Measurements of Velocity Profiles in the Aqueous Boundary Layer at a Wind-Driven Water Surface

A two-dimensional flow-visualization technique for the investigation of wind-induced currents in the boundary layer beneath the water surface is presented. Experiments were conducted at the Heidelberg wind-wave facility at conditions where either wave motion was suppressed by surfactants or was not present because of low wind speeds. A PIV setup enables the calculation of flow vector fields and velocity profiles in an area of 4 mm beneath the interface. Parameters of this layer, such as the friction velocity were deduced from these profiles