For those who work on or near the water, having a working knowledge of the unpredictability of ocean waves can be crucial to their survival. Deep-water wave groups tend to be unstable and act erratically, which can cause boats that aren’t ready to do so to capsize.
This rogue wave behavior is the result of modulation instability, which typically only takes place in the presence of waves moving in one direction. Wave focusing, which is the process of making waves stronger, is expected to get worse when it interacts with other wave systems.
Now, researchers from Kyoto University have shown that unstable wave groups can travel independently even when there is interference present in their environment.
According to the study’s lead author, Amin Chabchoub, “Our results seem to support the concept of an unperturbed nonlinear water wave group focusing in the presence of counter-propagating waves, implying that the wave states are directional.”
Experiments were carried out by the group using a water waves tank in order to validate the results obtained from computer simulations that were based on the coupled nonlinear Schrodinger equation. This nonlinear wave equation model takes into account how waves that are moving in two different directions interact with each other.
The findings of the team show that the model agrees well with the experiments, including the dynamics of rogue and counter-propagating waves.
The study of extreme ocean waves, along with other fields such as offshore engineering, nonlinear optics, electrical engineering, and plasma physics, stands to benefit from a better understanding of the role that nonlinearity plays. This is especially true for the study of extreme ocean waves.
In light of the findings and inferences drawn from Chabchoub’s investigation, it has been suggested that “our study may inspire further theoretical and experimental studies to improve our understanding of such dynamics in the cacophony of different wave systems.”
