Numerical Analysis of an Articulated Hybrid Offshore Wind Turbine Concept

Abstract

The concept of a "hybrid offshore wind turbine" originated from articulated loading platforms (ALPS). In this study, we have developed a concept design for the major structural components. Orcaflex was used to create a numerical model. A yaw controller was included in the numerical model by calling external functions through Python script. We have simulated the turbine’s behavior with constant wind loads under different sea states and yaw rates. The primary objective was to investigate the torque exerted on the universal joint located at the seabed, a crucial design parameter for this wind turbine concept, as well as the turbine’s efficiency in various sea states and yaw misalignments. A total of 57 cases were simulated with various combinations of wind and waves. The results show that the structure’s stability is sufficient, with a maximum inclination of approximately 2.7 degrees in the roughest wave conditions. The torque is more sensitive to the yaw rate (𝜙��̇) than to the significant wave height, and the deceleration of the turbine’s yawing generates the highest torque values. Wave loads reduced the turbine’s efficiency. However, an increase in wave height did not significantly impact the generator’s efficiency since the structure’s inclination did not change significantly.