风观测对障碍物距离要求的定量评估

Quantitative Evaluation on Requirement of Obstacle Distance for Wind Observation

为定量评估气象站风观测对障碍物的距离要求,通过流体力学模式(Computational Fluid Dynamics,CFD)对单体建筑物进行了敏感性试验分析,并用河北沽源构筑物观测试验对模拟结果进行了验证。结果表明:(1)按照来流风速90%进行风速影响范围评估,障碍物对风速的影响距离为迎风面上3倍建筑物高度,背风面为28.5倍建筑物高度;按风向偏差10°进行风向影响范围评估时,障碍物对风向的影响距离为迎风面1.4倍建筑物高度,背风面为6.8倍建筑物高度,侧风向为2.8倍建筑物高度,垂直方向上为4倍建筑物高度。(2)对来流风速、建筑物厚度、建筑物高度、建筑物视宽角、来流风向的敏感性分析表明,10 m风速、风向测量对障碍物距高比的要求随背景风速的增大而增大;随着建筑物厚度的增大,10 m风速、风向观测对距高比的要求减小;当障碍物高度<6 m时,对10 m风速、风向观测影响不明显,当障碍物高度>6 m时,对距高比的要求随障碍物高度的增加而减小;随着建筑物视宽角的增大,10 m风速、风向观测对距高比的要求增大;来流风向与建筑物呈45°时,风速影响区域增大,风向影响区域水平方向增大、侧方向减小。

In order to evaluate the requirements of the obstacle distance from the anemometer,a set of numerical simulations and sensitivity experiments on an isolated building by Computational Fluid Dynamics( CFD) model were carried out with verifying by the field experiment at Guyuan,Hebei Province. The results indicate that:( 1) The range of 90% inflowspeed is 3 times the height of the building in windward side,and 28. 5 times of it in leeward side. M eanwhile,the range of 10 deviation to inflowwind direction is 1. 4 times the height of the building in windward side,6. 8 times of it in leeward side,2. 8 times of it in lateral side and 4 times of it in vertical height.( 2) By the sensitivity analysis of inflowspeeds,building thickness,building height,building angular width and inflowdirections,the requirements for the ratios of the distance to the height of building increase with the increment of the inflowspeeds,while that will be decreased with the increase of the thickness of the building. If the height of the obstacle belowthan 6 m,it seems not significantly to disturb the wind speed and direction at 10 m. If the height of the obstacles more than 6 m,the requirements of the ratios of the observed point distance to the height of the building will be reduced with the increase of the height of the building,and be enlarged with the increase of the building angular width. When the inflowcross over the building by 45°,the influenced scope of wind speed will be enlarged,as well as the horizontal affected area of wind direction,but the scope of lateral side for wind direction will be reduced.