Vortex-Induced Vibration Analysis Of Anchor Cables In Submerged Floating Tunnel

Submerged floating tunnel is also called the Archimedes bridge,was abbreviated to SFT.Submerged floating tunnel is an new form of cross-water transportatioin.Submerged floating tunnel has attracted wide attention from experts and scholars around the world to it after Hakkaart from Norway applied patent in 30 ages of last century.Restricted due to various reasons,the world is not a submerged floating tunnel was established,but a lot of research results has been fully proved that the structure in solving the problem of traffic across the waters,Marine conservation and reduce the project cost has great competitive power,but the technology also has many problems which need to be careful study and exploration.Just at this background,this paper selects the eddy excitation force analysis of submerged floating tunnel cable under the Marine environment as the research topic,in order to contribute to the advancement of submerged floating tunnel.The main research contents and research results are as follows:(1)Using the numerical simulation method,the rigid body module in ansys CFX and the shear pressure transmission(SST model)model are used to implement the cylindrical flow simulation.After validating the model,the model can be used to accurately complete the relevant numerical simulation.(2)Based on the qiandao lake suspension tunnel proposed by sino-italian cooperation,the vortex-induced vibration of the anchor cables of the suspension tunnel is analyzed in this paper.Through the study of the vortex-induced vibration analysis of anchor cable,when Ur?4,at this point in the initial branch of vortex-induced vibration,the lift coefficient curve and cross flow phase is consistent to the displacement time history curve,trailing vortex model for ‘2S',from the anchor cable cross flow displacement time history curve of can see significant "clap" phenomenon,and then to the displacement of cross flow after Fourier transform,can see two peaks;When 4<Ur?10,at this point in the branch of vortex-induced vibration,the lift coefficient curve and cross flow phase is no longer aligned to the displacement time history curve,a "mismatch" state,trailing vortex model by initial branch ‘2S' into ‘2P' mode(4<Ur?8)and ‘2T' model((9?Ur?10),anchor cable lateral displacement spectrum chart shows obvious characteristics of single peak.(3)The roughness will affect the vortex-induced vibration of anchor cable.The results show that as the surface roughness of the cylinder increases,the transverse flow non-dimensional displacement amplitude of the cylinder decreases first,and then increases when the roughness reaches a certain degree.The roughness will affect the locking interval of the cylinder.The cylinder with larger roughness has a larger locking interval,and the starting point of the locking is earlier and the ending point of the locking is later.(4)In the end,the effect of the mass ratio and the damping ratio of the cable vortex excitation is discussed,and the result shows that the lock interval of the vortex excitation vibration is affected by the quality ratio,the mass ratio is smaller,the larger the lock interval,and the cylinder is also more likely to have the vortex resonance phenomenon in the flow field.The value of the force coefficient is small,and the mean value of the force coefficient is in advance.In the vortex excitation vibration lock interval,the quality is more than the average of the resistance coefficient and the coefficient of lift coefficient.The average of the force coefficient,the mean value of the resistance coefficient,and the time of the cross flow to the infinite value of the random displacement are not changed by the change of the damping ratio.In the vortex excitation vibration interval,the corresponding coefficient of lift coefficient is large in the larger damping ratio,and the corresponding resistance coefficient mean,the horizontal flow to the infinite amplitude and the flow of the random displacement mean is smaller.The damping ratio mainly affects the posterior phase of the locking interval,and has little effect on the starting phase of the locking interval.