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Old   May 12, 2008, 11:38
Default turbulence viscosity ratio limited to ........
  #1
bbb
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hi all,

i am trying to model a wing in free air using k-e model. initially there is meaasge for turbulence viscosity ratio limited to 10e5 and eventually the iterations are terminated with AMG divergence : pressure corrections message. any help ?

thankyou

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Old   May 13, 2008, 14:33
Default Re: turbulence viscosity ratio limited to ........
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Meghnath
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hi,

if you are using fluent 6.3.26 version, change pressure cycle to flexible. To change this, goto solve-->multigrid.

M!
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Old   May 14, 2008, 09:02
Default Re: turbulence viscosity ratio limited to ........
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bbb
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hi, thankyou very much i will try this just now.

regards
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Old   May 16, 2008, 04:47
Default Re: turbulence viscosity ratio limited to ........
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bbb
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hi, i tried changing the change pressure cycle to flexible. i never got the amg divergence message but on the other hand number of cells in which the turbulnce viscosity ratio was limited to 10e5 kept increasing and the solution never converged with silly forces.

any help?

regards

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Old   May 16, 2008, 16:04
Default Re: turbulence viscosity ratio limited to ........
  #5
Meghnath
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hi

you can try following

1 Give temperature dependent laminar viscosity because if you are analysing gases, lam viscosity will increase with temperature, which will reduce viscosity ratio

2 Patch viscosity ratio < 1e5 in complete domain and run

Initially, number of cells with vis ratio limited to 1e5 will increase but later it will strat desreasing

M!
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Old   May 31, 2008, 10:07
Default Re: turbulence viscosity ratio limited to ........
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bbb
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hi, thankyou for the reply. can you please tell me where to do the changes in fluent ( i could not find ).

bbb

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Old   June 10, 2008, 08:49
Default Re: turbulence viscosity ratio limited to ........
  #7
Rakesh Jha
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Controls-limits
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