Nonlinear Ocean Wave Models and Laboratory Simulation of High Seastates and Rogue Waves

Abstract

With the increasing demand for marine structures, including ships and wave energy devices, to operate in energetic, high seastates, the need for modeling and simulation of nonlinear ocean wave fields in large-scale wave basins is becoming essential. In response to this demand, a number of large-scale wave basins have been placed into operation over the years and larger and more sophisticated new ones are under planning and construction. In this article, the current state of practice and technical issues in modeling and simulation of high seastate ocean waves are summarized. A novel methodology for quantitative evaluation of the suitability of competing linear and nonlinear wave theories for a given wave field with multi-spatial measurements is presented. Preliminary results of an on-going study on wave modeling and analysis of measured data from a wave simulation performance study of the Oregon State University directional wave basin, using nonlinear wave theory (e.g. the nonlinear Schrödinger equation), nonlinear Fourier analysis and inference to the existence of rogue waves, are presented. Suggestions on future development of nonlinear wavemaker theories and numerical modeling and simulation of large-scale wave basin nonlinear wave generation are proposed. The article concludes with some observations and remarks on the importance of using an appropriate wave theory to determine the existence of nonlinear coherence structures, including breathers and rogue waves.