Scale Effects on Nominal Wake Fraction in Shallow Water: An Experimental and CFD Investigation

The investigation of the wake field and nominal wake fraction in shallow water is critical for understanding ship hydrodynamics in confined environments. While extensive research has been conducted on deep water wake behavior, limited studies have addressed the effects of shallow water and scale on wake characteristics. This study systematically examines the influence of water depth and scale on wake field and nominal wake fraction through a combined approach of experimental model testing and computational fluid dynamics (CFD) simulations. A series of towing tank experiments were conducted in shallow water conditions using the Aframax hull form, and the results were validated by numerical simulations performed with the CFD solver STAR-CCM+. The findings highlight a significant impact on wake fraction due to scale effects, revealing nonlinear trends across different Reynolds numbers. Based on these observations, a predictive equation for nominal wake fraction in shallow water is proposed. The applicability of the equation was assessed by applying it to the KVLCC2 benchmark hull form, demonstrating its potential for use with other similar hull forms. These findings enhance the understanding of wake field dynamics in confined waters, enabling more precise ship design, improved performance predictions, and greater overall efficiency.