Three-dimensional Wave Patterns Observed at the Sea Surface
by
Guillemette Caulliez
Institut de Recherche sur les Phénomènes Hors Equilibre, Marseille, France
Coauthors: Fabrice Collard

Observations at the sea surface reveal that wind wave fields are essentially three-dimensional, exhibiting conspicuous cross-hatched, short-crested or crescent-shaped wave patterns. The present work surveys the laboratory studies of the patterns. The experiments were concerned with the two most typical types of patterns: the rhombic wind wave patterns observed for short waves at the earliest stages of wind wave development, and the horse-shoes patterns observed for gravity waves at the onset of breaking. The main geometrical features of these patterns are first described using both visualisations and single-point wave measurements. The conditions of occurrence of each pattern are determined in terms of specific ranges of parameters such as wave scale and wave steepness. In both cases, we show that the wave field is strictly composed of a few basic harmonics. The possible mechanisms of the pattern formation are then examined and discussed within the framework of the weakly nonlinear wave-wave interaction theories (McGoldrick, 1965, McLean, 1982, Shrira et al., 1996, Annenkov & Shrira, 1999).

Date received: October 10, 2003