EFFECTS OF FORWARD VELOCITY ON TURBULENT JET MIXING NOISE

Flight simulation experiments were conducted in an anechoic free jet facility over a broad range of model and free jet velocities. The resulting scaling laws were in close agreement with scaling laws derived from theoretical and semiempirical considerations. Additionally, measurements of the flow structure of jets were made in a wind tunnel by using a laser velocimeter. These tests were conducted to describe the effects of velocity ratio and jet exit Mach number on the development of a jet in a coflowing stream. These turbulence measurements and a simplified Lighthill radiation model were used in predicting the variation in radiated noise at 90 deg to the jet axis with velocity ratio. Finally, the influence of forward motion on flow-acoustic interactions was examined through a reinterpretation of the 'static' numerical solutions to the Lilley equation. (Author)

• Corporate Authors:

  National Aeronautics and Space Administration

  600 Independence Avenue, SW
  Washington, DC  United States  20546
• Authors:
  • Plumblee, HEJ
• Publication Date: 1976-7

Media Info

• Pagination: 389 p.

Subject/Index Terms

• TRT Terms: Aircraft noise; Anechoic chambers; Flight simulators; Flow; Jet engines; Jet propelled aircraft; Laser doppler velocimeters; Noise; Turbulence; Velocity; Wind tunnels
• Uncontrolled Terms: Flight simulation; Flow velocity
• Old TRIS Terms: Free jets; Jet flow; Turbulent mixing
• Subject Areas: Aviation; Environment;

Filing Info

• Accession Number: 00145765
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: NASA-CR-2702 Final Rpt.
• Contract Numbers: NAS3-18540
• Files: TRIS
• Created Date: Jan 16 1977 12:00AM