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Problem simulating transient flow for iced conductor

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Old   February 23, 2018, 10:04
Default Problem simulating transient flow for iced conductor
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Alvise
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Dear all,

I am trying to evaluate drag an lift forces of an iced conductor profile for different angles of attacks. I am using a paper which dealt with this type of problem and I am tying to reproduce the same configuration and to find the same results.
The geometry is fixed, while velocity components (and thus drag and lift) change accordingly to the AoA.
I am working with a 2D simulation, unstructured triangular mesh for the whole domain and structured mesh in the surrounding of the body, achieving a y+ approximately equal to 1. It is a transient pressure-based simulation, the model is k-omega SST (v_inlet =10 m/s) with Low-Re correction. I am using SIMPLE as solution method and second order discretization. I am monitoring drag and lift forces, instead of coefficients so that to separately deal with the reference values in the data processing. As time step I am using 0.0007 s, obtained by assuming a Strouhal number equal to St=0.2. Maximum iterations per time step are 30. I leave the simulation running for at least 30000 iterations.

The problem is basically that for high angles of attack solutions are not anymore comparable with the results found in the paper which I am trying to validate. Both lift and drag fluctuate on values significantly higher. In contrast with this, for small AoA results are very close.

I would like to ask you if you have any suggestion on what could be the problem. I have already tryed different types of meshes and settings but the problem seems the same.

Please find attached the link of the validation paper (I am basically using the same setup), and mesh and results pictures.

Please let me know if you need further information.

I really hope you can help me out. Thank you.

Alvise


Link for validation paper:

file:///C:/Users/alvis/Desktop/Validation%20paper.pdf
Attached Images
File Type: png Mesh.png (63.0 KB, 3 views)
File Type: png AoA30.png (110.1 KB, 2 views)
File Type: png AoA70.png (125.2 KB, 1 views)
File Type: png TypicalResiduals.PNG (34.1 KB, 2 views)
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Old   March 1, 2018, 09:39
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Old   March 16, 2018, 09:48
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Still not able to find the problem...
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angle of attack, divergence, lift and drag, validation

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