flow and its influence factors and reveals the variation mechanism of particle size of bed sands, creep sands and saltating sands. This project will have its contribution for complete of dynamics theory system of aeolian sand movements.

采用野外风沙观测和风洞模拟实验相结合，对塔克拉玛干沙漠、巴丹吉林沙漠、腾格里沙漠或者海岸沙地的平坦和坡面沙床面以及利用天然沙铺成的平坦沙床面等下垫面的不同位置，观测不同来流条件风沙流中气流平均速度和湍流强度、蠕移沙粒运动速度、蠕移输沙量以及风沙流输沙量等关键参数，研究蠕移沙粒运动条件和发展过程，发展蠕移沙粒运动速度分布函数及其对应的质量流量的定量关系，构建蠕移沙粒输沙量模型，弄清风沙输移过程中蠕移沙粒的贡献及其影响因素，揭示床面沙粒、蠕移沙粒以及跃移沙粒的变异机理，为完善风沙运动动力学理论体系做应有贡献。

采用野外风沙观测和风洞模拟实验相结合，对塔克拉玛干沙漠平坦沙地、地形起伏不大沙垄区平沙地、高大沙垄区平沙地以及不同地貌单元的新月形沙丘表面和防沙治沙工程体系内风沙蠕移进行了系统野外观测，利用塔克拉玛干沙漠、柴达木盆地沙漠、巴丹吉林沙漠、毛乌素沙漠以及呼伦贝尔沙地的天然风沙进行了不同床面长度、风速情形下风沙蠕移以及与之有关沙纹迁移、风沙输移等方面的详细风洞实验，分析风沙蠕移受力和起动机制及其影响因素，提出了利用一种面状激光传感器测定风沙蠕移输沙量的潜在方法，实验证实了“多陷阱方程组解析法”测定蠕移输沙量和“陷阱抛物线法”测定蠕移速度的野外适用性，发展了平坦床面不同风速、粒径、床面长度等多因素的统一模型，确定了平坦床面和沙丘表面蠕移速度的异同，发现不同地貌部位地表沉积物差异增加了风沙蠕移的复杂性，揭示了新月形沙丘表面风沙蠕移分布规律，阐明了风沙蠕移沿迎风坡的变化过程，探讨了与风沙蠕移有关的沙波纹、风沙输移、蠕移占比等风沙科学广泛关注的关键问题。