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Switching on LES in 2D mode of fluent

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Old   February 17, 2003, 12:47
Default Switching on LES in 2D mode of fluent
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Josef Dubsky
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Can anybody tell me, how to switch on (activate, as desribed in tutorials) the LES in 2D mode of Fluent 6.0? In the tutorials for the new accoustic module it just sais: 1. Activate the LES turbulence model for 2D calculations (rpsetvar 'les-2d? #t)

2. Select the Large Eddy Simulation turbulence model.

Define -> Models -> Viscous...........

Thank you very much

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Old   February 18, 2003, 04:38
Default Re: Switching on LES in 2D mode of fluent
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ff
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Just write (rpsetvar 'les-2d? #t), as it say, in your text interface(Plus "return").

Regards

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Old   February 18, 2003, 05:31
Default Re: Switching on LES in 2D mode of fluent
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Josef Dubsky
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I am sorry, I am just a new user of Fluent - I have already tried to write this command in the command line in Fluent before I posted my question to this forum, but I always get message saying "invalid command [(rpsetvar]". Maybe I am doing something wrong - I am just getting used to using Fluent now.
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Old   February 18, 2003, 05:43
Default Re: Switching on LES in 2D mode of fluent
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Josef Dubsky
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Perfect, I have already managed to go through this. I could not believe it.If you copy this command from the help and paste it in the command line, it does not work, but if you type it - EXACTLY THE SAME - and press enter again, it works. I do not know, what difference it makes, whether you copy the text or type it yourself, but the copy method simply does not work
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Old   August 27, 2012, 07:41
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Quote:
Originally Posted by Josef Dubsky
;104505
Perfect, I have already managed to go through this. I could not believe it.If you copy this command from the help and paste it in the command line, it does not work, but if you type it - EXACTLY THE SAME - and press enter again, it works. I do not know, what difference it makes, whether you copy the text or type it yourself, but the copy method simply does not work
Thanks

Last edited by nimbus1947; August 29, 2012 at 02:05.
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Old   July 14, 2013, 14:34
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Quote:
Originally Posted by Josef Dubsky
;104495
Can anybody tell me, how to switch on (activate, as desribed in tutorials) the LES in 2D mode of Fluent 6.0? In the tutorials for the new accoustic module it just sais: 1. Activate the LES turbulence model for 2D calculations (rpsetvar 'les-2d? #t)

2. Select the Large Eddy Simulation turbulence model.

Define -> Models -> Viscous...........

Thank you very much
hello
I think you have just to type the following message (with parenthesis) in the console window of fluent and it will work:
>(rpsetvar `les-2d? #t)
there is just a trick in the apostrophe : type AltGr + 7 and then to see the apostrophe type the next letter "l".good luck
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Old   September 14, 2013, 11:23
Default 2d-LES starting
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I am using the command (rpsetvar 'les-2d? #t)
the following message comes in dialog box
Error: rp-var-value-set!: undefined variable
Error Object: 2d-les?

can anybody help. does my system should have visual studio then only it will work

Regards
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Old   December 10, 2013, 07:15
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Goutam Saha
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Quote:
Originally Posted by pitamber.methia View Post
I am using the command (rpsetvar 'les-2d? #t)
the following message comes in dialog box
Error: rp-var-value-set!: undefined variable
Error Object: 2d-les?

can anybody help. does my system should have visual studio then only it will work

Regards
I wrote this command (rpsetvar 'les-2d? #t)
and LES is activated. But only problem is, if you run LES, you will never get unsteady statistics (mean and rms) in 2D case. So, it will not helpful and it's better to use LES in 3D.
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Old   April 30, 2014, 01:20
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Quote:
Originally Posted by Goutam View Post
I wrote this command (rpsetvar 'les-2d? #t)
and LES is activated. But only problem is, if you run LES, you will never get unsteady statistics (mean and rms) in 2D case. So, it will not helpful and it's better to use LES in 3D.
Thanks Gautam. Does using axis symmetric condition will be same as 3d
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Old   April 30, 2014, 06:29
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Quote:
Originally Posted by pitamber.methia View Post
Thanks Gautam. Does using axis symmetric condition will be same as 3d
I used 2D axi-symmetric case. I found that unsteady RANS models perform better than LES. LES tooks long time to converge and I will suggest you to use 3D geometry when using LES. It will give you better accuracy.
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Old   May 1, 2014, 04:56
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Lucky Tran
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Quote:
Originally Posted by pitamber.methia View Post
Thanks Gautam. Does using axis symmetric condition will be same as 3d
LES in 2D is highly non-physical. Same goes for 3D LES with any type of symmetry conditions. Using LES in either of these circumstances should be avoided. If you choose to do it anyway, then be ready for wildly different results.

On the other hand, 2D / 3D RANS should yield same results.

Last edited by LuckyTran; May 1, 2014 at 12:30.
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Old   May 1, 2014, 10:41
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As LuckyTran stated before, because turbulence is a 3D physical phenomenon (e.g. vortex stretching is impossible in two dimensions), you are not going to get sensible results from a 2D (or axisymmetric) LES calculation
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