Ocean Waves Larger Than Ever: A New Study Shakes Up Our Understanding of Wave Formation

When waves reach a certain steepness, they break. This process, crucial for weather forecasting, climate modeling, and the design of offshore structures, is still not fully understood. Until recently, most studies assumed that waves were two-dimensional to simplify theoretical and computational models. However, in the real ocean, waves often propagate in multiple directions, making them three-dimensional.

As Professor Frédéric Dias from ENS Paris-Saclay and University College Dublin explains, "Whether we like it or not, ocean waves are more often three-dimensional than two-dimensional. In 3D, there are more ways in which waves can break."

This new experimental study, led by Dr. Mark McAllister (University of Oxford) and Professor Ton van den Bremer (University of Oxford and TU Delft), investigates the impact of "directional spreading" – waves moving in multiple directions – on wave breaking. The international research team, including members from the University of Manchester, University of Edinburgh, and ENS Paris-Saclay, demonstrated that three-dimensional waves can far exceed the theoretical breaking limits set for two-dimensional waves.

A Game-Changing Discovery

The results show that waves with directional spreading can become four times larger than previously thought possible. "We demonstrate that in these conditions, waves can greatly surpass the commonly assumed upper limit before they break," says Sam Draycott, Senior Lecturer in Ocean Engineering at the University of Manchester. Once a traditional wave breaks, it forms a whitecap, signaling the end of its growth. However, three-dimensional waves keep growing even after breaking.

This discovery could have significant implications for the design of offshore structures such as wind turbines. "The three-dimensionality of waves is often overlooked in the design of offshore turbines and other structures," says Mark McAllister. "Our findings suggest that this could lead to designs that are less reliable."
A Unique Lab for Groundbreaking Experiments

These experiments were made possible thanks to the FloWave circular wave basin, a unique facility at the University of Edinburgh that can generate waves from multiple directions. "Recreating the complexity of real-world sea states on a laboratory scale is central to FloWave’s mission," says Dr. Thomas Davey, Principal Experimental Officer at FloWave. "This study takes these capabilities to a new level by isolating specific wave-breaking behaviors."

The development of new three-dimensional measurement methods was key to these breakthroughs. Using an innovative array of sensors, the researchers were able to measure wave heights with unprecedented spatial resolution, providing a much more detailed understanding of these complex phenomena.

This research opens the door to further studies on the dynamics of three-dimensional waves and could profoundly change our understanding of ocean physics, particularly in the context of climate change and the growing need for sustainable marine infrastructure.