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Old   August 10, 2012, 15:00
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Hi dear friends
l have an important problem about fluent in modeling a spillway.in results i see negative pressure which is not correct.as a matter of fact,pressure must be positive.on slope,pressure must begin with positive mesure and change along the spillwau.but in my results ,pressure begins with negative mesure.i don't know what the problem is!
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Old   August 10, 2012, 17:17
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When you select Pressure, select also Absolute pressure instead of Static Pressure which is chosen by default
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Old   August 11, 2012, 13:20
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Thanks
I try that.but it doesn't work.pressure is still negative.the velocity measures are correct.do you think modeling in gambit is wrong?or is there any special setting in fluent which is effective?
Thank you very much
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Old   August 11, 2012, 13:46
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I don't think it's about the mesh. How did you set your boundary conditions specially for pressure and your Operating Conditions?
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Old   August 11, 2012, 14:05
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For example:in a simple model consist of a simple slope,i use :
Velocity inlet as input
pressure out let as output
Symetry
Wall.
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Old   August 11, 2012, 14:10
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Operating pressure is 101325
And also i apply variable density parameter 1.225
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Old   August 13, 2012, 03:46
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To know the reason, you may check these in sequence.
-pressure outlet is the same as you set.
-pressure drop between inlet and outlet is reasonable.
if this result is available, you then check your simplification model. Maybe there some different between the real model and the simulation model
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