风沙两相流活动精细化观测与模拟研究

In north west China, where the climate is dry and deserts are prevalent, so it is one of main origins of sandstorms. Sand movement has produced great harm to the economy and ecological environment of local and its downstream region. The project takes the Taklimakan desert as study area, to develop meticulous observation experiment on wind-blown-sand two phase flow in field based on high frequency of sand collectors, piezoelectric sensor of wind erosion, BSNE gradien sand collectors, the adaptive detector of wind velocity, temperature, humidity profiles, eddy covariance system. Then, combining with numerical simulation, to observe the wind profile, wind speed fluctuation, vertical profiles of sand-mass flux, sand transport, vertical distribution of sand particle motion and particle size, analyze the otherness of wind sand flow structure and its forming mechanism under different sampling frequency and observation network. To simulate the wind-sand field, structure of wind-sand flow, sediment-carrying wind speed and height of sand saltation etc on different wind speeds and different sand source supplied conditions. Improvement the key parameters in the numerical, test and enhance the simulated result. And offer basic support for researching sand drift activity and desertification.

我国西北地区气候干燥，沙漠广布，是重要的沙尘源区。风沙活动与沙漠化对当地及下游地区的社会经济、生态环境造成巨大破坏。项目选择塔克拉玛干沙漠作为研究区，利用高频率全自动集沙仪，压电式风蚀传感器，BSNE梯度集沙仪，近地表风、温、湿梯度探测仪，涡动相关探测仪等探测仪器，开展野外条件下风沙两相流运动的精细化观测，结合数值模拟，观测风沙两相流运动过程中风速廓线、风速脉动、输沙量垂线分布、输沙率、沙粒运动及沙粒粒径的垂向分布；分析和探讨不同采样频率及不同观测布局条件下，风沙流结构特征的差异性及形成机制；模拟不同风速及沙源供给条件下，风沙流场、风沙流结构、挟沙风速及沙粒的跃移高度等；改进数值方程中的关键参数，验证并提高模拟效果，为研究风沙活动及沙漠化提供基础支撑。

我国西北地区气候干燥，沙漠广布，是重要的沙尘源区。风沙活动与沙漠化对当地及下游地区的社会经济、生态环境造成巨大破坏。项目选择塔克拉玛干沙漠作为研究区，利用高频率全自动集沙仪，压电式风蚀传感器，BSNE梯度集沙仪，近地表风、温、湿梯度探测仪，涡动相关探测仪等探测仪器，开展野外条件下风沙两相流运动的精细化观测。探索了野外条件下风沙两相流活动精细化观测试验的方法与数据集成技术，检验了现有监测仪器及方法的适用性，改进了风沙两相流野外试验方法；获取了贴地层（2m以内）、近地层（80m以内）沙尘天气过程的风速廓线、风速脉动、输沙量垂线分布、沙粒粒径垂线分布及输沙率的空间差异性等风沙流结构特性参数；评估了原有风沙两相流活动数值模拟方案对塔克拉玛干沙漠的风沙流结构的模拟效果，然后利用实测的摩阻风速、沙粒粒径等参数，对风沙两相流活动数值模拟方案进行了本地化改进，使得模型能够较好的模拟塔克拉玛干沙漠的风沙流结构，研究结果为研究风沙活动及沙漠化提供基础支撑。