高立式格状沙障防风效益

针对在风沙危害严重地区,半隐蔽式格状沙障容易遭沙埋,且其防护年限短等问题,提出了一种新型的防沙措施——高立式格状沙障(高1m,长×宽=8m×8m),并对该沙障的防风效益进行了观测。结果表明:(1)高立式格状沙障对风速具有显著削弱作用;且越接近地表,风速被削弱的程度越大;沙障内5个观测点2m高处风速平均减弱了33.0%,而0.2m高处风速平均减弱了81.5%。(2)高立式格状沙障使沙障顶部高度(1m)以下的风速廓线偏离对数曲线;沙障顶部以上风速和高度继续呈对数关系,且风速梯度明显大于对照点。(3)高立式格状沙障使地表粗糙度增大了44倍。

Windproof Efficiency of Upright Checkerboard Sand-barriers

Semi-buried checkerboard sand-barriers were easy to be buried by sand and had short windproff duration. A novel sand prevention measure-upright checkerboard sand-barrier which was 1 m in height, 8 m in length and width was introduced, and its windproof efficiency was investigated. The results were as follows:(1) The barrier significantly reduced the incoming wind velocity, and the effect became more intensive approaching land surface. The averaged wind speed from five monitoring sites within the barrier showed a 33.0% reduction at 2 m high and 81.5% at 0.2 m high.(2) Wind velocity profiles within the barrier deviated from logarithmic curve below the height of the upright checkerboard sand-barrier(1 m). Above the barrier height, wind velocity profiles still followed the logarithm law, and wind velocity gradient was higher.(3) The average land surface roughness within the barrier region increased 44 times compared to the control point.