Three different hydrofoil sections were investigated in the recently renovated High-Speed Cavitation Tunnel (HiCaT) at the University of New Hampshire: a NACA 0015 (reference foil), a NACA 63-424, and a bidirectional version of the NACA 63-424 hydrofoil. Bi-directional hydrofoils are of interest for marine renewable energy conversion, since they allow the elimination of pitch control mechanisms on marine hydrokinetic turbines. Hydrofoil lift and drag were measured for different velocities, pressures, and angles of attack. For some experimental conditions, comparative PIV measurements were performed in the near-wake region. A cavitation inception model for marine hydrokinetic turbines was derived. Cavitation numbers for inception were obtained for the two NACA 63-424 foils by varying pressure at constant speed as well as by varying speed at constant pressure. The performance of the NACA 63-424 and the bidirectional NACA 63-424 was compared.
