Nonlinear Wave Interaction and Its Applications to the Analysis of Ocean Waves

Interactions among free waves result in bound waves, which may significant affect resultant wave properties in an ocean wave field, especially when waves are steep. Since the measurements record the resultant properties, the presence of bound waves makes it inaccurate to analyze the measurements of steep ocean waves using linear spectral methods. To overcome this difficulty, Hybrid Wave Models (HWM) developed recently, separate bound waves from free waves in the decomposition of an irregular wave field as well as the prediction of its resultant properties. To ensure the convergence, the HWMs selectively use the conventional and phase modulation approaches to address the nonlinear interactions between free waves of different frequency ratios. The models are able to decompose a wave field accurately and hence can predict the wave properties accurately and deterministically based on the time-series measurements. Examples of their applications to the analyses of laboratory and field measurements are given to demonstrate the usefulness of HWMs.