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Performance analysis of propellers : improved coupling of BEM with X-foil
Citation Link: https://doi.org/10.15480/882.9356
Publikationstyp
Conference Paper
Date Issued
2024-04-04
Sprache
English
Author(s)
University of Texas at Austin, Texas, USA
Ocean Engineering Group, Department of Civil, Architecture and Environmental Engineering, University of Texas at Austin, Texas, USA
TORE-DOI
Start Page
163
End Page
169
Citation
8th International Symposium on Marine Propulsors (smp 2024)
Contribution to Conference
Publisher
Norwegian University of Science and Technology, Department of Marine Technology
ISSN
2414-6129
ISBN
978-82-691120-5-4
Peer Reviewed
true
The Boundary element method (BEM) is commonly utilized in the hydrodynamic calculation for propellers due to its relatively lower computational demand while simultaneously offering high fidelity. However, the BEM is based on the inviscid potential theory, and typically, the effect of viscosity is considered by either applying a constant empirical friction coefficient or adopting the local friction coefficient calculated by the ITTC-1957 formulation over the blade. Although both methods enhance the correlation of predicted open water characteristics, neither of them takes into account the development of the boundary layer. This study presents a 3D potential-based BEM coupling with a primarily 2D boundary layer solver, X-foil, known as the viscous/inviscid interactive (VII) method. This approach is intended to more accurately evaluate the effects of viscosity on the blade and predict open water characteristics. When applying the VII method to propellers, the boundary layer equations are solved on individual sections of the blade in an iterative manner. The model assumes that boundary layer growth mainly occurs in the streamwise direction within a constant radius but with considering the interaction effects from other sections and blades. Specifically, the original 2D influence coefficients in X-foil have been replaced by the 3D influence coefficients corresponding to the effects of boundary layer sources from panels at each strip and blade. Moreover, the model includes the effects of potentials due to other strips arising from the 3D formulations. The pressure distributions, skin friction coefficients on each blade section, and the open water characteristics of the propeller are compared either with full-blown Reynolds Averaged Navier-Stokes (RANS) simulations or experimental measurements. The results show that the predicted viscous pressure distributions at both the leading and trailing edges are markedly improved by accounting for the effects of potentials from other strips. This model demonstrates robustness and efficiency in predicting viscous effects and requires significantly less computational effort than the intensive 3D meshwork by RANS calculations.
Subjects
Boundary element method
Viscous/inviscid interactive method
Pressure distribution
Friction coefficient
DDC Class
620: Engineering
Publication version
publishedVersion
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Name
Wu-PerformanceAnalysisOfPropellersImprovedCouplingOfBemWithXfoil-1181-1-final.pdf
Type
Main Article
Size
2.22 MB
Format
Adobe PDF