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Boundary Integration factor of 1000 different

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Hi,

If I perform a boundary integration through the PostProcessing > Boundary Integration menu on an outlet velocity, v, I get -2.428152e-9 [L/s]. Then if I then goto Options > Integration Couplings > Boundary Variables and enter VolFlow as the Name, v as the Expression and 4 as the Integration Order. Then in Global Expressions I create a variable called VolF which equals VolFlow.

I run the simulation and perform a boundary integration using the first method the result is -2.428152e-9 [L/s]. If I then look at the value of VolFlow from the PostProcessing > Global Variables VolF = -2.428152e-12

Why is there a factor of 1000 difference?

Regards,
Tom

1 Reply Last Post Aug 31, 2009, 4:09 p.m. EDT

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Posted: 1 decade ago Aug 31, 2009, 4:09 p.m. EDT
it could be because 1000 Liters = 1 m^3. The default unit system is SI so your boundary integration result for volumetric flow rate would be in m^3/s which is 1/1000 of flow rate in L/s
it could be because 1000 Liters = 1 m^3. The default unit system is SI so your boundary integration result for volumetric flow rate would be in m^3/s which is 1/1000 of flow rate in L/s

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