复膜沙袋阻沙体与芦苇高立式方格沙障防沙机理风洞模拟实验

模型按1:10比例尺设计,在u_∞=7.0 m·s^-1、u_∞=10.0 m·s^-1和u_∞=15.0 m·s^-1实验风速下,先在纯气流作用下测定流场结构,然后在风沙流作用下测定蚀积状况。实验结果表明:紧密型、疏透型和通风型3种不同结构的复膜沙袋阻沙体前近处分布有拐角阻滞绕流区、阻沙体顶下方抬升加速区、阻沙体后回流区、阻沙体后贴地层低速回流区等流场特征结构,紧密型、疏透型两种类型复膜沙袋阻沙体防风阻沙效果显著;2.5 m×2.5 m、5 m×5 m和10 m×10 m的高立式芦苇方格前沿流速逐渐增大,最大值出现于迎风第一格上空,而后逐渐阻滞减速,至15~20 m处趋于稳定,区内积沙均匀。复膜沙袋阻沙体与原状芦苇高立式方格沙障适宜于流动性沙漠地区各种设施的沙害防治工程。

Wind Tunnel Test on Sand-preventing Mechanism of Double-filmed Sand-bag Obstacle and Upright Checkerboard Sand-barrier

The model was designed with 1:10 scale,and the testing wind velocity consist of 7.0 m·s^-1,10 m·s^-1and 15.0 m·s^-1.The structure of flow field was measured under wind only,then,the erosion deposition features were measured under sand-carrying wind flow.The results are as follows:(1) Near the 3 types obstacles of tight,sparse and air,there are some structural characteristics of retardant periptery before the body,lifting accelerating area just pass the top,back-flow area behind the body,and low-speed back-flow area on the surface behind the body.The tight and sparse sand bag obstacles have obvious sand-preventing effect.(2) The rulers of upright checkerboard sand barriers include 2.5 m×2.5 m,5 m×5 m,10 m×10 m.The sand-carrying wind speeds up gradually when it flows to the objects,and reachs the maximun over the first checkerboard;then,the speed decreases gradually resulted from the stopping function of the objects;the flow trends stable after 15~20 m course,and sands deposite evenly.The test proved that the double filmed sand bag obstacle and initial upright checkerboard sand barrier are effective for protecting all the facilities in sand-shifting desert areas.