Three-dimensional wave focusing in fully nonlinear wave models
Date of Original Version
Wave frequency focusing has been used in two-dimensional (2D) laboratory wave tanks to simulate very large waves at sea, by producing large energy concentration at one point of space and time. Here, three-dimensional (3D) frequency/directional energy focusing is simulated in a fully nonlinear wave model (Numerical Wave Tank; NWT), and shown to produce very large waves. This method alone, however, cannot explain why and how large waves occur in nature. Self-focusing, i.e., the slow growth of 3D disturbances in an initially regular wave train, is shown to also play a major role in the formation of "freak waves". Self-focusing is studied in a more efficient space-periodic nonlinear model, in which long term wave propagation can be simulated. The combination of directional/frequency focusing and self-focusing, and resulting characteristics of large waves produced, could be studied within the same NWT.
Proceedings of the International Symposium on Ocean Wave Measurement and Analysis
Brandini, Carlo, and Stéphan T. Grilli. "Three-dimensional wave focusing in fully nonlinear wave models." Proceedings of the International Symposium on Ocean Wave Measurement and Analysis 2, (2001): 1102-1111. doi:10.1061/40604(273)112.