POSTER 14 - Performance Optimization of a Whale-Inspired Oscillating Foil for Auxiliary Cargo Ship Propulsion
by M. ABGRALL (1,3), M. Sacher (2), P. Perali (2), B. Clément (1), R. Lecuyer-le-Bris (3)
(1) ENSTA, Institut Polytechnique de Paris, Lab STICC, CNRS UMR 6285, France, (2) ENSTA, Institut Polytechnique de Paris, IRDL, CNRS UMR 6027, France, (3) BLUEFINS, France
The reduction of fuel consumption and emissions in maritime transport relies on the development of auxiliary propulsion systems adapted to operational conditions. Among the most promising solutions, bio-inspired oscillating foils enable the conversion of vessel motions into propulsive thrust. However, the performance of such systems strongly depends on the encountered sea states. Consequently, for a given maritime route, the optimal foil geometry and control law are not unique. It is therefore necessary to develop design tools capable of identifying optimal system configurations (geometry and control) for various operating scenarios.
In this context, the present work proposes an optimization framework based on Gaussian process surrogate models to jointly determine the optimal foil geometry and kinematics. The foil kinematics is described by two degrees of freedom (heave and pitch), considering both sinusoidal and non-sinusoidal trajectories. The approach relies on a bi-objective optimization strategy to explore the trade-offs between mean thrust and hydrodynamic efficiency, under constraints representative of an industrial application case. Hydrodynamic performances are evaluated using a potential flow solver, while optimal configurations are validated through high-fidelity viscous simulations (RANS).
The results show that the use of non-sinusoidal trajectories, combined with bio-inspired geometries, can improve propulsive efficiency by up to 10% at fixed mean thrust, particularly at low Strouhal numbers. The developed tool provides a basis for the future development of adaptive control strategies under real operating conditions.
