Numerical Simulation Of Vortex-Induced Vibration Of Cylindrical Structures Based On Different Dimensional Models

Vortex-induced vibration is an important problem in windinduced vibration of structures,and it often occurs at low wind speeds.There are hidden dangers of vortex-induced vibration in the main beam sections,bridge cables,suspenders of many large-span bridges and highrise buildings;In addition,the continuous periodic large vibration in the "locked interval" will cause problems such as joint fatigue failure of the structure,thereby reducing the safety and durability of the structure.Therefore,it is very necessary to carry out the relevant research on the vortex-induced vibration problem.This thesis is based on the fluid dynamics analysis software Fluent,and independently wrote a parallel UDF interface program that can realize the functions of extracting the fluid force on the structure,solving the structure vibration response and feedback of the structure response required in the two-way fluid-structure interaction calculation.Twodimensional and three-dimensional numerical models are established respectively to study the vortex-induced vibration problem based on rigid body structure and flexible body structure.(1)In the two-dimensional simulation based on the rigid body structure,the vortex-induced vibration calculation of the cylindrical structure under the model of different flow degrees of freedom is completed with the number of flow degrees of freedom the structure has as a variable.And the vortex-induced vibration characteristics of the structure are analyzed in detail from the aspects of lift coefficient,drag coefficient,dimensionless amplitude,vortex shedding frequency and wake characteristics.Finally,the vortex-induced vibration characteristics of the models with different number of degrees of freedom under a series of mass ratios are compared and analyzed,and the applicable mass ratio interval of the models with different number of degrees of freedom of flow direction is discussed.(2)In the three-dimensional based on the structural form of the flexible body,the "locking" phenomenon of the vortex-induced vibration of the first two modes of the flexible cylinder was successfully captured,and it was found that the vortex-induced vibration problem of the higherorder mode could not be ignored.The vortex-induced vibration characteristics of the flexible cylinder are analyzed in detail from the dimensionless amplitude,the axial spatial distribution of the vortexinduced force,and the characteristics of the wake in space.Finally,the influence of damping parameters on the vortex-induced vibration of the flexible cylinder is analyzed.(3)In the vortex-induced vibration control analysis of a flexible cylinder,a tuned mass damper is applied.The influence of parameter changes on the vibration suppression effect is analyzed from the aspects of installation position,damping parameters,quality parameters,frequency parameters,and TMD quantity.