'Super rogue wave' scuppers Lego pirate
Australian experiment shows how giant waves emerge
Video (.mov) Pity the poor Lego pirate in the video below: there he is, placidly riding over tiny waves, when a rogue wave arrives and upends his vessel.
The video looks trivial, but it has a serious implication: the ANU scientists that put it together did so as part of the world’s ongoing effort to understand rogue waves that menace shipping and arrive without warning.
The ANU team, working with colleagues from Hamburg University of Technology and the University of Turin, demonstrated that a particular condition known as a “Peregrine soliton” can arise in apparently calm seas, causing a “super rogue wave” much larger (relative to the ambient conditions) than has previously been measured.
Peregrine solitons were first proposed in the early 1980s by a mathematician, Howell Peregrine of the University of Bristol, and first observed in optics. The wave undergoes a compression, increasing its amplitude (as you can see in the video).
Over to the ANU’s statement: “The large amplification of the rogue wave peak above the normal waves around it suggests the existence of a new class of waves – the so-called ‘super rogue waves’,” explains Professor Nail Akhmediev of the ANU’s Research School of Physics and Engineering.
“Our results show that, even in a sea characterised by small waves, rogue waves can naturally develop due to the nonlinear dynamics of the surface elevation. This is an extraordinary fact that could explain some mysterious observations of rogue waves in calm sea states.” ®
Video source: Physical Review - original here. ®