Acoustic Analysis
Hi
I am trying to analyze the noise heard by the passenger inside the cabin (of vehicle) due to some external acoustic source as well as base excitation due to road.
I am using NVH application with Optistruct solver. I am able to analyze the base excitation due to road.
But I am not sure how to perform the analysis for noise generated by a far field source.
To be more precise how can I create acoustic cavity mesh for fluid outside the cabin and define acoustic source. (Acoustic cavity tab asks only to select structure components and seat components).
Thanks
Anmol
Answers
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I found the method in this thread. but I am wondering how can I define CACINF4 element type for only outermost elements because I need to specify grid points in definition.
Is there a way to extract element connectivity table for the faces or some other way please let me know?
Thanks
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Hi,
You can extract faces, move to a different component and change the element type to CACINF4
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Okay Thanks. For now I just made a very simple planar ambient field instead of sphere just to verify. I am getting same error as described in previous thread, ' *** ERROR 1684: FLUID element 1736620 points to non-fluid GRID 210175.'
I see that for some grids cd = -1. How do I resolve this. These grids lie inside the vehicle cavity.
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Hi @anmolk
To resolve this issue you need to card edit all the fluid grids and choose CD= -1 for them. (This has to be done for all the nodes except the constrained node). You can card edit all the fluid grids at the same time.
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Appreciate your help that worked.
I have couple of questions though about this procedure.
1. I ran the analysis for low frequency ranges <200Hz. Is it valid for higher frequencies as well f=1-2kHz? If it is how may I improve the accuracy?
2. Can I use infinite elements approach to analyze noise inside Composites structures as well?
Please let me know
Thanks
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Hi anmolk,
I'm planning to do the same kind of analysis where i want to analysis the noise levels outside of a cabin,
can u help on me that.
It will be hepful
Regards & Thanks
Subash K
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