A RING-SOURCE MODEL FOR JET NOISE

A model consisting of two ring sources was developed to study the direct radiation of jet noise in terms of correlation, coherence, and phase and also to aid in solving the inverse radiation problem of determining the noise source in terms of far-field measurements. The rings consist of discrete sources which are either monopoles or quadrupoles with Gaussian profiles. Only adjacent sources, both within the rings and between rings, are correlated. Results show that from the far-field information can be used to determine when the sources are compact or noncompact with respect to the acoustic wavelength and to distinguish between the types of sources. In addition, from the inverse radiation approach, the center of mass, the location and separation distance of the ring, and the diameters can be recovered.

• Supplemental Notes:
  • Conf-Presented at the 95TH Meeting of the Acoust. Soc. Of AM., Providence, 14-19 May 1978.
• Corporate Authors:

  Langley Research Center

  National Aeronautics and Space Administration
  Hampton, VA  United States  23665
• Authors:
  • Maestrello, L
• Publication Date: 1978-4

Media Info

• Pagination: 41 p.

Subject/Index Terms

• TRT Terms: Acoustic measuring instruments; Acoustics; Aircraft noise; Density; Far field; Jet engines; Jet propelled aircraft; Mass; Mathematical analysis; Mathematical models; Noise generators; Probability density functions; Sound; Sound; Sound level; Variables; Wavelength
• Uncontrolled Terms: Noise contours
• Old TRIS Terms: Acoustic measurement; Density functions; Jet engine noise; Normal density functions; Radiation distribution; Rings; Singularity mathematics
• Subject Areas: Aviation; Environment;

Filing Info

• Accession Number: 00185744
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: NASA-TM-73959
• Files: TRIS
• Created Date: Dec 29 1979 12:00AM