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local and average Nusselt number

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Old   May 12, 2013, 04:18
Default local and average Nusselt number
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Ali
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Hi everyone

I have problem to obtain the local and average Nusselt number around square cylinder.
Temperature distribution around the cylinder is achieved.
I'm not sure about dimensionless temperature.
which length should be used as characteristic length
what should i do?

Thanks
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Old   May 12, 2013, 07:42
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Filippo Maria Denaro
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q= - k Grad T -> q L/k(Tr - T0) = - Grad* T*

Nu = |q|L/k(Tr - T0)

and L is the same characteristic lenght used for defining the non-dimensional form of the continuity, momentume and energy equations
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Old   May 12, 2013, 08:36
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Quote:
Originally Posted by FMDenaro View Post
q= - k Grad T -> q L/k(Tr - T0) = - Grad* T*

Nu = |q|L/k(Tr - T0)

and L is the same characteristic lenght used for defining the non-dimensional form of the continuity, momentume and energy equations
Thanks dear Filippo

but temperature at solid surface of the cylinder is constant.
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Old   May 12, 2013, 08:51
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Quote:
Originally Posted by PPPO View Post
Thanks dear Filippo

but temperature at solid surface of the cylinder is constant.
but you have to consider the normal derivative of the temperature ...
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