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Modeling flute-like instrument using libAcoustics. No harmonics.

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Old   February 7, 2018, 11:08
Default Modeling flute-like instrument using libAcoustics. No harmonics.
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buzz
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Hi everyone,

I am trying to do simulation of fluid flow and acoustic field in flute-like instrument. I used two solvers pisoFoam and rhoPimpleFoam. As for fluid flow rhoPimpleFoam gave me much better solution. It created oscillations on the labium of the flute, and thanks that in the resonator pipe pressure also started to oscillate, which is correct due to theory.

But results of libAcoustic calculation, are quite strange. FFT show some "harmonics" but on the level of 10kHz, and I expected first harmonic near 1,5kHz. Those harmonics, does not look like harmonics in flute.

Has anyone used libAcoustics library for similar purpose? Do you have any idea what I am doing wrong? I am sending my code in tar.gz file.

Also, I was trying to play this signal in Matlab or Octave. I used function soundsc, and I calculated Fs from my time step in OpenFOAM simulation, so it was 10e07. But it doesn't work, and it shows me error: unable to open audio playback stream. Any idea?


I would be very grateful for any advise. If you need any more information, please let me know.

Regards,
danadam
Attached Files
File Type: pdf fluteSimulationFFT.pdf (30.4 KB, 17 views)
File Type: pdf fluteRealFFT.pdf (15.2 KB, 16 views)
File Type: gz caseCurleLong4.tar.gz (5.5 KB, 4 views)
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Old   February 8, 2018, 10:48
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As for problem with Octave, I just resampled my signal from 10e7 to 44,1kHz and it worked. But still it did not resolve my main problem.
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Old   March 7, 2018, 16:33
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Quick answer: I received the PM you sent me, but unfortunately I'm not familiar enough with the libAcoustics library. Please try contacting the creators of that library at https://unicfd.ru/en/contacts/
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