Modelling rogue waves in 1D wave trains with the JONSWAP spectrum, by means of the High Order Spectral Method and a fully nonlinear numerical model

Probability of rogue wave occurrence due to modulational instability in unidirectional JONSWAP sea states are investigated. This investigation has been conducted based on the quantitative indicators of Benjamin-Feir index (BFI), Π-number and kurtosis, which are used to represent instability in wave trains. Evolution of wavefields is simulated using the fully nonlinear phase-resolving numerical model of Chalikov-Sheinin (CS) and the high order spectral model of HOS-Ocean. Effects of the high-frequency end (tail) of the spectrum on modulational instability and rogue wave evolution are discussed considering four different tail lengths.