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Old   December 19, 2006, 15:33
Default normal injection from pipe flow
  #1
Fred Song
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The problem is:

Water flows into a pipe which is closed at another end and has hundreds of holes along the axial length. The injection of water to the surrounding fluid from these holes is the major concern. The meshing of hundreds of holes and the region of the jets seems almost impossible to me. Any suggestions about meshing or alternatiev simulation approaches are highly appreciated!

Thanks and Regards!

Fred

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Old   December 19, 2006, 20:30
Default Re: normal injection from pipe flow
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Jim_Park
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For a first cut you might try making each hole square/rectangular, deltaz by r*delta-theta. The mixing details might not be right, but the gross transfer of mass, momentum and energy due to the injection should be the correct order of magnitude. This would require the number of cells for the pipe surface to be twice the number of holes if the pipe surface had 50% hole area.

I can't imagine how to mesh all those holes in detail - or that the resulting numbers would have a lot more credibility.
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Old   December 20, 2006, 03:29
Default Re: normal injection from pipe flow
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JM
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I did a similar case where I had 1032 holes. meshing this holes of less than 0.08 inch diameter in a geometry of more than 1 meter in dia was impossible. I assumed it as a porous medium and worked very well.

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Old   December 20, 2006, 04:14
Default Re: normal injection from pipe flow
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Anton Lyaskin
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It depends upon what do you want to get - if it's some bulk parameters then you can go for porous medium, and if you want some fine details then you can take a short piece of your pipe with 5-10 holes and periodic boundary conditions
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Old   December 20, 2006, 09:30
Default Re: normal injection from pipe flow
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Jim_Park
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Nice!
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Old   December 21, 2006, 05:10
Default Re: normal injection from pipe flow
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msureshkumar
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Assuming porous media will wrok effectively and you can model all holes as cylinder and define it as fluid.
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