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CL is so high

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Old   February 16, 2023, 15:00
Question CL is so high
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Eduardo Ireta
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Hi, i new in OpenFoam, I try to make a simulation to get the cl of a plane but i have 3 problems:

1.-The principal problem is for the cl is so high, I'm trying to make a comparison with several CFD programs (fluent, xflr5, OpenFoam) and the cl is like to 0.28, but in OpenFoam i got 3.3. I donīt know what is the problem, i change several values like Aref, Umag, etc..

2.-The simulation never converges, I end up truncating the simulation at time 500 or 1000 for get the values.

3.-When I visualize the results in openfoam and the end of the control volume the speed rises very quickly until it reaches 30 m/s. If I increase the size of the control volume in that direction, the speed continues to increase.

I would like to know what my faults are so I can learn more about openfoam.

This is the directory link
https://drive.google.com/drive/folde...jj?usp=sharing
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Old   February 17, 2023, 13:42
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Tobermory will become famous soon enough
Point 1 (bad CL prediction) is probably lined to / the result of point 2 (poor convergence), as is 3 (unphysicak results).

Taking a brief look at your model - forgive me for saying, but your mesh is awful. Your mesh refinement zone seems to have missed your geometry, and the resolution at the outlet is probably too coarse - see the attached. My advice is to start by getting a better mesh.

If the case still falls then we'll need to look at the BC's ... I didn't open them. But start with the mesh. Good luck!
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aerodynamic, cfd, coefficient of lift, converge cfd, openfoam

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