A comparative study of interaction of random waves with a cluster of structures on a berm with RANS and LES models

Abstract The interactions of random waves with a cluster of structures positioned in a gridded array are investigated through a series of experiments and high-fidelity RANS and LES simulations. The performances of two different turbulence models, k − ω SST and LES, are evaluated in terms of the predicted flow field and resulting loading on the structures, both in the time and frequency domains. The comparative analyses show that the k − ω SST model predicts the free surface elevations slightly better than that of the LES model. The k − ω SST model fails to resolve the velocity fluctuations leading to the underestimation of the flow kinetic energy. The k − ω SST model underpredicts the wave runup/rundown, as well as the depth-integrated pressure force, compared to the LES model. The wave runup heights and onshore-directed depth-integrated pressure forces are found to follow the Rayleigh distribution. The comparisons of the wave runup heights and corresponding onshore-directed hydrodynamic forces follow a relatively linear trend that is within the ∓ 95% confidence intervals.