RESEARCH ON DYNAMIC RESPONSE OF SUBMERGED FLOATING TUNNEL TO REGULAR WAVE FORCES

The dynamic response of a submerged floating tunnel due to regular wave forces is investigated. The equations of motion and boundary conditions are derived using Hamiltonian variation principle. The dynamic model of the submerged floating tunnel is presented, considering nonlinear coupling between the axial and transverse vibrations of the tether. The nonlinear coupled partial differential equations are solved numerically using the finite difference approach. The wave forces on the tunnel tube and the tether are calculated using Airy’s linear wave theory and Morison’s equation. The simulated results show that if the length of the tether is long enough so that its frequency of self-vibration is in the range of the wave frequency, self-vibration modes of the tether are excited. And the coupling effect between axial and transversal vibrations of the tether can not be discarded. As the wave height or the specific ratio of the tunnel increases, the surge and sway responses increase too, but the heave response and the stress in the tether are hardly affected by the wave height.