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How model natural convection in water?

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Old   January 27, 2010, 10:45
Default How model natural convection in water?
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Daniele
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Hi! I'm modeling a problem of natural convection induced by a thermal source. Fluid is water. I've already set 'Density' as 'boussinesq', 'Thermal Expansion Coefficient' is 1/T, (where T is T of film). It seems that everything si right, but the output is not satisfactionary. Why?
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Old   January 27, 2010, 10:59
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*satisfactorily, excuse the mistake! BC are all costant temperatures, there's a heat source in the centre, and the flow il laminar. Thank you sincerely for the help you will be able to give me.
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Old   January 27, 2010, 12:18
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I need your advice. Is there somebody who could answer to me?
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Old   January 27, 2010, 13:58
Default boussinessq hyp
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Hi,
try using different function for rho(T) for water....1/T settings may just not be right for water. when pv = rho*R*T, you can easily derive expansion coefficient = 1/T but thats for gases..for water, the expansion is much lower.

try searching for water thermal expansion coefficient and validate the code with some known results first and then experiment for different beta.

/CFDtoy

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I need your advice. Is there somebody who could answer to me?
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Old   January 28, 2010, 04:23
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Hi! Thank you very much for your suggestion. I think that I'll set the density as 'piecewise polynomial'.. Have a nice CFDay!!
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