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Wrong Result from Simulation...using Autodesk Project Falcon..

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Old   March 1, 2013, 12:53
Post Wrong Result from Simulation...using Autodesk Project Falcon..
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adi
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What is Fd stand for in FALCON result? And if it is drag force then why am i getting lower drag force via calculation by using same coefficient of drag as shown in falcon.I m getting Cd approx 1.22 on a block of 1 m^2 cross section at the speed of 10m/s. then how it is possible that drag force calculated by the falcon is 83.189 N?? (Attached Photo)
While I am using formula for drag force .5*Cd*(rheo)*A*V^2 then i am getting 74.725 N (assuming the density of air 1.225 kg/m^3)...plz help if u can its really important for my project...or suggest me any alternative way...

Thanks & Regards..
ADDY
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Old   March 1, 2013, 14:47
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We cant say completely wrong solution, actually theoretically most of the time cfd dont give "exact" solutions.
And there is and error about %11 not %50 or something because of this you should try different mesh size and check the mesh quailty and later then you can change your flow model.

Try these things and see the changes.. may be you take more approximate solution. ;(%5 or something this is your decision actually)
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Old   March 4, 2013, 04:20
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You should not expect to get better results from simulations. Maybe for some special artificial cases, but not for general ones.
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Old   March 4, 2013, 06:41
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Quote:
Originally Posted by addy01 View Post
What is Fd stand for in FALCON result? And if it is drag force then why am i getting lower drag force via calculation by using same coefficient of drag as shown in falcon.I m getting Cd approx 1.22 on a block of 1 m^2 cross section at the speed of 10m/s. then how it is possible that drag force calculated by the falcon is 83.189 N?? (Attached Photo)
While I am using formula for drag force .5*Cd*(rheo)*A*V^2 then i am getting 74.725 N (assuming the density of air 1.225 kg/m^3)...plz help if u can its really important for my project...or suggest me any alternative way...

Thanks & Regards..
ADDY
This appears to be a question for FALCON support or perhaps reading the FALCON manual. It would be rather surprising if the software writes a derived value on the screen without explaining how that value is derived.
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