Study on scale effect of ship on flow field and near-field wave generation

Ship resistance is one of the most important factors for ship design. Due to the inability to satisfy full similarity conditions, the scale effect between model and full-scale ships has garnered significant attention and become a major focus of the ITTC. Traditionally, studies on scale effects have often focused on resistance, while little research can be found about its underlying flow mechanisms and influence on near-field wave generation. Therefore, this paper investigates the flow characteristics around the KCS hull of different scales (scale ratios α = 1.0, 4.0, 31.6, 60.0) under Fr similarity conditions by CFD method using STAR CCM+. The near-field wave generation is analyzed in detail, with a focus on wave profiles around the hull, free surface wave elevation and wave cut, wake flow field, and the distribution of the pressure field. The study reveals the differences in near-field flow characteristics caused by scale-induced Re non-similarity and their impact on near-field wave generation. This research helps to further elucidate the influence of scale effects on the flow field, thus offering valuable insights for improving the accuracy of full-scale ship resistance predictions, leading to a reduction in full-scale resistance prediction error by up to 17.56% compared to traditional ITTC model-scale extrapolation methods (e.g., the Prohaska-based approach).