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Data From A Cut Line With MATLAB Livelink
Posted 20 févr. 2019, 14:18 UTC−5 Acoustics & Vibrations, LiveLink for MATLAB Version 5.4 2 Replies
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Hello,
I am having a similar experience as Pierre Guilleme (linked above), but with an acoustics model. I wish to export the imaginary component of acoustic pressure along a cut line to MATLAB and am finding some sort of jitter (supplementary points as Pierre calls them) in my MATLAB data. Two figures are attached for reference.
My model: Frequency Domain: An idealized 3D pipe acoustics model straight out of a textbook (no crazy boundaries, etc). A Cut Line has been defined along the center axis of the pipe. Using a Line Graph in COMSOL, I can easily plot imaginary pressure the expected smooth curve.
In MATLAB, I am using the command
data = mphinterp(model,{'imag(acpr.p_t)'},'dataset','cln1','solnum',1);
to retrieve the values for the first solution of my frequency sweep.
What are these extraneous points? Is there a more efficient way to export this data into MATLAB?
Regards,
Michael Rouleau
Attachments:
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Interp doesn't always produce results in the order they appear in the geometry
Try this:
[p,s]=mphinterp(model,{'imag(acpr.p_t)' 'cln1x'},'dataset','cln1','solnum',1);
plot(s)
You'll see that the arc length is not increasing.
Do this instead:
[ss,idx]=sort(s);
plot(ss,p(idx))
Lars Gregersen
Comsol Denmark
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Lars,
Your response was extremely helpful. It makes perfect sense now - thank you very much!
Michael Rouleau