Horizontal and Vertical axis wind turbines: Impacts on the dynamics of a floating wind system

Floating Vertical Axis Wind Turbines (VAWTs) benefit from increased static stability, lower maintenance costs, and reduced aerodynamic wakes. However, to compete with Horizontal Axis Wind Turbines (HAWTs), further analysis is needed regarding the influence of foundations and wind turbine loads to provide a quantitative difference between the two technologies. This study compares the dynamics of floating offshore systems supporting HAWTs and VAWTs. The VAWT is simulated with a novel numerical model combining the Double Multiple Stream Tube method for aerodynamics and WEC-Sim for hydrodynamics, while the HAWT uses the tool MOST. The study aims to understand differences in productivity, loads, and displacements using the same floating foundation and mooring system under identical metocean conditions. Results show that VAWTs generate lower torque but higher wind loads on the turbine base. HAWTs exhibit reduced surge and pitch movements, providing greater stability and transmitting lower forces to the moorings compared to VAWTs.