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Periodic boundaries and pressure drop

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Old   July 11, 2005, 09:41
Default Periodic boundaries and pressure drop
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I ran a simple test case, 2D periodic pipe flow (symmetry on front and back, wall on left and right, 1:1 periodic interface on inlet and outlet, simple laminar flow -- so everything should be in order).. I applied a small momentum source to drive the flow -- this should define pressure drop per unit length.

However in results inlet and outlet have the same, or nearly the same, pressure (there is not any pressure drop!!, altough velocity is nonzero). In any case the pressure drop is not even near (it is way too small) to the one prescribed through momentum source.

What is happening?

there was a similar post in the past, but the issue has not been answered

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Old   July 11, 2005, 10:43
Default Re: Periodic boundaries and pressure drop
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I don't work with Periodic boundaries, but if you define your inlet and outlet as periodic interface, doesn't it mean that all variables values (including pressure) will be the same at inlet as at outlet?

I suppose that with this simulation will find what is the velocity field wich corresponds to a pressure drop equivalent to the momentum source.

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Old   July 12, 2005, 04:47
Default Re: Periodic boundaries and pressure drop
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Hi Rui,

ok, I see.. So, the solver prescribes the same pressure on inlet and outlet periodic faces, but the actual pressure on the outlet face is inlet pressure - momentum source*length of section

Thank you for clarifying this
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