Propulsive performance of a rigid wingsail with crescent-shaped profiles

Artikel i vetenskaplig tidskrift, 2023

Wind-assisted ship propulsion is considered an effective method for reducing greenhouse gas emissions. This paper presents numerical analyses of the aerodynamics of a single rigid wingsail conducted using the unsteady Reynolds-averaged Navier–Stokes (uRANS) equations. The wingsail is designed with a new sectional profile: a crescent-shaped foil. This new profile and the classical NACA 0015 profile were compared. Simulations were performed in two and three dimensions, with a focus on key physical quantities such as the external loads on the wingsail, the flow field, and the propulsive performance. It is concluded that the wingsail with the crescent-shaped section has higher propulsion efficiency than the NACA 0015. However, stronger flow separation was detected for the crescent-shaped section. As the separation deteriorates, the flow unsteadiness, challenges the strength and stability of the wingsail structure. The three-dimensional simulations of both profiles, particularly NACA 0015, show that the tip vortices induced from the side edge of the wingsail account for substantial negative effects on the propulsion performance. A case study revealed that installing a wingsail with a crescent-shaped profile reduced fuel consumption by 9% compared with no wingsail.