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May 17, 2013, 06:42 |
problem regarding validation
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#1 |
New Member
Noorul Huda
Join Date: Dec 2012
Location: Aligarh, UP India
Posts: 13
Rep Power: 13 |
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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May 17, 2013, 07:16 |
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#2 |
Senior Member
Lefteris
Join Date: Oct 2011
Location: UK
Posts: 337
Rep Power: 15 |
Reference length should be the mean chord's length.
Has your problem converged?
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Lefteris |
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May 17, 2013, 07:23 |
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#3 |
New Member
Noorul Huda
Join Date: Dec 2012
Location: Aligarh, UP India
Posts: 13
Rep Power: 13 |
Yes Sir it's a 2D airfoil with 1 unit length and my solution is statistically stable now
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May 17, 2013, 08:14 |
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#4 |
Senior Member
Lefteris
Join Date: Oct 2011
Location: UK
Posts: 337
Rep Power: 15 |
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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Lefteris |
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May 17, 2013, 08:29 |
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#5 |
New Member
Noorul Huda
Join Date: Dec 2012
Location: Aligarh, UP India
Posts: 13
Rep Power: 13 |
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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May 17, 2013, 08:48 |
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#6 |
Senior Member
Lefteris
Join Date: Oct 2011
Location: UK
Posts: 337
Rep Power: 15 |
What's the angle of attack? Have you analysed the forces in the proper direction?
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Lefteris |
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May 17, 2013, 09:05 |
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#7 |
New Member
Noorul Huda
Join Date: Dec 2012
Location: Aligarh, UP India
Posts: 13
Rep Power: 13 |
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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May 17, 2013, 09:11 |
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#8 |
Senior Member
Lefteris
Join Date: Oct 2011
Location: UK
Posts: 337
Rep Power: 15 |
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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Lefteris |
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May 17, 2013, 09:16 |
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#9 |
New Member
Noorul Huda
Join Date: Dec 2012
Location: Aligarh, UP India
Posts: 13
Rep Power: 13 |
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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