考虑模型抖振力跨向不完全相关性效应的气动导纳识别

发布时间：2018-05-04 00:07

本文选题：气动导纳识别 + 自谱-交叉谱综合最小二乘法　；参考：《实验流体力学》2014年05期

【摘要】：首先通过考虑节段模型上抖振力跨向不完全相关性效应推导了节段模型风洞试验中作用在模型断面上的分布抖振力谱和由底支式天平测到的模型总抖振力谱之间的关系。然后,以准平板断面为例,进行了格栅湍流场节段模型的测力和同步测压试验,获得了模型总抖振力谱以及模型抖振力跨向相关性函数。接着,采用等效导纳法以及抖振力自谱和抖振力脉动风速交叉谱综合残量最小二乘法分别识别了准平板节段模型等效气动导纳和六分量气动导纳,讨论了模型抖振力跨向不完全相关性效应对气动导纳识别结果的影响,并把识别得到的准平板断面气动导纳与平板断面气动导纳的理论结果——Sears函数进行了比较。结果表明:忽略抖振力跨向不完全相关性效应(即假设节段模型分布抖振力沿跨向完全相关)而直接采用平均抖振力作为断面上分布抖振力的传统方法会导致气动导纳识别结果偏小,并且,其偏小程度会随着频率的增加而增加;此外,相对于抖振升力和扭矩相关的气动导纳分量而言,由于抖振阻力的跨向相关性比抖振升力和扭矩的跨向相关性显得更弱,因此抖振力跨向不完全相关性效应对阻力相关气动导纳分量识别结果的影响更大;利用识别得到的六分量气动导纳反算的作用在模型上的分布抖振力谱与试验中实测结果非常接近,经抖振力跨向不完全相关性效应修正后的竖向脉动风速对应的升力和扭矩气动导纳分量的识别结果与Sears函数也比较接近,从而验证了用于六分量气动导纳识别的自谱-交叉谱综合最小二乘法的可靠性。
[Abstract]:The relationship between the distribution of buffeting force spectrum acting on the model section in wind tunnel test and the total buffeting force spectrum of the model measured by the bottom support balance is derived by considering the cross-directional incomplete correlation effect of buffeting force on the segmental model. Then, taking the quasi-flat section as an example, the force measurement and simultaneous pressure measurement of the grid turbulent segment model are carried out, and the total buffeting force spectrum and the cross-direction correlation function of the model buffeting force are obtained. Then, the equivalent admittance and six-component aerodynamic admittance are identified by using the equivalent admittance method and the residual least square method of the buffeting force self-spectrum and the cross-spectrum of buffeting force pulsating wind speed, respectively. The effect of model buffeting force on aerodynamic admittance identification is discussed, and the theoretical results of quasi-plate section aerodynamic admittance are compared with those obtained by Sears function. The results show that the traditional method of adopting the average buffeting force as the distributed buffeting force on the cross section directly neglects the incomplete correlation effect of buffeting force across the cross-section (that is, assuming that the buffeting force is completely correlated along the span direction of the segmental model) and can lead to gas. The result of dynamic admittance recognition is small, In addition, compared with the aerodynamic admittance components related to buffeting lift and torque, the cross-direction correlation of buffeting resistance is weaker than that of buffeting lift and torque. Therefore, the cross-direction incomplete correlation effect of buffeting force has a greater effect on the identification results of drag dependent aerodynamic admittance components. The buffeting force spectrum on the model is very close to the experimental results. The identification results of lift and torque components corresponding to the vertical pulsating wind speed modified by the incomplete correlation effect of buffeting force are similar to the Sears function. Thus, the reliability of the synthetic least square method for six component aerodynamic admittance identification is verified.
【作者单位】：同济大学土木工程防灾国家重点实验室;同济大学桥梁工程系;汕头大学风洞实验室;同济大学桥梁结构抗风技术交通行业重点实验室;
【基金】：科技部国家重点实验室基础研究资助项目(SLDRCE08-A-02) 桥梁结构抗风技术交通行业重点实验室开放课题(KLWRTBMC12-01) 国家自然科学基金重大研究计划集成项目(91215302)
【分类号】：U441.3

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