Acoustic pressure amplitudes and phases were measured in model scale on the surface of a rigid semicylinder mounted in an acoustically treated wind tunnel near a prop-fan (an advanced turboprop with many swept blades) model. Operating conditions during the test simulated those of a prop-fan at 0.8 Mach number cruise. Acoustic pressure amplitude and phase contours were defined on the semicylinder surface. Measurements obtained without the semi-cylinder in place were used to establish the magnitude of pressure doubling for an aircraft fuselage located near a prop-fan. Pressure doubling effects were found to be 6dB at 90 deg incidence decreasing to no effect at grazing incidence. Comparisons of measurements with predictions made using a recently developed prop-fan noise prediction theory which includes linear and non-linear source terms showed good agreement in phase and in peak noise amplitude. Predictions of noise amplitude and phase contours, including pressure doubling effects derived from test, are included for a full scale prop-fan installation.

  • Corporate Authors:

    Hamilton Standard

    Windsor Locks, CT  United States  06096
  • Authors:
    • Magliozzi, B
    • Brooks, B M
  • Publication Date: 1979-10

Media Info

  • Pagination: 90 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00312833
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: NASA-CR-159668 Final Rpt.
  • Contract Numbers: NAS3-20614
  • Files: TRIS
  • Created Date: May 7 1980 12:00AM