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lift & drag coefficient on 2d airfoil

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Old   March 31, 2015, 13:53
Default lift & drag coefficient on 2d airfoil
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Ronald Thompson
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Hi,
im trying to determine lift and drag coefficients from my fluent model and validate them against publications, at the moment I can't get my Cl and Cd to match with the published material, Im using a NACA0018 airfoil and at the moment i'm only dealing with small AOA <10 degrees, I'm using an Inviscid model in fluent, with a C mesh for my fluid domain, (see mesh attached) Ive used an automatic triangles method in general and then applied sizing around the foil with inflation in this area also.

Ive carried out a mesh convergence test and i do get my results to converge but not to the correct answer, i seem to be an order of magnitude out in most cases. my boundary conditions seem to be correct,

I dont know where exactly the issue is, any help would be appreciated.
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Old   March 31, 2015, 15:38
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What is your reason for using Inviscid flow? Are you comparing your results to other CFD calculations or real world results? You should consider your Reynolds number too. Check your reference values to make sure they are correct for calculating the CL and CD.
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Old   March 31, 2015, 18:54
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Ronald Thompson
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hi, the results i am using for comparison are based off published experimental results. I have considered the Reynolds number I used it to ensure i was making the correct comparisons, the reference values also seem to be correct. the reason I chose an Inviscid model was because I seen it in a tutorial previously and i was only using it on small angle of attacks, as I was presuming a turbulence model wasn't necessary with a Reynolds number based off 160k, I also had ran a version using a Laminar flow model but still could not get any closer to the required results.
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airfoil 2d, coefficient drag., coefficient of lift, fluent 14.5

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