Directional Coherent Wave Group From an Assimilated Non-linear Wavefield

Frontiers in Physics

Amin Chabchoub¹  Takuji Waseda²  Shogo Watanabe²  Tsubasa Kodaira²  Takehiko Nose²  Wataru Fujimoto³ 

[1] Centre for Wind, Waves and Water, School of Civil Engineering, The University of Sydney, Sydney, NSW, Australia;Marine Studies Institute, The University of Sydney, Sydney, NSW, Australia;Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan;Nippon Kaiji Kyokai (ClassNK), Tokyo, Japan;

关键词: ocean waves;    wave groups;    observational tower;    stereo imaging;    higher-order spectral method;    data assimilation;    non-linear Schrödinger equation;    directional envelope soliton;   

DOI  :  10.3389/fphy.2021.622303

来源: Frontiers

【 摘 要 】

The presence of coherent wave groups in the ocean has been so far postulated but still lacks evidence other than the indication from the radar images. Here, we attempt to reconstruct a wave field to monitor the evolution of a directional wave group based on a phase resolving two-dimensional non-linear wave model constrained by the stereo images of the ocean surface. The reconstructed wave field of around 20 wavelength squared revealed a coherent wave group compact in both propagating and transverse directions. The envelope of the wave group seems to be oriented obliquely to the propagation direction, somewhat resembling the directional soliton that was theoretically predicted and experimentally and numerically reproduced recently. A comparison with a constrained linear wave model demonstrated the coherence of the non-linear wave group that propagates for tens of wavelengths. The study elaborates a possibility of a spatially coherent short crested wave group in the directional sea.

【 授权许可】

CC BY