Calculating The Flutter Critical Wind Speed By Free Coupled Vibration Method Based On CFD

By CFD numerical simulation method,researching the long-span bridge flutter stability has become an economic and effective means.As can be directly compared with wind tunnel experiments at each stage,this topic put forward a kind of freedom coupling vibration based on CFD method to calculate bridge flutter critical wind speed.To proving this kind of method,the works are as following:Firstly,this paper briefly introduces the three current research methods of bridge flutter,and points out the necessity of free vibration coupling method;To lay a solid theoretical basis for this topic,summarize the classical theory of bridge flutter;This paper briefly introduces the basic theory of CFD,meshing and parameter setting,etc.Then,to test and improve the freedom coupling vibration based on CFD method,take the ideal thin plate for comparison.At the same time put forward three different solutions to optimize UDF document.So the Newmark equation parameters can make the fluid-structure coupling effect more suitable for this topic.After comparing eight flutter derivatives,the freedom coupling vibration method in the main flutter derivative and part of the secondary flutter derivatives recognition performs well.Finally,combining with the Qipanzhou bridge wind tunnel experimental results,investigate the performance of freedom coupling vibration method in practical engineering.The flutter critical wind speed of the original plan and exert guide plate plan of Qipanzhou bridge and the flutter critical wind speed of CFD free coupled vibration method differ from1.42% to 9.90%,so the method is perfect.So as to explore the applicability of the method of coupling vibration,flutter fast identification method is proposed,and also discussed long-span suspension bridge torsion-vertical frequency ratio on the flutter critical wind speed.