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Old   September 3, 2007, 03:18
Default Particle Tracking or additional variables
  #1
Andy
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hi,everyone.

i try to model the pollutants emited from vehicles. i don't know how to begin this work. From tutorial, i find the two ways above(Particle Tracking or additional variables) both seem to be able to model the vehicle pollutants.

i wonder which one is better? Anyone can give me some suggestion.

Thank you in advance!
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Old   September 3, 2007, 18:20
Default Re: Particle Tracking or additional variables
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Glenn Horrocks
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Hi,

Particle tracking is for tracking particles (obviously). If you wish to model particles this may be appropriate but it is not very good for modelling dissipative pollutants. For this case the additional variable approach is a good elementary approach, otherwise you need Eularian multiphase if you want to capture buoyancy of the various gas/vapours and possibly even chemistry if you want to go that far.

Glenn Horrocks
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Old   September 4, 2007, 01:59
Default Re: Particle Tracking or additional variables
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Andy
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Thank you very much!

but for the additional variable approach, the attribute of the pollutants such as density cannt be set in cfx11. the additional variable is nothing but different from the air. how to set some attribute for additonal vaiable?

in addition, i han't found much information about the Eularian multiphase.could you give me more?

Thank you very much!
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Old   September 4, 2007, 18:33
Default Re: Particle Tracking or additional variables
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Glenn Horrocks
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Hi,

You cannot set a density in the additional variable approach. The fluid can only have the properties of the surrounding fluid.

The Eularian Multiphase model is extensively discussed in the documentation. Have a look at tutorial 18 in CFX11.

Glenn Horrocks
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