基于大涡模拟的三维高层建筑结构气弹响应数值模拟

以宽高比为1∶6的方形截面高层建筑为研究对象，采用弱耦合分区交错算法，流体域采用大涡模拟方法，进行了紊流边界层风场内三维高层建筑结构多自由度模型的气弹数值模拟，计算中考虑了来流紊流，以及结构的顺、横风向响应。将结构静止时大涡模拟结果与刚性模型测压风洞试验进行比较，验证了该方法在准确预测结构风荷载方面的可行性。通过与气弹模型风洞试验结果的比较表明，本文数值分析方法可用于求解风与结构的相互作用，且具有较高的精度。进行了高折减风速下的气弹数值模拟，研究了结构顶部顺、横风向位移响应随折减风速的变化规律。结果表明：结构风振气弹响应主要为来流紊流引起的顺风向抖振和旋涡脱落引起的横风向涡激振动；折减风速较小时，结构顺、横风向位移振幅相当，且位移响应均相对较小；随着折减风速的增加，结构位移响应增大，横风向涡激振动逐渐占据主导地位，并经历了从“拍”到“涡激共振”的转化。

LES based numerical simulation of aeroelastic response of a 3D tall building

The aeroelastic response of a square section tall building with 1∶6 width to height aspect ratio in atmospheric boundary layer was numerically simulated, using loosely coupled method. In the present study, large eddy simulation technique was adopted with consideration of inflow turbulence. The wind-induced along and across vibration responses were both considered. The present method was verified to be able to accurately predict wind loads on buildings at rest, by comparing large eddy simulation results with rigid model wind tunnel experiment. The simulated wind-induced along and across vibration responses were compared with corresponding aeroelastic model wind tunnel experiments. The comparison results show that the present method is applicable to a certain extent in solving wind-structure-interaction problems. Aeroelastic responses of the building model under high reduced wind velocities were also investigated. Variation of the along-wind and across-wind displacement responses at different reduced wind velocities was analyzed in detail. The aeroelastic response of the building composes of two parts, i.e. the along-wind buffeting induced by inflow turbulence and the across-wind vortex-excited vibration. The along-wind and across-wind displacement responses were small with almost the same amplitude at low reduced wind velocities. With the increase of the reduced velocity, the displacement responses become large and the across-wind vortex-excited vibration becomes dominant, transferring from the beat-phenomena to the vortex-excited resonance.