AN IMPROVED METHOD FOR PREDICTING THE EFFECTS OF FLIGHT ON JET MIXING NOISE

The NASA method (1976) for predicting the effects of flight on jet mixing noise was improved. The earlier method agreed reasonably well with experimental flight data for jet velocities up to about 520 m/sec (approximately 1700 ft/sec). The poorer agreement at high jet velocities appeared to be due primarily to the manner in which supersonic convection effects were formulated. The purely empirical supersonic convection formulation of the earlier method was replaced by one based on theoretical considerations. Other improvements of an empirical nature included were based on model-jet/free-jet simulated flight tests. The revised prediction method is presented and compared with experimental data obtained from the Bertin Aerotrain with a J85 engine, the DC-10 airplane with JT9D engines, and the DC-9 airplane with refanned JT8D engines. It is shown that the new method agrees better with the data base than a recently proposed SAE method.

  • Supplemental Notes:
    • Presented at the 97th Meeting of the Acoustical Society Of America, Cambridge, Mass., 11-15 Jun. 1979.
  • Corporate Authors:

    Department of the Navy

    The Pentagon
    Washington, DC  USA  20350
  • Authors:
    • Stone, J R
  • Publication Date: 1979

Media Info

  • Pagination: 28 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00198882
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: NASA-TM-79155 Conf Paper
  • Files: TRIS
  • Created Date: Oct 17 1980 12:00AM