CFD-based Analysis of Scale Effects on the Open-Water Performance of Ducted Propellers

This study investigates the scale effects on the open-water performance of a ducted propeller through RANS-based numerical simulations using the commercial CFD software STAR-CCM+. The simulations were conducted for both model- and full-scale conditions to analyze how scale influences hydrodynamic characteristics, particularly in the presence of a duct structure. The numerical results were validated against open-water test data obtained from experiments conducted by the Korea Research Institute of Ships and Ocean Engineering (KRISO), ensuring the credibility of the computational setup. To evaluate the effect of local flow interactions between the duct and the propeller blades, two rotational modeling approaches—Multiple Reference Frame (MRF) and Sliding Mesh—were applied and comparatively analyzed. The study also provides detailed comparisons of pressure distribution, wake flow, and performance coefficients between the two scales, identifying the primary contributors to scale-induced variations. The findings offer practical insights for the accurate prediction of full-scale ducted propeller performance based on model-scale analysis.