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Piston sound

  1. Oct 1, 2005 #1
    consider a piston in an engine with a stroke of 86 mm and RPM 8000 which gives the frequency of sound it is producing(due to compression and decompression) to be 133 Hz and wavelength 2.57 m.

    Then the pressure amplitude turns out to be 20000 Pa and the intensity of the sound wave to be 479000 W/m2.

    Is it just me or is the intensity of the sound much too high? Am I going wrong somewhere?
  2. jcsd
  3. Oct 2, 2005 #2
    Well, any takers? Is the sound intensity produced really that high or am I going wrong somewhere with my calculations. I used the following two formulas

    pressure amplitude = bulk modulus * wave number * displacement amplitude

    intensity of sound = pressure amplitude^2/(2*density of air*speed of sound)
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