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Old   July 13, 2013, 17:12
Question total pressure at inlet
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hi experts.
i'm simulating a rectangular channel with a weir which is placed in the middle of channel. I want to set inlet BC to total pressure. the flow is free surface and I now the total pressure but I don't know the depth of water at the inlet. discharge is also known. how can I set the volume fraction at the inlet?
thanks in advance.
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Old   July 13, 2013, 18:44
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If you do not know the depth at the inlet then how can you know the inlet pressure? You cannot account for the hydrostatic component.
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Old   July 14, 2013, 02:55
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Quote:
Originally Posted by ghorrocks View Post
If you do not know the depth at the inlet then how can you know the inlet pressure? You cannot account for the hydrostatic component.
the total pressure is in the form of pisometric head. it comes from experimental date. it is possible to measure total head consist of velocity head and static pressure head.
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Old   July 14, 2013, 06:21
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Can you show an image of it?

But if this means your inlet is at a region where the flow has a significant velocity and a free surface, then it will probably be easiest to draw a chamber upstream to have the fluid entering at the correct height at zero pressure, and as a single phase. This will generate the exact conditions you want without numerical difficulties - but at the price of some extra mesh elements.
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Old   July 17, 2013, 17:26
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thanks a lot.
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