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Old   May 2, 2012, 17:38
Default air under hull
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laurentL
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Hi,
i am a new NUMECA user. in a simulation of a high speed boat, it look like air going under the hull. what is the influences parameters to limite this effect.
thank you by advance for answers LL
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Old   May 2, 2012, 18:38
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laurentL
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sorry for disturbing,
the answer is in the documentation...
increase orthogonality, longer acceleration, CiStreakCorrection_YES; uwCiCorrection_YES
better question will be for a next time!!!
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Old   February 4, 2013, 23:07
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my actual problem is that coeficents, make the solution unstable... and so the results non available...
is there another solutions???
thank you for answering
LL
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Old   February 13, 2013, 21:42
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KHB
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Hi, been trying NUMECA for a while for high speed boat simulation also.
As you said I did notice that the uwCiCorrection_YES makes the solution more unstable for me. The CiStreakCorrection_Yes is better though..

Btw, are you running the full unsteady or the quasi-static analysis?
What is your Fn (by wetted length) that you are simulating?
What is the y+ of your hull? If it is too small, try to increase it, I suspect the air entrapment is due to AR of the cells near the interface is too big and/or the mesh is not refined enough..
Increasing orthogonality / refining the mesh helps but CPU cost will increase a lot!

Anyone has a suggestion?
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Old   February 18, 2013, 10:27
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laurentL
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Hi,
i found a solution, you must adjust the uwCorretionCoef_ in the line just under uwCiCorrection_YES!
for my case 0.3 was not enough but with 0.8 i had some good results. look at the pressure repartition on hull with this coef, it much better!
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