不同类型防沙堤流场的风洞实验模拟研究  

Wind Tunnel Simulation on Flow Fields around Different Types of Sand Dikes

作　　者：李建国[1] 屈建军[1] 李芳[1] 安志山[1] 韩庆杰[1] 牛清河[1] 李国帅[1] 谭立海[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所沙漠与沙漠化重点实验室/敦煌戈壁荒漠生态与环境研究站,甘肃兰州730000

出　　处：《中国沙漠》2012年第2期291-299,共9页Journal of Desert Research

基　　金：国家自然科学基金项目(40930741);中国科学院重要方向性创新项目(KZCX-YW-329);铁道部科技研究开发计划(2009G020-A)共同资助

摘　　要：防沙堤在风沙防护体系中发挥着重要的作用。对不同形状、不同倾角和不同高度防沙堤的流场结构进行风洞模拟实验,对不同类型防沙堤的防护效益进行评价。研究结果表明:①防沙堤强烈地影响了周围的气流流动特性,根据不同流场特征将其划分为5个典型区域:迎风坡脚低速区、遇阻抬升区、集流加速区、减速沉降区和消散恢复区,其中迎风坡脚低速区和背风侧减速沉降区能有效降低风速、阻滞风沙流。②梯形较三角形防沙堤形成的迎风坡脚低速区范围更大,而三角形较梯形防沙堤形成的有效防护距离更大。③三角形防沙堤的防护范围随风速的增大而减小。三角形防沙堤形成的有效防护距离随迎风坡倾角的增加而增大;迎风坡脚低速区范围随倾角增大而减小。④倾角40°的三角形防沙堤模型在各组风速下均形成最大的有效防护距离。⑤防沙堤背风侧的有效防护距离与沙堤高度呈正相关。Sand dike plays an important role in the sand-control system.In this paper,wind tunnel experiments were conducted to simulate the protective effect of a series of sand dike models with different shapes,dip angles and heights.Results showed that:①Sand dikes affected the flow characteristics significantly.Five typical sub-areas in flow field around sand dike could be identified based on their flow characteristics: low-speed area before windward slope toe,resistance-confronting lifting area on the windward flank,mass flow accelerating area above the top of the dike,flow-sinking decelerating area of leeward slope and dissipating recovering area.The low-speed area before the dike and the mass flow accelerating area above the top of the dike could reduce wind speed and prevent sand transport.②Considering the size of low-speed area before the dike body,the trapezoidal sand dike was better than the triangular one,but from the aspect of the effective shelter distance,the conclusion was just the opposite.③The protective effect of the triangular sand dike reduced with the growth of the wind speed.The effective shelter distance of the triangular dike increased with the growth of the dip angle,while the low-speed area before the dike body decreased with the growth of the dip angle.④The effective shelter distance of the triangular sand dike with a 40° dip angle was always the largest under four different wind velocities.⑤The effective shelter distance on the lee flank of the sand dike was correlated with the height of the sand dike.

关 键 词：防沙堤 风洞实验 流场结构 防护机理 有效防护距离 

分 类 号：X169[环境科学与工程—环境科学]