Effect of tether sag on vortex-induced vibration of tether in submerged floating tunnels

To study the effect of tether sag on vortex-induced vibration of tether in submerged floating tunnels, the nonlinear vortex-induced vibration equation of submerged floating tunnel tether is set up whether the sag effect is considered or not. Subsequently, an approximate numerical solution of planning submerged floating tunnel tether is obtained by applying Galerkin method and Runge-kutta method. Effect of tether sag on mid-span displacement and axial force of tether is analyzed when the vortex-induced resonance and parametric resonance takes place. The results show that, mid-span displacement and axial force of tether increases dramatically when the vortex induced resonance and parametric resonance takes place; the tether sag results in the asymmetry of tether vibration amplitude; taking sag effect into account makes the mid-span displacement and axial force of tether larger; tether sag makes the parametric vibration of tether be induced in a shorter time.