Experimental Investigation of Droplet Trajectories and Airflow Above Breaking Waves

Reyna Ramirez, Petter Vollestad and Atle Jensen, University of Oslo, Mathematics, Oslo, Norway
Within the marine boundary layer the interaction between air and water is constant and takes different forms. An interesting example is the artic ocean spray, generated by wave impact and wind, which can cause severe icing on vessels. Understanding this phenomenon is important for the safety of people, ships and installations that operate in the arctic environment.

In this study we performed lab-scale experiments of breaking waves, to describe the trajectories of the droplets in the spray generated by wave impact and wind.

The experiments were conducted in the wind-wave flume of the Hydrodynamics Laboratory at the University of Oslo. Focusing waves generated by a wavemaker provided highly repeatable wave breaking events. A fan was used to produce wind within a closed section above the waves. The airflow over breaking waves was measured using Particle Image Velocimetry, while 3D Particle Tracking Velocimetry was used to reconstruct the droplets trajectories. The main objective is to understand the dynamics and characteristics of the spray cloud under different wind conditions. The results of these experiments can be an important input for simulations, and in the future assist the the development of accurate models which can be used to reduce the risk associated with icing of arctic structures.