Analytic study of a new conceptual propulsion device for ships

Performance improvement of a vibration driven system for marine vessels

“…The working principle of a propulsion system based on vibrating devices subject to various kinds of friction and or drag forces that simultaneously hinder and cause the motion preferentially along a direction with respect to the opposite one has been studied by many authors [1][2][3][4][5][6][7][8][9][10][11][12]. These researchers have confirmed the real possibility to obtain a displacement along a certain direction.…”

“…Then, the attempt to evaluate if new marine propulsion systems are possible and convenient could be beneficial. From this point of view in [10] an analytical numerical study of a vibrating propulsion device that could be adopted to move bodies partially or totally submerged is illustrated. This device does not consider the utilisation of propellers, it uses centrifugal force that arises, for example, from the rotation of a pair of counter rotating masses.…”

“…As the stern of the hull is suitably shaped, the hydrodynamic drag force during the backward motion is significantly higher Fig. 1 Kinematic scheme of the propulsion system equipped with (a) one [10] and (b) two pairs of counter rotating masses. Fig.…”

“…Fig. 2 Simplified kinematic scheme based on sliding fit of the propulsion system equipped with (a) one [10] and (b) two rotating masses. than that which is produced during the phase of forward moving.…”

“…Consequently, a forward displacement resultant of the whole hull-device system corresponding to each complete rotation of the counter rotating masses is generated. The equations of motion of the system just described have been obtained in [10] and it has been shown that, by integrating such equations, actually the system behaves as illustrated. These results will be utilized to develope the improved propulsion device illustrated in the following paragraphs.…”