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Need help regarding acoustic model
Posted Aug 6, 2014, 4:10 a.m. EDT Acoustics & Vibrations, Modeling Tools & Definitions, Parameters, Variables, & Functions 2 Replies
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Hello Guys,
I am glad that I finally joined COMSOL community.
A bit of information about myself:
I am a student at Technion, a university in Israel, working our wind tunnel.
Recently, we had some issues related with acoustics in our wind tunnel so I decided to look into and figure out the cause. To be honest, I don't have a background in acoustics and not planning on diving too deep inside.
I recently started using COMSOL without any training and I am happy that I am moving ahead but slowly.
So the bottomline is I don't know acoustics and I don't know much of COMSOL and yet I want to solve a problem.
Now, coming on the key issue.
Our wind tunnel has an inlet which looks like a bellmouth. At the end of this bellmouth, there is a fine mesh and then the actual tunnel assembled together. And then another mesh and a tunnel. Okay will explain this in different words:
Bellmouth inlet :: fine mesh 1 :: tunnel 1 :: fine mesh 2 :: tunnel.
Idea of using a mesh is similar to using a perforated plate, that is to reflect back wide range of frequencies (standing waves generated by bellmouth) and not letting them coming inside the tunnel 1.
I tried to simulate this on COMSOL and defined fine mesh as "Interior Perforated Plate", but I am not sure if this feature simulated reflection or absorption of waves. Clearly in my system, I would like to filter them out by reflecting them back to inlet.
I am giving a dropbox link to my COMSOL file in here and request you to have a look and suggest if my approach is right or wrong.
For this model, I followed a paper which I am also attaching.
www.dropbox.com/s/1c9gebmebrwwyl5/tunnel_open_open%2025%20microns%20-%200.1mm%20thickness.mph
Thanks a lot.
Regards,
Judah
I am glad that I finally joined COMSOL community.
A bit of information about myself:
I am a student at Technion, a university in Israel, working our wind tunnel.
Recently, we had some issues related with acoustics in our wind tunnel so I decided to look into and figure out the cause. To be honest, I don't have a background in acoustics and not planning on diving too deep inside.
I recently started using COMSOL without any training and I am happy that I am moving ahead but slowly.
So the bottomline is I don't know acoustics and I don't know much of COMSOL and yet I want to solve a problem.
Now, coming on the key issue.
Our wind tunnel has an inlet which looks like a bellmouth. At the end of this bellmouth, there is a fine mesh and then the actual tunnel assembled together. And then another mesh and a tunnel. Okay will explain this in different words:
Bellmouth inlet :: fine mesh 1 :: tunnel 1 :: fine mesh 2 :: tunnel.
Idea of using a mesh is similar to using a perforated plate, that is to reflect back wide range of frequencies (standing waves generated by bellmouth) and not letting them coming inside the tunnel 1.
I tried to simulate this on COMSOL and defined fine mesh as "Interior Perforated Plate", but I am not sure if this feature simulated reflection or absorption of waves. Clearly in my system, I would like to filter them out by reflecting them back to inlet.
I am giving a dropbox link to my COMSOL file in here and request you to have a look and suggest if my approach is right or wrong.
For this model, I followed a paper which I am also attaching.
www.dropbox.com/s/1c9gebmebrwwyl5/tunnel_open_open%2025%20microns%20-%200.1mm%20thickness.mph
Thanks a lot.
Regards,
Judah
Attachments:
2 Replies Last Post Aug 10, 2014, 3:10 a.m. EDT
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Posted:
1 decade ago
Don't have the cad import module so I can't open that file.
Attach a couple of pics of the model, I'll take a look at them and see if I have suggestions.
Stefano
Attach a couple of pics of the model, I'll take a look at them and see if I have suggestions.
Stefano
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Posted:
1 decade ago
Thanks Stefano for your reply.
I am attaching some photos and a complete report generated by COMSOL.
Please have a look and suggest.
Regards,
Judah
I am attaching some photos and a complete report generated by COMSOL.
Please have a look and suggest.
Regards,
Judah
Attachments: