Andreja Werner

Numerical model of towing line in sea transport

Towing as a specific type of sea transport is often used for installing objects for drilling and exploitation of underwater gas and oil wells. Also, towing proved to be a cost-effective solution for the installation of the offshore wind turbine electric generators at sea locations. Because of the mass of these objects the need for towing increases progressively. Time domain numerical model for the wave-induced motions of a towed ship and the towline tension in regular head seas is presented in this paper. For the sake of simplicity, one end of the towing line is attached to ship’s bow and another end has prescribed straight line motion. All considerations are done in the vertical plane so the ship is modeled as a rigid body with three degrees of freedom. Hydrodynamic loadings due to waves are taken into account along with added mass and damping. Dynamics of the towing line is described by finite elements. Due to the nonlinear properties of the problem calculations are done in time domain. Comparison of the obtained numerical results is made with previously published results.Copyright