Research On Across-wind Vibrations Of High-rise Structures With Circular Section

Across-wind vibrations of high-rise structures with circular section is much more complex than along-wind ones. Studies on the excitation mechanism have attracted extensive attention by many researchers of home and broad. Now this subject still remains one of the classical problems of bluff body aeroelasticity, particularly with respect to vortex-induced vibrations. At present it is difficult to achieve high Reynolds number associated with full-scale structures in wind tunnel testing, and due to aerodynamically coupling action of wind and structures, complicated aeroelastic phenomena are caused when across-wind vibrations occur, and etc. Because of above-mentioned reasons, till now rational and widely-used calculation method of across-wind vibrations have not been proposed in wind engineering, and the research is still on the exploratory stage. To provide further theoretical basis for engineering practice, certain exploration and development have been done on those aspects such as vortex-induced models, flow parameters associated with Reynolds number, vortex-induced resonance calculation of tapered structures and across-wind resonance of high mode, and some important conclusions are drawn.Firstly, the importance of this subject is pointed out and the present research states are simply reviewed. Then vortex-induced models which are now widely used are analysed and compared, and also they are discussed after combined with continuous bar model of structure movement. In the subsequent chapters a modified rms lift coefficient of cylinders' across-wind response is achieved which is independent of Reynolds number regime, and a simplified formula on maximum across-wind response of tapered high-rise structures with circular section is derived. In the fifth chapter a simplified check method for engineering application is proposed according to across-wind resonance of high mode. The across-wind response of the top mast in Wuhan International Security Building is calculated in the sixth chapter, and also its stength and stiffness under the wind loads are studied. At last, the primary conclusions are summarized and further research work is prospected.