Physical model tests under towing conditions of a novel floating wind-wave integrated platform

The combined development of wind and wave energy can significantly reduce economic costs and optimize marine space. The combined concept usually exhibits distinct static and dynamic stabilities during transportation phases, making dynamic research during the transportation stages critical. A novel semi-submersible wind-wave integrated platform with a “T”-shaped structure is proposed, and a physical model with and without a wind turbine installed is established to study the towing resistance, roll and pitch motion responses under towing conditions. A series of experiments are conducted in still water and regular waves, considering key factors such as towing speed, wave conditions, draft, and direction. Results indicate the platform's natural roll and pitch periods are approximately 10 s. The resistance increases with increasing of speed, and 5 knots balances stability and efficiency. At 2 m wave height, the maximum roll and pitch of platform are 0.34° and 2.59° respectively, meeting the requirements of towing specifications. Doubling the draft increases resistance by 51 %, and the roll and pitch increase and decrease accordingly, making it a potential measure to improve stability under extreme sea conditions. When towing in the 180° direction, the platform shows a trim-by-head floating state with greater resistance, which is inappropriate in towing operations.