# Does somebody can help me??

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May 20, 2010, 18:31
Does somebody can help me??
#1
Member

tom
Join Date: Feb 2010
Posts: 46
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Hi all,Note: Separating wall zone 11 into zones 11 and 1.
When I import the mesh to fluent, it always say

wall_bottom -> wall_bottom (11) and wall_bottom:001 (1)
Note: Separating wall zone 12 into zones 12 and 15.
wall_top -> wall_top (12) and wall_top:015 (15)
Note: Separating interior zone 16 into zones 16 and 17.
default-interior -> default-interior (16) and default-interior:017 (17)
Note: Separating interior zone 16 into zones 16 and 18.
default-interior -> default-interior (16) and default-interior:018 (18)

periodic_3
periodic_2
periodic_1
fluid.10

does somebody can help me to explain what is problem and how can I solve it, here is my model, it is a single wind turbine model, I use the conical shaped to be my compuataional domain, I set 3 periodic boundary condtions, one velocity inlet and pressure outlet, what's more, I set the top and the bottom of the concial shape as wall condition, inside the periodic 2, I want to use MRF to simulate the wind turbine rotate and hope this boundary condition is correct, Now, I stuck on this problem and could not move forward, looking for someone who can save me.
Attached Images
 4.jpg (48.5 KB, 39 views)

 May 21, 2010, 01:30 #2 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,160 Rep Power: 32 Is your mesh right connected? it seems you have more than one zone. Try to see if the "interfaces" between zones are wall or interior __________________ In memory of my friend Hervé: CFD engineer & freerider

May 21, 2010, 05:09
#3
Member

tom
Join Date: Feb 2010
Posts: 46
Rep Power: 8
Quote:
 Originally Posted by -mAx- Is your mesh right connected? it seems you have more than one zone. Try to see if the "interfaces" between zones are wall or interior
I got three volume in my model and beafore setting the periodic condition, I hard link the face which I thought it is right connected. So, do I need to set up the "interfaces" between two volumes as interior? I will try is first, then to see what will be happened
Attached Images
 4.jpg (49.8 KB, 13 views)

 May 21, 2010, 05:22 #4 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,160 Rep Power: 32 if your volumes are right connected, "interfaces" should be automatically set as interior (and invisible). to be sure just display the default "wall" BC, and check if you see any "interfaces" in this bc. You can also display wall_bottom:001 etc... to see where is your issue __________________ In memory of my friend Hervé: CFD engineer & freerider

May 21, 2010, 05:56
#5
Member

tom
Join Date: Feb 2010
Posts: 46
Rep Power: 8
Quote:
 Originally Posted by -mAx- if your volumes are right connected, "interfaces" should be automatically set as interior (and invisible). to be sure just display the default "wall" BC, and check if you see any "interfaces" in this bc. You can also display wall_bottom:001 etc... to see where is your issue
it seems my volume are incorrect, I post two picss, the first one is wall bottom 001, the second is wal bottom.
Attached Images
 5.jpg (103.8 KB, 16 views) 6.jpg (54.2 KB, 12 views)

 May 21, 2010, 06:49 #6 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,160 Rep Power: 32 try followings: *delete all your BC, except periodics and inlet-outlet (don't add any wall BC) *while exporting gambit should set the remaings surfaces (without BC) as wall *check if fluent separates wall as prior __________________ In memory of my friend Hervé: CFD engineer & freerider

May 21, 2010, 08:09
#7
Member

tom
Join Date: Feb 2010
Posts: 46
Rep Power: 8
Quote:
 Originally Posted by -mAx- try followings: *delete all your BC, except periodics and inlet-outlet (don't add any wall BC) *while exporting gambit should set the remaings surfaces (without BC) as wall *check if fluent separates wall as prior
Hi mAx,
Now, I simplify the model with two volume, by following your suggestion, I only set the velocity inlet,pressure outlet and periodic. improt the mesh to fluent, it give me a tip, here it is :

