A Numerical Investigation on Wave Spectrum Identification and Transformation From Deep to Shallow Waters for the Coastal and Offshore Installations

Abstract

Abstract Nowadays, many aquaculture and marine renewable energy facilities are developed at the shallow and intermediate water areas close to the bathymetric transition to the deep seas. The transition from deep to shallow water has a strong influence on the wave spectrum shape. Consequently, it is challenging to choose the appropriate spectrum for the sites of interest. In this study, a fully nonlinear potential flow (FNPF) model is used to investigate the wave spectrum transformations from deep to shallow water conditions. A series of JONSWAP spectra with different parameters is used as inputs. For each input spectrum, simulations are performed for wave propagations at constant shallow water conditions as well as for wave transformations from deep to shallow water conditions. The resulting spectra at the shallow water regions are compared to each other as well as the transformation (TMA) spectra. The differences are related to wave shoaling, reflection and breaking. The findings are confirmed in a computational fluid dynamics (CFD) domain. The study reveals the correlation between wave transformations and spectrum transformations at bathymetric variations. It is also found that a simulation of the complete wave transformation process produces a more accurate representation of the irregular wave field after the bathymetric transition than directly applying a specific spectrum at the shallow water region.