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what should i do to have more accurate results for analysing the flow over a airfoil?

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Old   August 4, 2013, 04:40
Default what should i do to have more accurate results for analysing the flow over a airfoil?
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s.m
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saeideh mohamadi
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Hi, i want to have a more lower residual for my analysis, what should i do?

i also want to have a more accurate results, on slat pressure coeffient, what changes should i do in my setting of openfoam?
i attach the experiment pressure coefficient result and the pressure coefficient that is resulted from my simulation in the next thread. as you see i don't have an accurate result for my slat, what should i do?
Attached Images
File Type: jpg residual186.jpg (30.9 KB, 4 views)
File Type: jpg p.jpg (8.9 KB, 4 views)
File Type: jpg pp.jpg (14.8 KB, 4 views)
File Type: jpg u.jpg (16.2 KB, 3 views)
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Old   August 4, 2013, 04:52
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these are the experiment and my simulation result for pressure coefficient of slat and flap elements.
as you see i don't have accurate result for slat, and whan i change the turbulence model from kw-sst to RNGkEpsilon it become more inaccurate, why?
Attached Images
File Type: png cp-slat-experiment.png (16.7 KB, 5 views)
File Type: png my cp-slat-kwsst.png (24.7 KB, 5 views)
File Type: png cp-flap-experiment.png (16.3 KB, 3 views)
File Type: png my cp-flap-kwsst.png (16.7 KB, 2 views)
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Old   August 4, 2013, 04:58
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these are the experiment and my simulation result for pressure coefficient of main element.
as you see in 0 folder, i use freestream boundary condition for my simulation, this boundary give me more better result than the velocity inlet&pressure outlet.
Attached Images
File Type: png cp-main-experiment.png (14.4 KB, 1 views)
File Type: png my cp-main-kwsst.png (17.8 KB, 1 views)
Attached Files
File Type: txt fvSchemes.txt (3.4 KB, 4 views)
File Type: txt fvSolution.txt (4.2 KB, 2 views)
File Type: zip 0.zip (6.3 KB, 0 views)
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Old   August 4, 2013, 10:11
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change in fvSolution for atleast U and p to
Quote:
relTol 0.0;
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Old   August 5, 2013, 05:17
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Quote:
Originally Posted by nimasam View Post
change in fvSolution for atleast U and p to
Ok Dear nima, would you please explain the differences between tolerance and reTol in fvSolution ?
Thank you

as you see the reduction of my residuals are really low, especially for p, i'll do what you said, and attach the residual figure.
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Old   August 5, 2013, 05:40
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well

relTol is relative tolerance and tolerance is absolute one so it would be clear why relTol should be 0.0
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