Methods for the Evaluation of Wingsails with a Crescent-Shaped Profile
Licentiatavhandling, 2023

Seaborne transportation accounts for a large proportion of greenhouse gas (GHG) emissions. The International Maritime Organization (IMO) has stipulated that GHG emissions should be reduced by 50% before 2050 compared to 2018. The use of wind-assisted ship propulsion (WASP) is considered one of the most effective ways to reduce GHG emissions. Therefore, the present study aims to establish multidisciplinary numerical models for predicting and evaluating the propulsive performance and structural response of WASP systems. 

Conceptual designs of a set of telescopic wingsail rigs are generated. Numerical simulations, including computational fluid dynamics (CFD) simulations and finite element analysis, are performed for dimensioning and optimizing wingsail structures for ships to understand the fluid–structural interaction (FSI). Since the deformation of the wingsail structure that the surrounding flow excites is so large, the interaction between the flow and structure creates a coupled problem. Analysis of a crescent-shaped wingsail using an in-house software ShipCLEAN, which is based on a generic ship energy model, is conducted to evaluate this wingsail’s propulsive performance in comparison with other WASP concepts. 

It is concluded that wingsails with a sectional profile and significant camber have much better propulsive performance than those with conventional airfoil profiles because the potential thrust force coefficient is approximately 30% higher. It is also found that the external loads on the crescent-shaped wingsail show notable periodic oscillations due to strong flow separation, so it can be inferred that wingsails can suffer from remarkable vortex-induced vibration. This raises higher requirements on the strength and rigidity of the wingsail structure. Tip vortices are found to have negative impacts on thrust, and the sail can strongly influence the wake flow. It is also concluded from the structural analysis that the strength, especially the von Mises yield and compressive normal stress, is most critical among the assessment criteria that are considered when evaluating the wingsail structure. Using a strong frame to bear global bending and introducing a cubic-shaped mast prevents stress concentration and reduces the weight of the structures.

wind-assisted ship propulsion

rigid wingsail

light weight structure

crescent-shaped profile

wind-assisted ship propulsion.

Delta+Gamma i M-huset
Opponent: Jakob Kuttenkeuler, Professor, Institutionen för Teknisk mekanik, KTH, Sverige


Heng Zhu

Chalmers, Mekanik och maritima vetenskaper, Marin teknik

Zhu, H., Yao, H.-D., Thies, F., Ringsberg, J. W., & Ramne, B. (2023). Propulsive performance analysis of a rigid wingsail with crescent-shaped profiles based on unsteady RANS CFD.

Unsteady RANS and IDDES study on a telescopic crescent-shaped windsail

Proceedings of The 7th International Conference on Ships and Offshore Structures (ICSOS 2022),; (2022)p. 146-160

Paper i proceeding

Structure analysis of lightweight sail structures for wind-assisted ship propulsion

Advances in the Analysis and Design of Marine Structures - Proceedings of the 9th International Conference on Marine Structures (MARSTRUCT 2023),; (2023)p. 327-335

Paper i proceeding

Strategiskt forskningsprojekt på Chalmers inom hydro- och aerodynamik

Stiftelsen Chalmers tekniska högskola, 2019-01-01 -- 2023-12-31.

WINDSTRUC - vindassisterad framdrift för stora fartyg

Energimyndigheten (51552-1), 2020-12-01 -- 2023-11-30.

Stena Rederi AB, 2020-12-01 -- 2023-11-30.

ScandiNAOS AB, 2020-12-01 -- 2023-11-30.





Teknisk mekanik


Strömningsmekanik och akustik


C3SE (Chalmers Centre for Computational Science and Engineering)



Delta+Gamma i M-huset


Opponent: Jakob Kuttenkeuler, Professor, Institutionen för Teknisk mekanik, KTH, Sverige

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