Axysimmetric cases compare to planar case with symmetry boundary condition

hafiidz · June 7, 2011, 08:40

Hi guys,

I am trying to run an 2D axisymmetric underexpanded jet fire using fluent. However, to simpify the case we use the pseudo diameter approach and focus just on the visible length of the flame ( the shock waves are being excluded).

I created my mesh using Gambit. setting it up to be an axisymmetric case. However, when I exported it to Fluent, I can't run it with the BC that i have set in Gambit as I can't initialize it. But when I changed it to planar cases and the axis to symmetry, it can be initialized.

I hope someone can point me what's the difference between these two settings and how can I overcome it.

Thank you.

meangreen · June 8, 2011, 14:40

A few questions:

what version of fluent are you using?
Is it a cracked version or do you have a license?
When you make your mesh in gambit to you export it as a 2D mesh?

Are you going into define-models (i think that is the way, my fluent is down for a little while) and setting the solver to axisymmetric?

xrs333 · June 8, 2011, 18:46

Hi, jaafar,
For axisymmetric model, it is necessary that the axis must be X axis and the grid above X axis.

hafiidz · June 9, 2011, 04:17

meangreen

I am using fluent 12 and 13. Both of them are with license. I exported it with 2d mesh as well. I have defined it in the general part in FLUENT.

xrs333

I see. i will try that. Anyway, is there any differences of result between axisymmetric model and setting a planar model with symmetry boundary condition.

thank you for the reply guys.

xrs333 · June 9, 2011, 11:26

Hi, Jaafar,
They are absolutely different.

hafiidz · June 14, 2011, 07:29

Thank you for your reply.

June 7, 2011, 08:40	Axysimmetric cases compare to planar case with symmetry boundary condition	#1
hafiidz New Member hafiidz jaafar Join Date: Jun 2010 Posts: 4 Rep Power: 16	Hi guys, I am trying to run an 2D axisymmetric underexpanded jet fire using fluent. However, to simpify the case we use the pseudo diameter approach and focus just on the visible length of the flame ( the shock waves are being excluded). I created my mesh using Gambit. setting it up to be an axisymmetric case. However, when I exported it to Fluent, I can't run it with the BC that i have set in Gambit as I can't initialize it. But when I changed it to planar cases and the axis to symmetry, it can be initialized. I hope someone can point me what's the difference between these two settings and how can I overcome it. Thank you.

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June 8, 2011, 14:40		#2
meangreen Member Casey Join Date: Jun 2009 Posts: 98 Rep Power: 17	A few questions: what version of fluent are you using? Is it a cracked version or do you have a license? When you make your mesh in gambit to you export it as a 2D mesh? Are you going into define-models (i think that is the way, my fluent is down for a little while) and setting the solver to axisymmetric?

June 8, 2011, 18:46		#3
xrs333 Senior Member xrs333 Join Date: Aug 2010 Posts: 125 Rep Power: 17	Hi, jaafar, For axisymmetric model, it is necessary that the axis must be X axis and the grid above X axis.

June 9, 2011, 04:17		#4
hafiidz New Member hafiidz jaafar Join Date: Jun 2010 Posts: 4 Rep Power: 16	meangreen I am using fluent 12 and 13. Both of them are with license. I exported it with 2d mesh as well. I have defined it in the general part in FLUENT. xrs333 I see. i will try that. Anyway, is there any differences of result between axisymmetric model and setting a planar model with symmetry boundary condition. thank you for the reply guys.

June 9, 2011, 11:26		#5
xrs333 Senior Member xrs333 Join Date: Aug 2010 Posts: 125 Rep Power: 17	Hi, Jaafar, They are absolutely different.

June 14, 2011, 07:29		#6
hafiidz New Member hafiidz jaafar Join Date: Jun 2010 Posts: 4 Rep Power: 16	Thank you for your reply.