The single phase and cavitating tip vortex shed by a NACA 66-209 rounded tip hydrofoil is studied. Single phase measurements of instantaneous flow velocity are made by taking double pulsed holograms of microbubbles moving in and around the vortex core. The tailored air bubble technique of Ooi and Acosta (1983) is employed to measure both the mean and fluctuating single phase vortex core static pressure. Cavitation inception data are determined by visual inspection. The flow in the vortex core is shown to be highly unsteady. The r.m.s. axial velocity fluctuation can be as high as 0.2U sub infinity. Core pressure fluctuations are found to be greater than the freestream dynamic pressure. With saturated water, inception occurs at mean core pressures above the vapor pressure. The rapid establishment of fully developed trailing vortex cavitation when the cavitation number is reduced below inception is attributable to the small variation in mean core pressure with downstream distance. The inception index is shown to decrease dramatically with decreasing dissolved air content.

  • Supplemental Notes:
    • Conference paper
  • Authors:
    • Green, S I
    • Acosta, A J
  • Conference:
  • Publication Date: 0

Media Info

  • Features: References;
  • Pagination: 6p.

Subject/Index Terms

Filing Info

  • Accession Number: 00660840
  • Record Type: Publication
  • Source Agency: Maritime Technical Information Facility
  • Files: TRIS
  • Created Date: Jul 21 1994 12:00AM