This is the second report in 17_025 study that deals with the computation of rudder open water characteristics using FINE/Marine Computational Fluid Dynamics (CFD) software package. It examines the rudder open‐water characteristics for two vessels, the Grand Princess and Al Shamal. These rudders are identified as F01 and G01 in the Flanders Hydraulics (FH) towing tank database, and are semi‐balanced horn rudders. The CFD approach used here follows the setup from the previous reports on this project (Van Hoydonck et al., 2024), adjusting the domains and mesh configurations particularly for this study. However, grid convergence study was already performed in the past; so, to avoid repeating the same processing, we have utilised the knowledge gained from previous rudder open‐water simulations conducted at FH. Due to the inherently fluctuating nature of the computed force and moment coefficients in rudder open‐water simulations, a Savitzky‐Golay filter is applied to improve the smoothness of final results.For each of the rudders, two geometries are generated for which CFD computations are executed to determine the influence of geometry modifications: sharp edges chamfered, rudder and horn (combined in a spade rudder geometry). The first geometry is referred to as the ”base” configuration (with separate horn and blade), and the second is addressed as the ”simplified” configuration (spade rudder). The results are presented in terms of longitudinal force, lateral force and yawing moment coefficients, and a comparison is made between the current numerical findings and the existing experimental data.The CFD results exhibit qualitatively correct trends over the investigated range of angles of attack. However, significant discrepancies are observed between the numerical and experimental data, especially for the lift coefficient. The main reasons for this are the disparity in Reynolds number between the towing tank tests and the numerical results, and the lack of inclusion of the horn in the experiments to determine the open water characteristics on the blade.

Title : FH reports. Flanders Hydraulics: Antwerp. Volume : 17_025_2 Issue : Pagination : VII, 17 + 9 p. app.