Abstract
Flapping-foil thrusters arranged at the bow of the ship are examined for the exploitation of energy from wave motions by direct conversion to useful propulsive power, offering at the same time dynamic stability and reduction of added wave resistance. In the present work, the system consisting of the ship and an actively controlled wing located in front of its bow is examined in irregular waves. Frequency-domain seakeeping analysis is used for the estimation of ship-foil responses and compared against experimental measurements of a ferry model in head waves tested at the National Technical University of Athens (NTUA) towing tank. Next, to exploit the information concerning the responses from the verified seakeeping model, a detailed time-domain analysis of the loads acting on the foil, both in head and quartering seas, is presented, as obtained by means of a cost-effective time-domain boundary element method (BEM) solver validated by a higher fidelity RANSE finite volume solver. The results demonstrate the good performance of the examined system and will further support the development of the system at a larger model scale and the optimal design at full scale for specific ship types.
Highlights
Extensive research concerning flapping-foil thrusters, including numerical modeling and experimental verification, has shown that the above systems, operating under conditions of optimal wake formation, can achieve high levels of propulsive efficiency; see, e.g., ref. [1]
The results show that the additional thrust generated by the dynamic wing, in conjunction with the reduction of added wave resistance due to dynamic stabilization of a ship in waves, will enable the engine to operate in part-load without compromising vessel speed, resulting in an additional positive effect on its emission profile
The present study indicates that the dynamic wing system can operate effectively both in head and quartering seas
Summary
Extensive research concerning flapping-foil thrusters, including numerical modeling and experimental verification, has shown that the above systems, operating under conditions of optimal wake formation, can achieve high levels of propulsive efficiency; see, e.g., ref. [1]. Extensive research concerning flapping-foil thrusters, including numerical modeling and experimental verification, has shown that the above systems, operating under conditions of optimal wake formation, can achieve high levels of propulsive efficiency; see, e.g., ref. The ship undergoes moderate or higher-amplitude oscillatory motions due to waves. In this case, the ship motions could be exploited for providing the foil heaving motion free of cost, especially if the foil is located at the bow; see, e.g., refs. In the framework of Seatech H2020’s project entitled “ generation short-sea ship dual-fuel engine and propulsion retrofit technologies” (https://seatech2020.eu/, accessed on 15 November 2021), a concept of symbiotic ship engine and the flapping thruster innovation is studied, that when combined, are expected to lead to a significant increase in fuel efficiency and emission reductions. The results will support the design of a full-size wing, including strength, fatigue and service life considerations, as well as actuation and a mechanical wing-retractability system in calm and heavy weather conditions, in order not to add to the resistance and protect the system, respectively
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call