大缩尺比气弹模型风洞试验紊流积分尺度修正

风洞试验气弹模型缩尺比常选为1/300~1/800以满足紊流积分尺度相似要求，但一些复杂结构气弹模型实际缩尺比为1/40~1/100以减少模型加工难度及提高模型精度。这类大几何缩尺比造成紊流积分尺度的相似性严重偏离，必须对紊流积分尺度不相似时的风洞试验结果偏差进行修正。基于随机振动理论，推导了考虑1阶基本振型的顺风向风振响应及风振系数计算表达式。通过对一格构式输电塔风振响应分析，研究了顺风向紊流积分尺度Lxu对该结构风振响应的影响。研究结果表明：紊流积分尺度对结构抖振响应有显著影响，对峰值响应及风振系数影响也较大。对于该塔1/40大缩尺气弹模型风洞试验，由紊流积分尺度不相似带来的风振系数试验值的最大偏差可达27%，风振系数平均偏差也接近14%，试验结果偏保守。为便于应用，建议了较为通用的、由紊流积分尺度不相似引起的修正系数，这一修正系数随着结构阻尼比、结构频率与风谱卓越频率的比值（频率比）的增加而减小。

Turbulence integral scale corrections to aeroelastic wind tunnel experimental results with large scale model

The aeroelastic model scale of target structure in wind tunnel test should be commonly selected as 1/300-1/800 to match the turbulence integral scale similarity. On the other hand, the practical model scales for complicated structures may be within 1/40-1/100 to reduce the difficulty in model fabrication and to improve the model accuracy. The large values of model scales lead to severe distortion of the turbulence integral scale similarity, and corrections must be made to wind tunnel testing results to compensate the mismatch in turbulence integral scales. Based on random vibration theory, the along-wind buffeting response considering only the fundamental mode of a structure was presented and the formulae for gust loading factors were obtained. With the formulae, the effect of turbulence integral scale on gust loading factors of a high-rise transmission line tower was studied. An appreciable effect is identified and the maximum and average difference in gust loading factors may reach nearly 27% and 14%, respectively, for the 1/40 aeroelastic model of the studied tower. As a first generalization, a set of more general correction factors also applicable to other structures other than the transmission line towers are finally developed for correction purpose, and correction factors decrease with the increase of modal damping ratio, and the ratio of structural frequency to predominant frequency in wind spectrum.