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fundamental question about Lift Report and Integral Pressure

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Old   June 17, 2015, 02:56
Angry fundamental question about Lift Report and Integral Pressure
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farzadpourfattah
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Hello.
I simulate flow around a wing at angle of attack 0 degree and my pressure distributions is valid experiment result. BUT , when I compare lift force (Report>force>(0,1,0) ) with (Report>integral>static Pressure on wing),
I am confused! that why these value is differ together?
please help me.
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Old   June 17, 2015, 10:41
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Andrew Kokemoor
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The integral of pressure is a scalar, it has no direction. Integrating across the entire wing will sum together pressure contributions from all surfaces, regardless of direction.

The lift force is the pressure times the dot product of the face area vector and the direction vector you specify; pressure pushing down will cancel out with pressure pushing up, and pressure pushing to the side will not be affect the calculated force.
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Old   June 17, 2015, 13:14
Smile dear Kokemoor
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Thanks alot.You elucidate me about this.
I search in all document of Fluent software to find relation of computing lift force but I can't find,Can you guide me?
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Old   June 17, 2015, 14:00
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Andrew Kokemoor
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Check out the Fluent Theory Guide, Section 22.2.1. Computing Forces, Moments, and the Center of Pressure.
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