An Effective CFD Approach to Modeling Barnacle Fouling: Comparing Five Turbulence Models

This study presents a computationally efficient approach for predicting frictional resistance caused by barnacle fouling using steady Reynolds-Averaged Navier-Stokes (RANS)-based simulations.Three barnacle types with varying surface coverage levels were modeled in a two-dimensional domain by applying experimentally derived roughness parameters to flat plates.Five eddy-viscosity turbulence models- and ShearStress Transport (SST) k -were evaluated to assess their accuracy in capturing the hydrodynamic effects of roughness.Wall functions incorporating Grigson's roughness correction were applied to represent the roughness-induced velocity profile displacement.The simulations were performed under steady-state RANS assumptions at the model scale Re = 1.8 -4.8 10 6 and the full scale Re = 2.5 10 9 .Ten barnacle-fouling configurations, covering three barnacle sizes and surface coverage levels ranging from 10% to 50%, were analyzed to represent realistic surface roughness conditions.Results were validated against model-scale experimental data and full-scale extrapolated data.Grid convergence and uncertainty analyses confirmed that discretization error was the dominant source of numerical uncertainty.Among the models, the Realizable k and SST k models provided the best agreement with experimental and extrapolated results, particularly for S-type and M-type barnacle surfaces.The study suggests that simple numerical techniques, when combined with appropriate turbulence models and validated roughness functions, can provide reasonable estimates of added resistance due to biofouling within the scope of the modeled conditions.These findings support the use of efficient computational fluid dynamics workflows for performance prediction in naval and commercial ship applications.