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Old   January 25, 2008, 09:05
Default covective boundary condition
  #1
Mani
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Hi

What is convective boundary condition and how can i impose it? I am working on CFX 11. I am simulating a flow over an airfoil which must use covective boundary condition at the outlet. Thanks

Mani
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Old   January 25, 2008, 13:50
Default Re: covective boundary condition
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KYO
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If I am not wrong, convective BC is the same as the Neumann BC... look for it in google... good luck...
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Old   January 25, 2008, 16:38
Default Re: covective boundary condition
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Mani
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I have no idea what Neumann BC is but i think know now what convective BC is! Its more like an outlet BC. It is used to prevent any sound reflection back in domain. Thanks for reply.

Regards Usman
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Old   January 28, 2008, 06:39
Default Re: covective boundary condition
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sega
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In general the convective BC declares that heat flux normal to the boundary is given by this equation:

q_n = alpha (T_inf - T)

q_n: heat flux normal to the boundary; alpha: heat transfer coefficient (maybe give, or you get it from Nusselt-Equations, or maybe it your task to calculate it ...); T_inf: Temperature of the farfield; T: Temperature at the boudary

You wrote something about an outlet BC. An outlet BC must be a given velocity normal to the boundary. Like this:

u*n_x+v*n_y = constant

u: x-velocity; n_x: component of normal-vector in x-direction

Correct me if I'm wrong.

P.S. How can I do linebreak in this forum?
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Old   January 28, 2008, 18:24
Default Re: covective boundary condition
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Mani
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Why do you need to do line break in this forum. Are you working with LES sega.

Mani
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Old   January 28, 2008, 19:05
Default Re: covective boundary condition
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S. Gatzka
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What's LES?
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Old   January 28, 2008, 19:19
Default Re: covective boundary condition
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Mani
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Large Eddy Simulation is a superior technique to traditional RANS modelling. RANS modelling is crap, if you are still using it, give it up. LES is taking over!

Mani
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