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Diss. (sammanfattning) Göteborg : Chalmers tekniska högskola, 2024

Seaborne transportation accounts for ~2% of global 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 an effective way to reach the target. In this context, this thesis aims to promote wingsails with crescent-shaped profiles through the assessment of their aerodynamic and aeroelastic performance, as well as long-term propulsive efficiency. This thesis provides an in-depth investigation into the unsteady aerodynamic and aeroelastic characteristics of wingsails, setting it apart from other related work. Conceptual designs of crescent-shaped wings were investigated using high-fidelity numerical simulations. Wind tunnel (WT) tests were conducted for validation. Flows were simulated with the unsteady Reynolds-averaged Navier-Stokes equations (URANS) and improved delayed detached eddy simulation (IDDES). Structures were analyzed with finite element methods. To simulate the fluid-structure interaction, a two-way coupled algorithm was used. Additionally, the long-term propulsion performance was assessed with an in-house program, ShipCLEAN. The aerodynamic analyses revealed that the crescent-shaped wingsails generate higher thrustforces compared to traditional symmetric airfoils, especially under sidewind conditions. However, unsteady aerodynamic characteristics due to strong flow separation were observed. Different structural configurations were evaluated, with a focus on balancing the weight, strength, and rigidity. The aeroelastic analyses pointed out significant fluid-structure interaction effects. The structural deformations have a notable influence on thrust generation. It means that aeroelasticity must be considered in the wingsail design and operation in practice. A long-term case study demonstrated that a large commercial ship equipped with a selected crescent-shaped wingsail achieves fuel savings of up to 10%, depending on wind conditions and operational strategies.