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Old   December 15, 2012, 02:24
Default Periodic pressure gradient.
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A7A
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Hi,

I am modelling a 3d periodic flow of air in a tube with wire coil insert (using relizable k-e model), and after 1500 iterations i get a good results of Nusselt number compared to the experimental results, but the friction factor(which is computed this way: f=(dp)/(0.5*density*velocity^2*(length/tube diameter))
is so high compared to the experimental results.

Could you give me any advice about this problem.

Thank you in advance

Last edited by A7A; December 25, 2012 at 04:10.
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Old   December 15, 2012, 09:32
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Any ideas?
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Old   December 25, 2012, 04:13
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Could you give me any solutions, untill now i couldnt manage to solve this problem.

Thank you in advance.
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Old   January 15, 2013, 09:38
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Quote:
Originally Posted by A7A View Post
Could you give me any solutions, untill now i couldnt manage to solve this problem.

Thank you in advance.
Which value of dp do you use for calculation of f? the correct value should be the pressure gradient under the periodic boundaries panel, you have to multiply it by the length of your tube.
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Old   January 15, 2013, 11:27
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Thank you Kamu for your reply , but there is no need to multiply dp by tube length because its divided by length in f correlation.
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