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problem with cl and cd coeffients

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Old   August 21, 2012, 08:17
Default problem with cl and cd coeffients
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nauman hashmi
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hi i am doing a CFD analysis of blended wing body fuselage. i am facing problems in calculation of Cl and Cd of the fuselage. my cl and cd ratio at many angle of attack (up to 36 deg) are around 3. i am using the projected area along z axis for calculation and my geometry is in YZ plane. my all dimension are in meters. i am conducting analysis at mach 0.8 and 30000 feet altitude. need urgent guidance on this regard.
thanks
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Old   August 21, 2012, 08:40
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my analysis is 3d and i m using SA model for the analysis.
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Old   August 22, 2012, 02:29
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Quote:
Originally Posted by nauman55 View Post
my analysis is 3d and i m using SA model for the analysis.
what problem you are facing? Your Cl and Cd values are not close to experimental values?
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Old   August 22, 2012, 02:55
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no sir they are not matching with the wind tunnel test. like i am gettting Cl value of 0.35 and cd around 0.05. which i think are not correct.
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Old   August 22, 2012, 03:05
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sir the cl /cd ratio is around 3 at different angle of attacks. it is just a lifting fuselage not with out wings. moreover the cd calculated by fluent is total cd or some sub set of Cd?
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Old   August 22, 2012, 07:12
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check if ur CV is big enough...
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Old   August 22, 2012, 07:41
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Originally Posted by nauman55 View Post
no sir they are not matching with the wind tunnel test. like i am gettting Cl value of 0.35 and cd around 0.05. which i think are not correct.
regards
what are the experimental values of Cl and Cd?
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moreover the cd calculated by fluent is total cd or some sub set of Cd?
Its total Cd
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