Vortex Induced Vibration and Wind Flow Around Bridge Cables

摘要

In the paper two models are analyzed. First model is the wind flow around the ellipse cylinder that can correspond to the cable of the suspended and cable-stayed bridge. Computations are performed for subcritical regime from the range of Re= 6.5 × 10~4 to Re= 1.4 × 10~5. In the analyzed case, the RNG k-ε method, belonging to the Reynolds-Averaged Navier-Stokes models, is used. The numerical simulations are performed for aspect ratio from the range of B/D= 0.60 to B/D= 2.2. The analyzed ellipse cylinder reflects the possible change of the cable's section due to the ice. The behavior of lift coefficient in time domain is presented. The value of lift coefficient was calculated for the purpose of the analysis in the model of vortex induced vibrations. The spectra density analysis for lift force is presented and the velocity contour around ellipse cylinder is drawn. On the basis of the calculated lift coefficient from the first model, the vortex induced vibration model is formulated in second model. In the study the dimensionless amplitudes of motion A/D for different damping parameter η_c is presented. Also the phase angle between displacement y(t) and the force F(t) is shown. The dependence of dimensionless air velocity S_tv_r and response frequency {formula} is performed. The analysis of influence of Reynolds number on dimensionless displacement amplitude and aspect ratio on the r.m.s. lift coefficient are investigated.