NOISE DUE TO FULLY DEVELOPED TURBULENT FLOW EXHAUSTING FROM STRAIGHT AND BENT PIPES

Noise in flow-ducts can be generated by acoustic sources such as fans, compressors or valves. Aerodynamic turbulence inside the pipe, however, can also generate acoustic power. The experiments and results described in this paper are a part of a study of noise transmission through pipe walls. The radiated power from fully developed turbulent flow exhausting from a circular pipe at subsonic speeds was measured in 1/3 octave bands. It was found that the turbulence in a straight pipe, of a length to diameter ratio L/D=360, produces no additional sound power when compared to jet mixing noise. Inserting a radiused 90 degrees bend, with a bend to pipe radius ratio of 17, also leaves the jet mixing noise unaffected. However, when a 90 degrees mitred bend is added to the pipe the exhaust radiated noise exceeds the predicted jet noise, particularly at low velocities. Also for a mitred bend the radiated power grows with approximately the sixth power of velocity. As the velocity increase, the jet mixing noise eventually takes over and is expected then to be the dominant noise source. These results are significant for predicting noise in piping systems and for designing quiet piping systems.

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  • Corporate Authors:

    Academic Press Incorporated

    Berkeley Square House, Berkeley Square
    London W1,   England 
  • Authors:
    • Kuhn, G F
    • MORFEY, C L
  • Publication Date: 1976-1

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Filing Info

  • Accession Number: 00139402
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Sep 16 1976 12:00AM