[GAMBIT] is it possible to create this type of grid?

ghost82 · January 4, 2012, 11:55

Hi all,
is it possible in Gambit to create this type of grid (attached picture)?If yes, how?

Thank you,

Daniele

Far · January 4, 2012, 12:23

yes it can be done in gambit. but you need to make them in steps and then import into fluent and then create the interfaces. However this can be easily done in icem cfd by refining the domains by the factor of 2 and you have two nodes corresponding to one node to other side.

BigBen · January 4, 2012, 18:12

I confirm, it can be easliy done in Gambit but as said, you need to disconnect faces where the mesh is not conformed in Gambit and create interface in Fluent.

I may have another possibility. I would rather do everythng in Fluent using the Adapt/Region/refine in 3 steps.
Firts of all, create your mesh in gambit with the coarser mesh and import in Fluent.
In Fluent
1-adapt/region select by coordinates or by mouse button all the region which is refined (all the upper rectangular even the more refined). Press "refine" it will multiply by two the mesh in this region.
2-3 do it again for the small square on the upper left and upper right.

Hope it will help

Far · January 4, 2012, 21:28

Yeah it is much better and easier method and does not require interfaces

ghost82 · January 5, 2012, 10:07

Quote:

Originally Posted by BigBen

I confirm, it can be easliy done in Gambit but as said, you need to disconnect faces where the mesh is not conformed in Gambit and create interface in Fluent.

I may have another possibility. I would rather do everythng in Fluent using the Adapt/Region/refine in 3 steps.
Firts of all, create your mesh in gambit with the coarser mesh and import in Fluent.
In Fluent
1-adapt/region select by coordinates or by mouse button all the region which is refined (all the upper rectangular even the more refined). Press "refine" it will multiply by two the mesh in this region.
2-3 do it again for the small square on the upper left and upper right.

Hope it will help

Thank you Bigben,
I knew that this could be done in fluent; however I was curious to know if that grid could be done directly in gambit.
Thank you all for replies.

Daniele

themeska · February 3, 2012, 04:55

Hi everybody!

I think this is the thread i've been looking for...as you all said a local refinement is possible and even easier in Fluent, by using the Adapt panel...anyway, this wouldn't be the easiest way for my geometry, since it consists of buildings with different heights...
Everytime i try to vertically sweep the outer region (which is to time as coarse as the inner one), Gambit says it cannot sweep it...i think it's because of the different number of intervals between the inner and outer region...and maybe Gambit is not able to connect them, am i saying something wrong?

can anyone explain to me how to do that?

What i'd like to do is to impose in Fluent different BCs for the inlet flow (i mean, different roughness heights), using different values for the inner and outer region...

Far · February 3, 2012, 10:03

Quote:

Everytime i try to vertically sweep the outer region (which is to time as coarse as the inner one), Gambit says it cannot sweep it...i think it's because of the different number of intervals between the inner and outer region...and maybe Gambit is not able to connect them, am i saying something wrong?

In mapping you cannot just change the nodes on one edge, you should change the no of nodes on parallel edges, but if you to make the mesh shown in 1st post, then you need to create different regions and save in different files and keep the region which you want to mesh and delete all other. Then export the mesh from all these files and read them in Fluent with append command. Got it?

themeska · February 3, 2012, 10:10

So, basically, what you're saying is that i should create as many meshes as the regions with different cells' sizes and then "put" them together in Fluent?

Thanks a lot for your fast reply, helped a lot!
Regards

Far · February 3, 2012, 10:22

yes and at the common boundaries specify interface as boundary condition.

You muest read first mesh and for other meshes you must use the append command.

January 4, 2012, 12:23		#2
Far Super Moderator Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54	yes it can be done in gambit. but you need to make them in steps and then import into fluent and then create the interfaces. However this can be easily done in icem cfd by refining the domains by the factor of 2 and you have two nodes corresponding to one node to other side. ghost82 likes this.

January 4, 2012, 18:12		#3
BigBen New Member Join Date: Dec 2011 Posts: 10 Rep Power: 14	I confirm, it can be easliy done in Gambit but as said, you need to disconnect faces where the mesh is not conformed in Gambit and create interface in Fluent. I may have another possibility. I would rather do everythng in Fluent using the Adapt/Region/refine in 3 steps. Firts of all, create your mesh in gambit with the coarser mesh and import in Fluent. In Fluent 1-adapt/region select by coordinates or by mouse button all the region which is refined (all the upper rectangular even the more refined). Press "refine" it will multiply by two the mesh in this region. 2-3 do it again for the small square on the upper left and upper right. Hope it will help ghost82 likes this.

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January 4, 2012, 21:28		#4
Far Super Moderator Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54	Yeah it is much better and easier method and does not require interfaces

February 3, 2012, 04:55		#6
themeska New Member Davide Join Date: Jan 2012 Posts: 2 Rep Power: 0	Hi everybody! I think this is the thread i've been looking for...as you all said a local refinement is possible and even easier in Fluent, by using the Adapt panel...anyway, this wouldn't be the easiest way for my geometry, since it consists of buildings with different heights... Everytime i try to vertically sweep the outer region (which is to time as coarse as the inner one), Gambit says it cannot sweep it...i think it's because of the different number of intervals between the inner and outer region...and maybe Gambit is not able to connect them, am i saying something wrong? can anyone explain to me how to do that? What i'd like to do is to impose in Fluent different BCs for the inlet flow (i mean, different roughness heights), using different values for the inner and outer region...

February 3, 2012, 10:10		#8
themeska New Member Davide Join Date: Jan 2012 Posts: 2 Rep Power: 0	So, basically, what you're saying is that i should create as many meshes as the regions with different cells' sizes and then "put" them together in Fluent? Thanks a lot for your fast reply, helped a lot! Regards

February 3, 2012, 10:22		#9
Far Super Moderator Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54	yes and at the common boundaries specify interface as boundary condition. You muest read first mesh and for other meshes you must use the append command.