SWING

The project is devoted to the study of a new mode of propulsion for maritime transport: Wind-Assisted Ship Propulsion (WASP). The design of such wing-sails meets strict criteria and sea conditions which make it impossible to study at a 1:1 scale. Although, geometrically similar to wings used in aeronautics and blades of wind turbines, their operating range is extremely different because of the low speeds and high turbulence levels encountered. This means that very little is known about the aerodynamics of these new propulsion systems. This project aims at tackling this issue by providing a methodology for approaching full-scale aerodynamic of wing-sails. To achieve this objective, the project has been built on a dual and complementary approach. First, a downscaling approach will be deployed to reproduce realistic sea conditions but at the wind tunnel scale where physical mechanisms can be studied in depth. Then, combining experimental and numerical means of the consortium, the results will be upscaled to the real application dimensions with help of numerical modelling (CFD). Such strategies are pivotal in naval-ship designs and wind energy propulsion where models need to account for the highly turbulent environment conditions. In these conditions at high-Reynolds number regimes, passive systems such as wind turbines, sails or propellers are subjected to unsteady phenomena associated with the upstream turbulent flow whose characteristic scales are still poorly understood. It is therefore mandatory to understand how such turbulent flows can be reproduced and downscaled in well-controlled laboratory experiments. This approach should help us to study and to propose designs which are both optimal in terms of performances and resilient with respect to the operating conditions. To address these scientific challenges, the project combines PRISME & IAT large-scale wind-tunnel facilities of different sheer sizes, capable of replicating realistic atmospheric conditions, and numerical competences and resources from CWS, the industrial partner of the project. The scientific work is experimental, numerical, and theoretical; It tackles three different complementary scientific milestones: (i) the analysis of real atmospheric data and a proof of concept of how such atmospheric conditions can be reproduced in a wind tunnel using passive and active devices. (ii) A detailed analysis of the physical phenomena occurring over wing-sail across a wide range of scale, from the lab to the full scale. (iii) Finally, the analysis of wing-sails subjected to free-stream turbulent conditions along with adaptive strategies to improve their performances. Experiments will be performed at PRISME and IAT. CWS will undertake computations and provide the industrial feasibility of the developed strategies.