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Old   May 17, 2013, 06:42
Default problem regarding validation
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Noorul Huda
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Hello..
i'm doing simulation on a pleated dragon fly wing Re=10000. My results are not matching with experimental results. the experimental Cl value is 0.27 and mine is coming out to be -0.05. my grid size is 0.0002 and time interval is 0.001.
my inlet conditions are v=1m/s and gauge pressure=0. my reference length is 1m. please me. tell me where i'm going wrong.
Thank you..
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Old   May 17, 2013, 07:16
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Lefteris
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Reference length should be the mean chord's length.
Has your problem converged?
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Old   May 17, 2013, 07:23
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Yes Sir it's a 2D airfoil with 1 unit length and my solution is statistically stable now
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Old   May 17, 2013, 08:14
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Statistically now... what? Did you lose interest while typing? lol

Which schemes have you employed?
What convergence criteria have you used?
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Old   May 17, 2013, 08:29
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Sir that was just a mistake
it's Statistically stationary.
Sir i'm using fractional step with and convergence criteria up to 1e-06 have achieved for velocities and 1e-05 for continuity. square domain of 60c/60c (c=chord length=1) have been used.
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Old   May 17, 2013, 08:48
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What's the angle of attack? Have you analysed the forces in the proper direction?
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Old   May 17, 2013, 09:05
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Yes, Sir my forces are in proper direction. The direction of force normal to the wing is in the upward direction and angle of attack is 0.
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Old   May 17, 2013, 09:11
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Uhm... right now I can't think of something else.. try to reduce your domain though. I think 60c x 60c is too large. Try making it 30c x 30c and improve the mesh as much as possible.
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Old   May 17, 2013, 09:16
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Alright Sir, but size is already too small (2e-04). Do you think that reducing the size furthur will affect my solutions..??
but i'll do whatever you have suggested me Sir. Thanks a lot for entertaining me. Please assist me in the future also, i may need you then..
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