中文摘要：

以空气动力学为理论基础,借助流体力学软件Fluent,对不同规格沙袋沙障近地表气流、风速廓线和防风效能等进行了模拟分析.结果表明：各监测断面风速廓线在距地表高度h≤0.5m时,变化差异较小;在h=0.5～2.0m高度范围内,风速呈递减趋势.近地表气流出现3个明显分区：加速上升区,低速下沉区和低速回流区,分别位于沙障防护工程的前上方、防护区上方和障格内.在低速回流区形成两个水平轴涡流,涡流中心流速最小.h=0.5m处成为沙袋沙障的风速分界点,h=0～0.5m时,沙障高度是风速主要影响因素;h=0.5～2.0m时,沙障规格是风速主要影响因素,2m×2m规格沙障效益显著.

英文摘要：

With the theoretical basis of aerodynamics,using fluid dynamics software （Fluent）,simulated examination has been performed to analyze near-surface air currents,wind speed profile and windbreak performance of sand-bag barrier with different sizes. The results show that,below the surface of 0.5m height,the changes of wind profile of monitored section are consistent,with little difference,but the wind speed decreases between 0.5～2.0m height. There are clearly three partitions of the near-surface air：accelerated upwards area,low-speed sink area and low-speed recirculation zone. They are located in front of the sand barrier protection projects,above the top of the protection zone and inside the barrier,respectively. In low-speed recirculation zone,there exist two horizontal axis eddy current and the velocity at eddy center is minimum. In addition,it can be seen that 0.5m height is a critical point to distinguish factors of affecting wind speed. In the range of 0～0.5m,the height of sand barrier is the main factor of wind speed,while in the range of 0.5～2.0m,the size of sand barrier is the main factor. Considering comprehensively the above factors,it is realized that the sand-bag barrier with 2m×2m size has the most remarkable protective effect.