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Boundary condition including time derivative

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Old   June 20, 2015, 11:35
Default Boundary condition including time derivative
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Ender Demirel
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Hello OF users,
I want to implement a Neumann type boundary condition for the pressure as follows

dp/dx=-p-dp/dt.

Does anyody know how to use this bc in OpenFoam or swak4Foam?
Best regards,
Ender
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Old   June 20, 2015, 11:37
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This is a fixed gradient BC
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Old   June 20, 2015, 11:44
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Quote:
Originally Posted by zfaraday View Post
This is a fixed gradient BC
Boundary condition depends on the first order time derivative of the pressure. I don't know how to use this time derivative term in the expression.
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Old   June 20, 2015, 15:02
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Forget about what I said in the last post, fixedGradient can't be used to suit your needs, I missunderstood the term Neumann you used... However, it can be achieved by using swak4foam and using the value for pressure from the last time step and the current one.

Best regards,

Alex
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