定日镜的风压分布与脉动特性

Distribution and fluctuation characteristics of wind pressure on heliostat

定日镜结构的形体特殊，不同于普通的建筑结构。采用表面测压技术对定日镜模型进行了三维风荷载风洞试验，得到了各测点风向角0°～180°范围内，竖向角为0°～90°情况下，镜面平均风压和脉动风压的分布，重点探讨了镜面脉动风压特性。研究结果表明脉动风荷载功率谱变化受湍流风速和旋涡脱落的影响，并与斯托哈罗数有关；镜面正反两侧脉动风压主要呈正相关特性，在顺风向情况下相关系数较小，横风向情况下相关系数较大；风向角及竖向转角较小时，脉动风压更好地符合高斯分布。

Structure of heliostat is unusual and different from common ones. A 3D wind load test of heliostat in wind tunnel was carried out using surface pressure measuring technology and the distribution of mean wind pressure and fluctuating wind pressure at measured points of mirror＇s surface was obtained while wind direction angle varied from 0° to 180° and elevation angle varied from 0° to 90°. The results show that the wind load power spectrum changes with longitudinal wind turbulence ＆ vortex and is related with Strouhal number; the fluctuating wind pressures at face and back show positive correlation mainly and the correlation coefficients in case of longitudinal wind direction are less than those in case of lateral direction; the fluctuating wind pressures preferably meet Gaussian distribution for smaller elevation angle ＆ wind direction angle.