Analysis and Evaluation of Wingsails with Crescent-Shaped Profiles – from Aerodynamics to Aeroelasticity
Doctoral thesis, 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 thrust forces 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.
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 thrust forces 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.
fluid-structure interaction
wingsail
wind-assisted ship propulsion
cambered profile
aeroelasticity
Author
Heng Zhu
Chalmers, Mechanics and Maritime Sciences (M2), Marine Technology
Propulsive performance of a rigid wingsail with crescent-shaped profiles
Ocean Engineering,;Vol. 285, part 2(2023)p. 1-22
Journal article
Unsteady RANS and IDDES studies on a telescopic crescent-shaped wingsail
Ships and Offshore Structures,;Vol. 19(2024)p. 134-147
Journal article
Zhu, H., Chernoray, V., Ringsberg, J. W., Ramne, B., & Yao, H.-D. Experimental and numerical studies on moderate-Re aerodynamics of cambered thick wingsails in crescent shape.
Zhu, H., Chernoray, V., Ringsberg, J. W., Ramne, B., Shao, Y., & Yao, H.-D. Reynolds number sensitivity of cambered wingsail aerodynamics.
Zhu, H., Ringsberg, J. W., Ramne, B., & Yao, H.-D. Fluid-structure interaction analysis of a crescent-shaped wingsail.
Currently, more than 80% of the world’s traded goods are carried by ships. These massive cargo ships are the backbone of global trade, but they also come with significant environmental costs, accounting for around 2% of global greenhouse gas emissions. As the climate crisis accelerates, addressing the environmental impact of shipping has become a crucial step toward sustainable development. The International Maritime Organization (IMO) is actively working to reduce shipping emissions by 50% by 2050, compared to 2018 levels.
One of the most promising innovations in this area is wind-assisted ship propulsion (WASP) technology, which taps into the renewable power of the wind to reduce fuel consumption and greenhouse gas emissions. This PhD research contributes to this global effort by exploring a cutting-edge WASP approach: crescent-shaped wingsails. These modern wingsails are designed to be more efficient and user-friendly, potentially transforming maritime transport by making it cleaner and more sustainable.
The research adopts a multidisciplinary approach, combining computational simulations and physical experiments to understand the performance and mechanics of these wingsails. Using advanced computational fluid dynamics (CFD) models, the study predicts how air flows around the wingsails, capturing complex phenomena such as air turbulence and swirling vortices. These simulations are validated through wind tunnel experiments, ensuring the accuracy of the results. The study reveals that crescent-shaped wingsails can generate substantial thrust, potentially cutting fuel use by up to 10% for large ships, depending on wind conditions and routes. Furthermore, the research employs finite element analysis (FEA) to investigate how the wingsails’ lightweight structures respond to wind forces. By analyzing the interplay between aerodynamic loads and structural flexibility, this research highlights the importance of understanding how the wingsails’ structural deformations affect their performance. This insight is crucial for engineers designing next-generation wingsails that maximize efficiency and reliability.
By reducing fuel consumption, crescent-shaped wingsails not only lead to lower greenhouse gas emissions but also improve air quality in port cities and coastal regions, thereby supporting UN’s SDG 7 (affordable and clean energy). The research also has economic implications, as decreased fuel costs could lead to more affordable goods and services, benefiting societies worldwide.
One of the most promising innovations in this area is wind-assisted ship propulsion (WASP) technology, which taps into the renewable power of the wind to reduce fuel consumption and greenhouse gas emissions. This PhD research contributes to this global effort by exploring a cutting-edge WASP approach: crescent-shaped wingsails. These modern wingsails are designed to be more efficient and user-friendly, potentially transforming maritime transport by making it cleaner and more sustainable.
The research adopts a multidisciplinary approach, combining computational simulations and physical experiments to understand the performance and mechanics of these wingsails. Using advanced computational fluid dynamics (CFD) models, the study predicts how air flows around the wingsails, capturing complex phenomena such as air turbulence and swirling vortices. These simulations are validated through wind tunnel experiments, ensuring the accuracy of the results. The study reveals that crescent-shaped wingsails can generate substantial thrust, potentially cutting fuel use by up to 10% for large ships, depending on wind conditions and routes. Furthermore, the research employs finite element analysis (FEA) to investigate how the wingsails’ lightweight structures respond to wind forces. By analyzing the interplay between aerodynamic loads and structural flexibility, this research highlights the importance of understanding how the wingsails’ structural deformations affect their performance. This insight is crucial for engineers designing next-generation wingsails that maximize efficiency and reliability.
By reducing fuel consumption, crescent-shaped wingsails not only lead to lower greenhouse gas emissions but also improve air quality in port cities and coastal regions, thereby supporting UN’s SDG 7 (affordable and clean energy). The research also has economic implications, as decreased fuel costs could lead to more affordable goods and services, benefiting societies worldwide.
GEneric Multidiscaplinary optimization for sail INstallation on wInd-assisted ships (GEMINI)
Swedish Transport Administration (2023/32107), 2023-09-01 -- 2026-08-31.
Strategic research project on Chalmers on hydro- and aerodynamics
The Chalmers University Foundation, 2019-01-01 -- 2023-12-31.
WINDSTRUC - wind-assisted propulsion for commercial vessels
Swedish Energy Agency (51552-1), 2020-12-01 -- 2023-11-30.
Stena Shipping AB, 2020-12-01 -- 2023-11-30.
ScandiNAOS AB, 2020-12-01 -- 2023-11-30.
Areas of Advance
Transport
Energy
Subject Categories
Applied Mechanics
Fluid Mechanics and Acoustics
Marine Engineering
Infrastructure
C3SE (Chalmers Centre for Computational Science and Engineering)
Chalmers Laboratory of Fluids and Thermal Sciences
ISBN
978-91-8103-140-9
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5598
Publisher
Chalmers