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I Vulcan howl - aerodynamic calculations

  1. Jun 9, 2016 #1
    Hi guys and girls! Here's a hard one I need help wit. I really want it resolved because I sincerely love it.

    There's an aerodynamic phenomenon called 'the Vulcan howl'.

    It occurs when engines are employed at maximum power or more (maximum power in aircraft is only a recommended limit, in a problematic situation you can request emergency power from the system basically giving engines as much fuel and air as possible hoping they don't break). It's a reverberation caused by the configuration of the air intakes interacting with the air flow and pressure differentials.

    I'm wondering if it can be calculated, simulated or otherwise predicted if a certain air intake will generate sound under some conditions? I want to build a large model aircraft capable of making a Vulcan howl (higher pitch, of course). And no, scaling it down didn't work.

    Anyone know where to look for information on predicting this? Google has been of no help since I either end up with no results or results written by high-school level, self appointed professors.

    Please. Help me PhysicsForums, you're my only hope!
  2. jcsd
  3. Jun 9, 2016 #2


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    Article here describes the cause...

    What I would do is sample the original noise and play it back through an on board speaker. Some electric powered model aircraft have been fitted with similar speaker systems to replicate the sound of old rotary engines or whatever the original had.
  4. Jun 9, 2016 #3


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    You aren't going to have much luck simulating it unless you have access to large compute clusters and CFD software capable of aeroacoustic calculations. It's really not something that could be done without quite a bit of expertise in the field. Your scaled down version likely didn't work because any structural resonance would have changed, likely shifting to a higher frequency and requiring a faster air stream to excite it.
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