大跨度桥梁气动稳定性数值计算模型与方法

Computational models and methods for the aerodynamic stability of long-span bridges

大跨度桥梁气动稳定性研究目前主要采用直接风洞试验法和基于风洞试验识别参数的理论分析法。随着计算流体动力学和计算机硬件设备的不断发展,后者方法中的气动参数识别有可能用数值计算代替风洞试验,因此可望建立起一种大跨度桥梁颤振研究的纯理论计算方法。主要从自激气动力模型、颤振导数数值识别、二维与三维颤振分析方法3个方面简要介绍大跨度桥梁空气动力稳定性计算原理和方法,并通过对理想平板断面及其悬臂结构、H形截面及其上海南浦大桥、闭口箱梁及其瑞典Ho!gaKusten桥的数值分析,总结和归纳现有数值计算原理和方法的主要问题及发展展望。

The evaluation of bridge aerodynamic instability is traditionally based on direct wind tunnel test and theoretical analysis with experimentally identified parameters from wind tunnel test. With the developments of computer technology and computational fluid dynamics, theoretical method is expected to be developed to replace wind tunnel test by numerically analyzing the aerodynamic flutter of long-span bridges. This paper introduces the models and methods for computationally determining the aerodynamic instability of long-span bridges, with emphasis on three aspects, including self-excited aerodynamic force model, numerical identification of flutter derivatives, and two- dimensional or three-dimensional flutter analysis method. Through a series of analyses of the thin-plate cross section and its cantilevered structure, the H-shaped section of the Nanpu cable-stayed bridge, and the closed box section of the Hoga Kusten Bridge, the main problems and the key prospects of CFD techniques are concluded.