Note: Separating wall zone 8 into zones 8 and 1.
wall -> wall (8) and wall:001 (1)
Note: Separating interior zone 12 into zones 12 and 11.
default-interior -> default-interior (12) and default-interior:011 (11)
Note: Separating interior zone 12 into zones 12 and 13.
default-interior -> default-interior (12) and default-interior:013 (13)

periodic.2
Skipping zone periodic.2_shadow (not referenced by grid).
periodic.1
Skipping zone periodic.1_shadow (not referenced by grid).
Attached Images
 two volume.jpg (31.0 KB, 9 views) wall.jpg (76.5 KB, 9 views) wall 001.jpg (32.2 KB, 8 views) default-interior 011.jpg (8.8 KB, 7 views) default interior 013.jpg (6.2 KB, 5 views)

May 21, 2010, 08:13
#8
Member

tom
Join Date: Feb 2010
Posts: 46
Rep Power: 8
Quote:
 Originally Posted by -mAx- try followings: *delete all your BC, except periodics and inlet-outlet (don't add any wall BC) *while exporting gambit should set the remaings surfaces (without BC) as wall *check if fluent separates wall as prior
is it normal while fluent say: periodic.2 Skipping zone periodic.2_shadow (not referenced by grid). periodic.1 Skipping zone periodic.1_shadow (not referenced by grid). Beacuse I check the fluent tutorial about mixing plane method, it is a rotor and stator model. when I import the mesh, fluent also say (not reference grid)

 May 21, 2010, 08:29 #9 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,160 Rep Power: 32 ah.. rotor and stator, that's why you have 2 zones, ok. That means fluent separates BC which belong to both zones into BC (one BC for one zone) sorry... __________________ In memory of my friend Hervé: CFD engineer & freerider

May 21, 2010, 08:55
#10
Member

tom
Join Date: Feb 2010
Posts: 46
Rep Power: 8
Quote:
 Originally Posted by -mAx- ah.. rotor and stator, that's why you have 2 zones, ok. That means fluent separates BC which belong to both zones into BC (one BC for one zone) sorry...

May 21, 2013, 07:25
#11
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Join Date: Mar 2013
Posts: 48
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Quote:
 Originally Posted by -mAx- try followings: *delete all your BC, except periodics and inlet-outlet (don't add any wall BC) *while exporting gambit should set the remaings surfaces (without BC) as wall *check if fluent separates wall as prior
hi dear max
i,m simulating a wind turbine with a complete model(3 blades and one hub)
i have 3 zones
i had set the fluid around turbine as MRF and the others as stationary
i have 2 interfaces to join them and the other bc are as:
velocity inlet 11.4 m/s
pressure outlet 0 gauge
wind turbine moving wall relative to adjacent cell zone , 0
the fluent start iterating but when i display the velocity magnitude counters ,all velocity magnitudes are 0

would you plz help me???

 May 21, 2013, 08:18 #12 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,160 Rep Power: 32 I am not experienced with SRF or MRF, but I don't think you need any interface http://aerojet.engr.ucdavis.edu/flue...tg/node135.htm __________________ In memory of my friend Hervé: CFD engineer & freerider

May 21, 2013, 08:53
#13
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Join Date: Mar 2013
Posts: 48
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Quote:
 Originally Posted by -mAx- I am not experienced with SRF or MRF, but I don't think you need any interface http://aerojet.engr.ucdavis.edu/flue...tg/node135.htm

you mean it,s better to consider all zones as stationary or as rotating
or you mean using mixing plan or interior in stead of interfaces????

 May 21, 2013, 09:14 #14 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,160 Rep Power: 32 I mean, reconsider using interfaces. Instead of that, go to gambit (or your mesher) and reconnect both zones. That means no interfaces. You will still need to separate stationnary and rotor zone (as different fluid domains) I would check tutorial. The other way is to use sliding mesh, and in this case you need interfaces, since your rotor will rotate __________________ In memory of my friend Hervé: CFD engineer & freerider

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