Principles and Laboratory Tests on Wind-Wave Generation, Interaction and Breaking Processes

At the atmosphere-ocean interface, the interaction between the atmospheric and ocean boundary layers determines heat and momentum exchanges and can affect the global balance of substances in air and water. In addition, wave generation, transformation and breaking play key roles in many physical processes, as they are essential for the analysis and characterisation of the behaviours of artificial and natural marine infrastructures near coasts. Breaking waves are complex phenomena that are enhanced by the vorticity and generation of turbulence and their evolution, during breaking and near the seabed. The transformation of a wave train that is breaking on a slope depends on the transport of turbulent kinetic energy (TKE), which causes the advection and spread of turbulence and generates a vortex according to the type of breaking. These processes are complex and not fully elucidated. The laboratory provides powerful tools for investigating these processes more deeply by analysing the transfer between the atmospheric and oceanic boundary layers and the turbulent characteristics of the breaking waves. This chapter presents recent advances in laboratory testing that are based primarily on physical tests that were developed in a combined wave-wind flume.