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-   -   Low Reynolds Airfoil Modeling In Fluent (http://www.cfd-online.com/Forums/main/93671-low-reynolds-airfoil-modeling-fluent.html)

morteza08 October 23, 2011 09:49

Low Reynolds Airfoil Modeling In Fluent
 
Hi. I am modeling anderson Spica airfoil in fluent.
the maximum velocity is 40m/s.
the Grid is CH
what is the best boundary condition for inlet outlet and upper and lower boundary.
which solver can predict the cl and cd more accurate.
what about under-relaxation factors? discretization methods and pressure velocity coupling?
I did not get good result by my own settings.
the residuals remain in high value. and cl and cd oscillate.

giuli@ October 24, 2011 06:03

I would put Pressure Far Field for all the boundaries.
kw-SST usually is the most accurate; but for airfoil you can use Spalart-Allmaras, is computationally cheaper than kw-SST and was developed especially for this application.
Under-relax factors: keep the default; if you have problem with convergence it can help if you lower them. But usually, if it does not converge, there must be a problem either in the formulation of the problem (BC) or in the mesh, or in the geometry..

Hope this help :)

cheers

morteza08 October 31, 2011 13:46

Thank you so much dear Guili

aerospaceman November 23, 2011 05:40

You have to watch out for transition, as none of the RANS models accurately captures it. Therefore your Cd maybe higher than results obtained in the literature. XFOIL should also help.


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