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Old   September 6, 2012, 22:52
Question Pressure-Inlet Boundary Condition
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M
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Hi Guys,

Considering a natural Convection problem (Steady State, Pressure-Based).I wonder if anyone knows what is the best value of the following factors in Pressure-Inlet Boundary Condition for Air at 20° C in a box with ∆T = 10° C ( T top –T bottom) at.

• Turbulent Intensity
• Turbulent Viscosity Ratio

OR

What is best value for K and Ɛ ?
Cheers,
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Old   September 7, 2012, 07:28
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Quote:
Originally Posted by Ariya View Post
Hi Guys,

Considering a natural Convection problem (Steady State, Pressure-Based).I wonder if anyone knows what is the best value of the following factors in Pressure-Inlet Boundary Condition for Air at 20° C in a box with ∆T = 10° C ( T top –T bottom) at.

• Turbulent Intensity
• Turbulent Viscosity Ratio

OR

What is best value for K and Ɛ ?
Cheers,
it is difficult to compute,because you could not know I and Re,so you can assume the average velocity(4e-4) and I(4%).by computing,we could define K and Ɛ!
of course ,it takes many time to verify!
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Old   September 7, 2012, 11:02
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It does not have to be exact. You can also use the option of intensity and hydraulic diameter.
For intensity you can mention 5% for the not highly turbulent flow (guess on the basis of upstrem condition of flow domain) and 10% for highly turbulent flow.

You can easily compute the hydraulic diameter based from the geometry features,
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Old   September 20, 2012, 01:17
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Thanks So much guys, your solotions are reaseonble and worked for me
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