Nos tutelles


Nos partenaires


Accueil du site > Évènements > Séminaires > Séminaires IRPHE > Archives IRPHE > 2015

Mardi 29 Septembre 2015 / IRPHE

publié le , mis à jour le

Séminaire exceptionnel IRPHE

Ship propulsion in waves by flapping foils

Orateur : Kostas Belibassakis
School of Naval Architecture & Marine Engineering National Technical University of Athens, Greece

Résumé : Flapping foils located beneath the ship’s hull are investigated an unsteady thrusters, augmenting ship propulsion in rough seas and offering dynamic stabilization [1,2,3]. The foil undergoes a combined oscillatory motion in the presence of waves. For the system in the horizontal arrangement the vertical heaving motion of the hydrofoil is induced by the motion of the ship in waves, essentially ship’s heave and pitch, while the rotational pitching motion of the foil about its pivot axis is set by an active control mechanism. Potential-based panel method has been developed for the detailed investigation of the effects of free surface in harmonic waves, and the results are found to be in good agreement with numerical predictions from other methods and experimental data. Also, it has been demonstrated that significant energy can be extracted from the waves. Furthermore, we examine the possibility of energy extraction under random wave conditions using active pitch control. More specifically, we consider operation of the foil in head waves characterized by a given frequency spectrum, corresponding to specific sea states. The effects of the wavy free surface are taken into account through the satisfaction of the corresponding boundary conditions. Numerical results concerning thrust coefficient are shown, indicating significant performance under optimal operating conditions, verified also by recent experimental work [4]. Thus, the present method can serve as a useful tool for the design, assessment and optimum control of such systems extracting energy from sea waves and augmenting marine propulsion.

References :
1. Belibassakis K.A., Politis G.K., 2013, Hydrodynamic performance of flapping wings for augmenting ship propulsion in waves, Ocean Engineering Vol.72, pp.227-240.
2. Filippas, E., Belibassakis K.A., 2014, Hydrodynamic analysis of flapping-foil thrusters operating beneath the free surface and in waves, Engineering Analysis with Boundary Elements, Vol.41, 47-59.
3. Belibassakis K.A., Filippas, E., 2015, Ship propulsion in waves by actively controlled flapping foils, Applied Ocean Research, Vol.52, pp.1-11.
4. Bockmann, E., Steen, S., 2014, Experiments with actively pitch controlled and spring-loaded oscillating foils. Applied Ocean Research, Vol.48, pp.227-235.

Date et lieu  : le Mardi 29 Septembre 2015 à 14h00, salle de séminaire d’IRPHE