Simple Pipe Acoustics - the very basics

Numerical methods and mathematical models of Elmer
Adev
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Re: Simple Pipe Acoustics - the very basics

Post by Adev »

I agree with you.
I have a spare high performance Radeon graphics card I'll install in my computer and try it all again. Maybe tomorrow ...
Adev
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Re: Simple Pipe Acoustics - the very basics

Post by Adev »

As I documented in the Installation Forum topic,
I continued drilling down prior versions of Paraview until I found one that works with Intel graphics cards. The latest one that thus works is Paraview Version 4.4 Qt4 for 64 bit Windows computers. No need yet to install a new graphics card
kevinarden
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Re: Simple Pipe Acoustics - the very basics

Post by kevinarden »

Have not used windows in 15 years so I would not know but found this

https://discourse.paraview.org/t/paravi ... ows-10/401
Adev
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Re: Simple Pipe Acoustics - the very basics

Post by Adev »

Great find Kevin,
Extrapolating from a dot, it confirms I'm not completely insane ;) and validates newer editions of Paraview have issues with Intel Graphics.
Your time and effort is much appreciated, thank you!
panosvar
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Re: Simple Pipe Acoustics - the very basics

Post by panosvar »

Hi,

Maybe this is a stupid question, by how can I change the direction of the wave in the boundary condition "In"? I.e. here the x-axis is perpendicular to the surface and I guess the wave has the same direction as x does.
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Re: Simple Pipe Acoustics - the very basics

Post by panosvar »

For example in Comsol is something like this:
Attachments
Capture.PNG
Capture.PNG (6.43 KiB) Viewed 4462 times
raback
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Re: Simple Pipe Acoustics - the very basics

Post by raback »

Hi

Maybe something like this?

Code: Select all

Boundary COndition 1 
  Name = "Incoming"
  Target Boundaries(1) = 1
$p0=1.0
$k1=10.0
$k2=2.0
$k3=1.0
  Pressure 1 = Variable Coordinate 
    Real MATC "p0*cos(k1*tx(0)+k2*tx(1)+k3*tx(2))"
  Pressure 2 = Variable Coordinate 
    Real MATC "p0*sin(k1*tx(0)+k2*tx(1)+k3*tx(2))"
-Peter
panosvar
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Re: Simple Pipe Acoustics - the very basics

Post by panosvar »

Hi raback,

Thanks for the quick response. Unfortunately, that didn't work, maybe I have to be more specific. I have a model in Comsol that can be seen in "model_comsol.PNG".

The top and bottom hexahedrals are PLMs that simulate some kind of absorption and their corresponding very top and very bottom layers are hard wall boundaries. The "labyrinth" lookalike is some kind of plastic and everything between this and the PLMs is supposed to be air. Also, the path that is created by this labyrinth is air as well, and the material that creates this path is made of plastic. The settings for the background pressure field are the like in the image above, along the y direction.

And the pressure field can be seen in "pressure_field.PNG". So the plane wave is propagating in the y direction.

Then I converted it with ElmerGrid and in Elmer the mesh can be seen in "model_grid_elmer.PNG".

I want to simulate the whole process in Elmer and confirm that it's the same. I have defined all properties for air & plastic. I already know from another post the there is no such thing as PLM in Elmer so I just put boundary conditions equal to -c. For the plastic "walls" I've set real and imag part of the flux to 0. However, I don't know how to tune the other settings to make this happen, and my first question is: Where should I apply this boundary condition supposing the wave is propagating from bottom to up in the y axis, in the very bottom layer? Or in the beginning of the "labyrinth"?

Edit: I don't know why the images cannot be seen in this page, so I just uploaded them.
Attachments
pressure_field.PNG
(135.05 KiB) Not downloaded yet
model_grid_elmer.PNG
(57.34 KiB) Not downloaded yet
model_comsol.PNG
(27.42 KiB) Not downloaded yet
Last edited by panosvar on 30 Oct 2019, 17:29, edited 2 times in total.
Adev
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Re: Simple Pipe Acoustics - the very basics

Post by Adev »

Hi panosvar,
I can't help you with your questions, but can let you know that your images are not visible on the forum page nor by right-clicking nor by copy and paste to another document. In my experience, the picture formats of .jpg or .png works … perhaps you can convert them to one of those and upload them again?
Adriaan
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Re: Simple Pipe Acoustics - the very basics

Post by mzenker »

Hi,

images are displayed inline if they are not larger than 1024x768 pixels.

Matthias
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