Down-scale marine hydrodynamic analysis at the Norwegian coast from metocean to FSI—The NORA-SARAH open framework

Offshore wave studies often assume Gaussian processes and homogeneous wave fields. However, as waves approach the shoreline, complex coastal topo-bathymetry induces transformations such as shoaling, refraction, diffraction, reflection, and breaking, leading to increased nonlinearity and site-specific wave characteristics. This complexity necessitates detailed site-specific studies for coastal infrastructure design and blue economy planning.This work presents a dynamical downscaling procedure for analyzing wave–structure interactions from offshore metocean conditions. The open-access NORA3 and NORA10EI hindcast databases define offshore seastates and wind conditions, which are propagated to nearshore regions using the phase-averaged wave model SWAN. The outputs inform phase-resolving simulations with the fully nonlinear potential flow solver REEF3D::FNPF, incorporating an Arbitrary Eulerian–Lagrangian (ALE) method to compute wave forces via Morison’s formulation and to screen for severe wave loads, which are further examined using the fully viscous Navier–Stokes solver REEF3D::CFD. A one-way hydrodynamic coupling (HDC) between the potential flow and viscous solvers ensures accurate information transfer.The proposed NORA-SARAH framework, integrating NORA databases with SWAN-REEF3D-ALE-HDC, offers a robust approach for complex coastal environments. A case study in Southern Norway demonstrates its advantages over traditional significant wave height (Hs)-based or phase-averaged modeling-based practices, highlighting the necessity of this downscaling method.