Field measurements in a flow around a hydrofoil: Some preliminary results

This work reports the first results of an experimental study aimed at investigating the flow field modified by a hydrofoil NACA 0012 immersed in a water current. The velocity measurements were carried out at the Hydraulic Laboratory of the DICATECh (Polytechnic University of Bari, Italy) using an ADV (Acoustic Doppler Velocimeter) and a PIV (Particle Image Velocimetry) system, in order to reconstruct the flow field and the turbulence characteristics. We obtained instantaneous and average velocity vector maps, as well as instantaneous streamlines maps, in the streamwise direction, in vertical frames located both upstream and downstream of the hydrofoil. Furthermore, the vertical velocity profiles in some selected sections were also examined. The analysis of the acquired data was also performed in the frequency domain. The principal results show that the velocity profiles obtained with the PIV and ADV are comparable and that the frequency of vortex shedding downstream of the hydrofoil is in agreement with Strouhal's theoretical relationship.