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[GAMBIT] periodic boundary condition for a rectangular duct domain

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Old   May 24, 2013, 06:29
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Maxime Perelli
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you can provide your mesh file, I can check but only on Monday.

Are you sure you don't have this problem with symetry instead of periodic?
What about wall instead of periodic?

Give all the setup, density, viscosity etc...

You are handling a domain with huge dimensions (order of 100 km), is it right?
Seems to be quite big for a impeller if I refered to your picture, isn't it?
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Old   May 24, 2013, 07:29
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Quote:
Originally Posted by -mAx- View Post
you can provide your mesh file, I can check but only on Monday.

Are you sure you don't have this problem with symetry instead of periodic?
What about wall instead of periodic?

Give all the setup, density, viscosity etc...

You are handling a domain with huge dimensions (order of 100 km), is it right?
Seems to be quite big for a impeller if I refered to your picture, isn't it?
yes max
i,m sure that with symmetry and with wall in stead of periodic there is no problem.
i,m simulating a wind turbine which the radios of it,s rotor is 63 meters
the radius of outer volume is 180 meters and the height of that is about 900 meters.
the other bcs and situation are as:
velocity inlet 11 m/s
pressure outlet 0 gauge
tow faces as interior
wind turbine wall
i,m starting with simple situation so i set my turbine as stationary wall and laminar situation.
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Old   May 24, 2013, 07:43
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2 points:

*
Domain Extents:
x-coordinate: min (m) = -1.194447e+005, max (m) = -1.000000e+002

--> DX=119347m = 119 km
y-coordinate: min (m) = -1.680000e+005, max (m) = 6.120000e+005

--> DY=780000m=780 km
z-coordinate: min (m) = -1.200000e+005, max (m) = 6.000000e+004

--> DZ=180000m=180 km

In Gambit how big is your outer volume? (Gambit has no unit, if you only import the mesh, then it is automatically scaled in m)

*Did you specify your 2 faces as interior? (In Gambit, interior faces are automatically fused in interior domain). Do they appear as interior or wall in fluent?
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Old   May 24, 2013, 07:55
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Quote:
Originally Posted by -mAx- View Post
2 points:

*
Domain Extents:
x-coordinate: min (m) = -1.194447e+005, max (m) = -1.000000e+002

--> DX=119347m = 119 km
y-coordinate: min (m) = -1.680000e+005, max (m) = 6.120000e+005

--> DY=780000m=780 km
z-coordinate: min (m) = -1.200000e+005, max (m) = 6.000000e+004

--> DZ=180000m=180 km

In Gambit how big is your outer volume? (Gambit has no unit, if you only import the mesh, then it is automatically scaled in m)

*Did you specify your 2 faces as interior? (In Gambit, interior faces are automatically fused in interior domain). Do they appear as interior or wall in fluent?
i bring my geometry from catia into gambit,in catia they were in mm
so i interred my amounts in gambit with mm

i set that tow faces as interior in fluent too.
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Old   May 24, 2013, 08:05
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*then you have to scale your model
*you cannot set your faces as interior in fluent, since they are not supposed to exist, except if you set them in Gambit. Did you set them in Gambit as interior?
If not, then fluent shouldn't create them, and then something went wrong.
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Old   May 24, 2013, 18:09
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Quote:
Originally Posted by -mAx- View Post
*then you have to scale your model
*you cannot set your faces as interior in fluent, since they are not supposed to exist, except if you set them in Gambit. Did you set them in Gambit as interior?
If not, then fluent shouldn't create them, and then something went wrong.
dear max tnx really for all of your helps
i set the correct amounts for one of my walls and now it is working
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Old   June 5, 2013, 07:48
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Select boundaries as " wall "type only then give the names to the boundaries such that you can easily identify the which boundary is periodic and his shadow.
then In Fluent use command
mesh<enter>modify zones<enter>make periodic
give number of periodic and shadow boundaries <enter>
use yes for rotational no for translation
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