Breaking of two-dimensional waves in deep water

Alexander Babanin
Swinburne University of Technology

Friday, May 1, 2009 at 3:30pm
Engr IV Room 57-124

Abstract
The breaking of deep-water surface waves represents one of the most interesting and challenging problems of marine hydrodynamics. Results will be presented on predicting the wave breaking onset caused by the modulational instability of wave trains and a detailed investigation of the properties of this onset in deep water. The study is conducted by means of both numerical simulations and laboratory experiments.

Simulations of evolution of steep-to-very-steep waves to the point of breaking are undertaken by means of the fully-nonlinear Chalikov-Sheinin model. Particular attention is paid to evolution of nonlinear wave properties, such as steepness, skewness and asymmetry, in the physical, rather than Fourier space, and to their interplay leading to the onset of breaking. The role of superimposed wind is also investigated. Detailed laboratory study is subsequently described, the theoretical predictions are verified and quantified.

Since these idealised two-dimensional results are ultimately intended for field applications, tentative comparisons with known field data are considered. Limitations which the modulational-instability mechanism can encounter in real broad-band three-dimensional environments are highlighted.

Biography
Alexander Babanin obtained his PhD in 1990 from the Marine Hydrophysical Institute of Sebastopol, Russia, in Physical Oceanography. During this time he performed research on spectral characteristics of wind-generated waves. Prior to joining the Swinburne University of Technology, Babanin was a research scientist in the Marine Hydrophysical Institute, Australian Defence Force Academy (Canberra), University of Adelaide (South Australia). Prof. Babanin's research is focused on wind-generated waves, and in particular on wave breaking and dissipation, air-sea interactions and atmospheric boundary layer, wave-induced turbulence and ocean mixing.