| The study of finite length cylindrical fluid-structure coupling vibration has important application value in offshore engineering,such as semi-submersible offshore platform.In recent years,more and more scholars at home and a broad have devoted themselves to studying the vibration characteristics of finite-length cylindrical fluid-structure coupling,and have begun to try to simplify the research of fluid-structure coupling by replacing the propeller with a rotating cylinder.The wake and free-end flow of a finite-length cylinder are quite complicated.Traditional experimental methods cannot meet the requirements of similar parameters and similar laws,and measurement and wake observation are more difficult.The rise of numerical simulation is imperative;The complexity of the parameters of the coupled analysis and the huge amount of calculation have also become a bottleneck affecting its development.Therefore,in order to have a more systematic study on the effects of various parameters on the flow around a finite length cylinder,and at the same time provide a basis for the feasibility study of a simplified model for the analysis of fluid-structure coupling of a rotating cylinder instead of a propeller,this paper has carried out a finite length cylindrical fluid-structure coupling analysis and experimental verification.In this paper,the numerical model and calculation method are first verified.Two numerical examples of the two-dimensional fluid-structure coupling analysis of the flow around the two-dimensional cylinder,the force and vorticity analysis of the three-dimensional infinitely long cylinder with fixed ends are used to verify the numerical method.reliability.Secondly,in order to study the influence of different working conditions on the lift resistance coefficient and wake field of the flow around the finite length cylinder,the method of combining CFD(Computational Fluid Dynamics)and experiment is used to fix the three-dimensional finite length cylinder with one end fixed and one end free.Numerical simulation and experimental verification of the flow under different length-diameter ratios and different Reynolds numbers were carried out.In the CFD part,through the verification of grid independence and the sele ction of the turbulence model,the three-dimensional finite-length cylinder under different working conditions was analyzed using the turbulence model combined with drag coefficient analysis and flow field visualization;The experimental equipment part used the self-designed four-post dynamometer and test bracket to complete the assembly,calibration and testing of the experimental equipment,and compared with the CFD results under the same working conditions.Subsequently,this paper further studies the in fluence of different structural materials on the deformation of the finite-length cylinder and the influence law on the lift resistance coefficient and wake field.The fluid-structure coupling calculation and experimental verification of the three-dimensional finite length cylinder with different structural field materials were carried out,and the force,deformation,vorticity field and velocity distribution were analyzed.Finally,on the basis of the above analysis,the propeller blades were replaced with cylinders to calculate the fluid-structure coupling of the rotating cylinder.The deformation and vibration characteristics of the rotating cylinder under different working conditions are analyzed,and the calculated wake field is compared with the literature.It is found that the trace of the rotating cylinder is highly similar to the trace of the propeller.Under certain circumstances The rotating cylinder can be used to replace the blade of the propeller for analysis,which can greatly reduce the worklo ad.Through the research in this paper,the influence of relevant parameters on the fluid-structure coupling of finite length cylinders under different working conditions is further enriched,which provides a richer data reference for the design of relevant offshore structures;Data support is provided for the feasibility of fluid-structure coupling analysis. |
