[目的]猫头刺盾状移动式固沙障是运用仿生学原理,由盾状铁网筛与上方扎制固沙灌木猫头刺(Oxytropis aciphylla)茎叶构成的一种新型固沙障.对猫头刺盾状移动式固沙障的防风固沙效应进行试验,以确定最佳固沙障类型,并揭示其防风固沙机理,为野外工程防沙措施的选择和制定提供理论依据.[方法]通过风洞模拟试验,在6,10,14,18 m/s 4个风速条件下测量了猫头刺盾状移动式固沙障的风速流场,并在10,14,18 m/s 3个风速条件下对该固沙障进行了携沙风吹蚀试验.对照分析了原位自然型与不同类型,不同大小仿生猫头刺盾状移动式固沙障的防风沙效应.[结果]①气流在经过猫头刺盾状移动式固沙障时速度均会减弱,形成明显的减速区.在6 m/s时,减速沉降区均达到了 20 H(H为沙障高度,H=11 cm);随着风速增加,减速沉降区缩小.风速10与14 m/s时,减速沉降区为15 H;且在风速18 m/s时,也能维持15 H的减速沉降区.②3种风速梯度下,猫头刺盾状移动式固沙障的平均输沙量是无沙障的13.8％(10 m/s风速),21.1％(14 m/s风速),23.4％(18 m/s风速).[结论]结构完整,直径更大的猫头刺盾状移动式固沙障具有最好的防风沙效果.该移动式仿生固沙障防风沙效果好,可移动,可组合并可机械化编制,在防治荒漠化、防风固沙领域有广阔的应用前景.
Wind Tunnel Simulation Experimental Study on Sand Fixation Effects of Shield-shaped Movable Sand Barriers Made with Oxytropis Aciphylla
[Objective]The shield-shaped movable sand barrier is a new type of sand fixation barrier.The barrier is made according to bionic principles and composed of a shield-shaped iron mesh screen supporting the stems and leaves of the sand fixation shrub,Oxytropis aciphylla.The sand fixation effects of shield-shaped movable sand barriers were determined to choose the optimized type of sand fixation barrier to reveal the wind break and sand fixation mechanisms of shield sand barriers,in order to provide theoretical references for the selection and formulation of sand control measures in field projects.[Methods]A wind tunnel simulation experiment was conducted.The wind speed and flow field of the shield-shaped sand fixation barrier were measured at four wind speeds of 6,10,14,and 18 m/s.The wind erosion experiments were conducted on the sand fixation barriers at three wind speeds of 10,14,and 18 m/s.Comparative analysis was conducted on the windbreak and sand fixation effects of in-situ natural and different size bionic barriers.[Results]① When the airflow passed through the shield-shaped movable sand fixation barrier,its velocity weakened,forming a significant deceleration zone.At 6 m/s,the deceleration settlement zone reached 20 H(H means the height of barriers,H=11 cm).As wind speed increased,the deceleration settlement zone decreased.At 10 and 14 m/s wind speed,the deceleration settlement zone was 15 H.At 18 m/s wind speed,the barrier also maintained a deceleration settlement zone of 15 H.② Under the three wind speeds,the average sediment transport capacity of the new type of shield-shaped movable sand fixation barrier was 13.8％(10 m/s wind speed),21.1％(14 m/s wind speed),and 23.4％(18 m/s wind speed)of the sediment transport capacity without sand barriers.[Conclusion]The shield-shaped movable sand fixation barrier with a complete structure and a largest diameter had the best wind and sand prevention effect.The shield-shaped movable bionic sand fixation barrier had good wind and sand prevention effects,and can be moved,combined,and mechanically woven.It has a broad application potential in the field of desertification prevention,and wind and sand fixation.
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