千米高度偏转风场风洞模拟技术研究

To investigate the effect of the twisted wind flow on the wind effects of megatall buildings, a modified passive simulation technology, i.e., a combination of a self-developed vane system and the traditional passive simulation devices, is developed to simulate the twisted wind flow with a length scale of 1:1 000. The mean wind speed and wind direction profiles determine by the field measurement, and the turbulence intensity profiles stipulated in the Chinese Load Code are determined to be the target wind characteristics for the thousand-meter high twisted wind flow. Then the effects of different devices on the twisted wind flow characteristics are analyzed in detail. Results show that the mean wind speed profile for the simulated twisted wind flow followed the power law with an exponent of 0.09, and the mean wind direction profile agrees well with the Ekman spiral with a maximum error of 1.5°. The simulated turbulence intensity profile fluctuate within those of the exposure categories C and D in Chinese Load Code, indicating the reasonability of the results. A good consistent wind property is obtained in an area of 2.5×1.5 m² around the center of the turntable with a range of -0.5 - 2 m in the streamwise direction and -0.75 - 0.75 m in the span wise direction. Thus, the simulated twisted wind flow can provide a solid basis for the further study of the characteristics of wind loads and wind-induced responses for thousand-meter high mega tall buildings, as well as systematic evaluation of the effects of twisted wind flow.