Dynamic modeling of an underwater moored platform equipped with a hydrokinetic energy turbine

The limited battery energy restricts the underwater operation duration of the underwater moored platforms. In this article, a horizontal axis ocean current turbine is conceptually designed to produce power for the underwater moored platforms and extend their operational durations. As part of the development of the horizontal axis ocean current turbine, a three-dimensional dynamic model of the system is proposed. The underwater moored platform is modeled as a rigid body with the Newton–Euler method and the cable is modeled with a lumped mass method. Motion simulations are then performed to evaluate the motion performance of the moored system under different operation conditions. The influences of the net buoyancy and the ocean current velocity on the motion of the underwater moored platform are investigated. The simulation results show that the underwater moored platform oscillates in water due to the periodically changed rotor forces. The system has a higher motion stability at a higher net buoyancy, with a smaller horizontal offset and a smaller cable inclination angle. The motion stability of the system also increases with the decreased ocean current velocity.