Yu. I. Troitskaya, D. A. Sergeev, О. S. Ermakova, G. N. Balandina
Institute of applied physics RAS, Russia

Studying of the wave breaking influence on the momentum transfer between wind flow and surface roughness by visualisation methods

A novel experimental PIV technique, suggested for the laboratory measurements of turbulent flows uses the continuous laser light and high-speed video filming, which enables to obtain statistical ensembles of the flow velocity fields. Application of the experimental technique to investigation of the wind field above surface waves enables to carry out direct measurements of the ensemble averaged velocity fields induced by surface waves in the airflow. Experimental results demonstrate features of the non-separated airflow for the ensemble averaged fields even for the case of steep and breaking waves, when the air flow separation from the wave crests can be clearly seen on the instantaneous velocity fields. It is shown that the ensemble averaged wind fields can be described in the framework of the semi-empirical model of turbulence.
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