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Periodic pressure gradient monitor in CFX

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Old   April 4, 2010, 05:59
Default Periodic pressure gradient monitor in CFX
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Luke
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Hello.

Is there a way to monitor the periodic pressure gradient in CFX as there is in Fluent (i.e. Monitors -> statistic-> per/ pr-grad)? I'm modeling flow through open cell metal foams in terms of microscopic approach in Fluent and I want to switch to CFX, but I can't find the way to enable such monitor (I searched in CFX manual, but there is no explanation how to do this) so I don't know how the results are correct in comparison with the results from Fluent. Can someone explain what to do, to enable/ create such periodic pressure gradient monitor?

Thank You. Best regards.

Luke
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Old   April 4, 2010, 08:30
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Glenn Horrocks
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Hopefully you should be able to do this easily. Define a CEL expression something like areaAve(p)@inlet - areaAve(p)@outlet and send it to a monitor point. Then you can monitor the pressure difference as the simulation progresses.
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Old   April 4, 2010, 13:51
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Hi ghorrocks. Thank You for Your quick reply.

But the problem is that I'm modeling a fluid flow through a single cell of metal foam. The periodic boundary condition is in the direction of the flow (transitional periodicity; inlet -> outlet). Simple substracting the pressure values will give me the difference in the lenght of a single cell (diameter: 1,8e-3 m) in [Pa]. I need to know the gradient in [Pa/m]. In CFX-Post, in the Variables tab, there is a pressure gradient variable that I can report, but it gives me a range of values and I need a specific (single) value. Any idea how to set such monitor?

Regards.

Luke
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Old   April 5, 2010, 09:22
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What about an expression like (areaAve(p)@inlet - areaAve(p)@outlet)/1.83e-3 [m]

The pressure gradient variable in CFD-Post is the gradient of the pressure field. Obviously this is another variable field and so is not what you want.
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Old   April 5, 2010, 15:56
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Thank You very much Glenn! It did the trick You're my hero(-ine)

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