Velocity and stresses of partially-reflected water waves in the presence of opposing wind

It is known that long waves (or swell) ruffled by an opposing wind tends to be dissipated, while shorter waves develop on top of them and travel in the wind direction. However, the long waves are mostly considered progressive and the effect of reflection is neglected. We present an experiment study of mechanically generated regular waves in partially-reflective conditions and observed how they interact with wind an opposing. We look at how different reflection conditions and spatial variability affect the water flow and the stresses within it. By breaking down the signal through a triple decomposition, we analyse the velocity components and compare the wave-induced Reynolds stresses with a theoretical model which takes into account partial reflection conditions (Addona et al., 2018). This model helps us understand the spatial variability of the wave-induced stresses and avoid misinterpretations of the experimental results, proving the role the key role of reflection. A quadrant analysis of the fluctuating velocities is performed to study the direction of momentum transfer, which always seems to be from the interface to the water below. The work provides novel experimental data of the flow field of partially-reflected water waves in the presence of wind.