Wu, Thomas S.Thomas S.WuKinnas, Spyros A.Spyros A.Kinnas2024-04-122024-04-122024-04-048th International Symposium on Marine Propulsors (smp 2024)978-82-691120-5-4https://hdl.handle.net/11420/46493The 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 Specifically, the original 2D influence coefficients in X-foil have been replaced by the 3D influence coefficients corresponding to the effects of boundary layer sources from panels at each strip and blade.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.enhttp://rightsstatements.org/vocab/InC/1.0/Boundary element methodViscous/inviscid interactive methodPressure distributionFriction coefficientEngineering and Applied OperationsConference Paper10.15480/882.935610.15480/882.935610.15480/882.9294Conference Paper