Abstract
Predicting turbulence characteristics with coastal ocean models is essential for tidal energy converter deployment. While large eddy simulation provides a detailed representation of turbulence, computational limitations limit its use to smaller domains. We systematically evaluate whether coastal models can provide reliable turbulence prediction through progressive refinement of 3D representation. Four configurations (Levels 1-4) using terrain-following coordinates isolated impacts of horizontal resolution, vertical resolution, and layer distribution, validated against field measurements from the Salish Sea, WA. Tidal current predictions remained consistent across configurations, but turbulence properties proved sensitive to resolution. Increasing vertical resolution alone (11 to 41 σ-levels) was insufficient; finer horizontal resolution capturing bathymetric variations was essential. The optimized Level 4 configuration with geometric σ-level distribution achieved dissipation rate skill scores exceeding 0.90. Mellor-Yamada 2.5 outperformed k-ϵ in TKE prediction (skill scores 0.84-0.94 versus 0.72-0.81) due to better boundary layer parameterization. Well-configured coastal models effectively bridge the gap between simplified tools and costly high-fidelity modeling, offering the tidal energy industry practical turbulence data at commercially relevant scales.