Impact of harbor navigation channels on waves: A numerical modelling guideline

This study presents an intercomparison of a SWAN and SWASH wave model and 3D laboratory experiments for an existing navigation channel towards a harbor. Results show that the spectral refraction model SWAN underestimates the wave conditions in the channel and at the lee side of the channel especially - for longer waves travelling under a small angle with the channel - due to the neglect of the effects of wave tunneling by diffraction and evanescent modes. The phase-resolving non-hydrostatic 3D model SWASH does include these effects and performs reasonably well, though computational CPU demands are much higher. A modelling guideline is presented for application to other situations, showing that these effects need to be taken into account in optimizing the (layout) of the harbor; otherwise it may lead to under- or overestimation of the wave conditions and wave penetration into a harbor basin