新月形沙丘表面气流和风沙流结构变异

项目名称： 新月形沙丘表面气流和风沙流结构变异

项目编号： No.41271020

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 程宏

作者单位： 北京师范大学

项目金额： 80万元

中文摘要： 运用风沙地貌学、风沙物理学、多相流体力学等相关科学的理论与方法，以野外实地观测和风洞模拟实验相结合为研究手段，充分利用热膜风速仪、图像测速系统以及三维超声风向风速仪等现代高精密测试技术，测定新月形沙丘表面风沙流中气流平均速度和湍流度、沙粒运动速度以及输沙率等物理量，阐明沙丘表面不同部位气流场和沙尘物质垂向分布及其变化规律，建立沙丘形态、表面气流场和区域气流之间的定量关系，揭示沙丘背风侧次生气流的发生机制、强度及其对表面气流的影响。在此基础上，分析沙丘坡面上风速垂向变异情形下的沙粒受力和起动机制，研究沙丘表面不同部位沙粒运动过程，构建沙丘表面气流场与跃移层沙粒垂向浓度、沙粒粒径的定量关系，阐明沙丘表面风沙流结构变异机理，为新月形沙丘发育机理研究提供理论和数据支持。

中文关键词： 沙丘；风速；输沙量；沙粒粒径；形态参数

英文摘要： Based on relative theory and method of geomorphology of wind-drift sands, physics of Blown sand, multiphase fluid mechancis et al., this program measures plenty of mean velocities and turbulence of airflow and movement velocities of sand grains and flux of Aeolian sand flow around surface of Barchan dune by using portable anemoscope and sampler et al. observation instruments in field and 3D-PIV, hot film anemoscope and three dimensional ultrasonic wind instrumentet al. high precision measuring instruments in wind tunnel. First, this program illuminates airflow and vertical distribution of flux of Aeolian sand flow and their variation laws around surface of Barchan dune, and develops quantitative relationship among shape characteristics of Barchan dune, airflow of surface and regions airflow, and disclosure formation mechanics, intensity of second airflow in the leeward side of Barchan dune and the their influence on surface airflow based on relative theory and method of geomorphology of wind-drift sands, physics of Aeolian sand and multiphase fluid mechanic. Second, this program analyzes force process and liftoff mechanics of sand grains of surface of Barchan dune where there are vertical variance of wind velocities, and studies motion process of sand grains for different location around surface of Barchan dun

英文关键词： dune；wind velocity；aeolian flux；particle size of sands；morphology parameters