A THEORETICAL INVESTIGATION OF NOISE REDUCTION THROUGH THE CYLINDRICAL FUSELAGE OF A TWIN-ENGINE, PROPELLER-DRIVEN AIRCRAFT

Interior noise in the fuselage of a twin-engine, propeller-driven aircraft with two propellers rotating in opposite directions is studied analytically. The fuselage was modeled as a stiffened cylindrical shell with simply supported ends, and the effects of stringers and frames were averaged over the shell surface. An approximate mathematical model of the propeller noise excitation was formulated which includes some of the propeller noise characteristics such as sweeping pressure waves around the sidewalls due to propeller rotation and the localized nature of the excitation with the highest levels near the propeller plane. Results are presented in the form of noise reduction, which is the difference between the levels of external and interior noise. The influence of propeller noise characteristics on the noise reduction was studied. The results indicate that the sweep velocity of the excitation around the fuselage sidewalls is critical to noise reduction.

  • Corporate Authors:

    Langley Research Center

    National Aeronautics and Space Administration
    Hampton, VA  USA  23665
  • Authors:
    • Bhat, R B
    • Mixson, J S
  • Publication Date: 1978-12

Media Info

  • Pagination: 47 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00191218
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: NASA-TP-1325, L-12225
  • Files: TRIS
  • Created Date: May 11 1979 12:00AM