A review is given of the fundamentals of diffraction theory and the application of the theory to several problems of aircraft noise generation, propagation, and measurement. The general acoustic diffraction problem is defined and the governing equations set down. Diffraction phenomena are illustrated using the classical problem of the diffraction of a plane wave by a half-plane. Infinite series and geometric acoustic methods for solving diffraction problems are described. Four applications of diffraction theory are discussed: the selection of an appropriate shape for a microphone, the use of aircraft wings to shield the community from engine noise, the reflection of engine noise from an aircraft fuselage and the radiation of trailing edge noise.

  • Supplemental Notes:
    • Presented at the Vki/AGARD Special Course, Brussels, 28 May-1 June 1979.
  • Corporate Authors:

    Langley Research Center

    National Aeronautics and Space Administration
    Hampton, VA  United States  23665
  • Authors:
    • Lansing, D L
    • Chen-Huei, L
    • Norum, T D
  • Publication Date: 1979-1

Media Info

  • Pagination: 14 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00192315
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: NASA-TM-80053
  • Files: TRIS
  • Created Date: Jul 31 1979 12:00AM