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基于地形和流场实测,研究了包兰铁路沙坡头段铁路防护体系近地面流场沿NNW—SSE方向的变化.结果表明,由于地形变化以及人工植被和草方格的存在,防护带内等风速线沿风向呈逐渐变疏和抬高的趋势,各高度的风速总体上呈递减趋势,风速放大率为负;沙丘迎风坡风速放大率为正,流动沙丘迎风坡风速放大率高于固定沙丘迎风坡.沙丘背风坡2.5m高度内风速放大率总体为负.防护带内的固定沙丘背风坡气流通体减速,各高度的风速放大率全部为负,平均为-1.48%/m.防护带内地表空气动力学特征发生变化,其中沙丘迎风坡地表风速廓线接近于对数率;人工植被带地表空气动力学粗糙度显著高于流沙区.
Based on the topographic and flow field measurements, the changes of the NNW-SSE flow field near the Baotou-Shabaoshui rail protection system were studied. The results show that due to the change of topography and the presence of artificial vegetation and grass checkered, The wind speed at all altitudes showed a decreasing trend as a whole, and the wind speed magnification was negative. The wind speed magnification of windward slope on the sand dune was positive, and the wind speed magnification of the windward slope on the moving sand dune was higher than that of the fixed Sand dune windward slope.The magnification of wind speed 2.5 m in the leeward slope of sand dune was negative in general.The gas flow in the leeward slope of the fixed sand dune in the guard band slowed down and the wind speed magnification at all altitudes was all negative with an average of -1.48% The surface aerodynamic characteristics of the inland belt changed. The surface wind velocity profile of the windward slope on the dune was close to the logarithmic ratio. The surface aerodynamic roughness of the artificial vegetation zone was significantly higher than that of the quicksand area.