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Flow/ Velocity Calculation

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Old   November 19, 2012, 15:49
Default Flow/ Velocity Calculation
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Nikunj Raithatha
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Hello All!

As shown in the attached figure, I have fluid passing in positive and negative direction, through a plane. I was wondering, if there is a way to calculate the average flowrate (or even velocity) that is going in positive direction and negative direction separately.

In paraFoam, I tried using "integrateVariable" filter for this plane, but it is giving me integrated total velocity through this plane and not negative and positive values.

Any help in this regard will be greatly appreciated. Thanks for your time.


Regards,
Nikunj.
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Old   November 21, 2012, 19:19
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Quote:
Originally Posted by Nikunj.R View Post
Hello All!

As shown in the attached figure, I have fluid passing in positive and negative direction, through a plane. I was wondering, if there is a way to calculate the average flowrate (or even velocity) that is going in positive direction and negative direction separately.

In paraFoam, I tried using "integrateVariable" filter for this plane, but it is giving me integrated total velocity through this plane and not negative and positive values.

Any help in this regard will be greatly appreciated. Thanks for your time.


Regards,
Nikunj.
Something like (this is just a sketch, assumes that you're either on a faceSet, faceZone or sampledSurface)

Code:
variables (
    "upArea=sum(U.z>0 ? area() : 0);"
    "upVelSum=sum(U.z>0 ? U.z*area() : 0);"
);

expression "upVelSum/max(upArea,1e-15)";
in swak4Foam could do the trick.
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