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SimpleFoam: Weird low velocity region/bar at leading edg |
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#1 |
New Member
Kyfrankie
Join Date: Oct 2020
Posts: 5
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The case is ran with SimpleFOAM using kOmegaSST turbulence model at RE=50000, free stream velocity of 4.8m/s. The solution reached a steady "converged" stage but the residual of p fail to drops below 1e-3, others residuals are okay though. However, when viewing the U in paraView, there's two weird low velocity region at the leading edge. I am puzzled about what is going on
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#2 |
Senior Member
Troy Snyder
Join Date: Jul 2009
Location: Akron, OH
Posts: 219
Rep Power: 19 ![]() |
The "lines" appear to coincide to the transitions in surface mesh density. I suspect the low velocities are of numerical origin.
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#3 |
New Member
Kyfrankie
Join Date: Oct 2020
Posts: 5
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Thanks a lot for your reply. I have made the refinement level to the same (6,6) and the "line" seems to be less aggressive but still appear. In addition, if the force coefficient converged to a stable value but the residuals fail to drop below 1e-4. Is it still considered converged? Any advice to improve convergence? Thanks in advance!
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#4 | |
Senior Member
Troy Snyder
Join Date: Jul 2009
Location: Akron, OH
Posts: 219
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Quote:
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#5 |
Senior Member
Michael Alletto
Join Date: Jun 2018
Location: Bremen
Posts: 616
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There may be some reciculation regions on the right edge of the airfoil which explains the high pressure residuals.
Regarding the low velocity close to the leading edge did you check if you can expect a laminar recirculation bubble. Michael |
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#6 |
New Member
Kyfrankie
Join Date: Oct 2020
Posts: 5
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I believe the "line" may be caused by an issue in the STL file. Also, I found that by setting the refinement of the Wing to be uniform (6 6) instead of (6 7) helps the convergence after adding a absolute layer near the wing wall.
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#7 |
Senior Member
Michael Alletto
Join Date: Jun 2018
Location: Bremen
Posts: 616
Rep Power: 16 ![]() |
The stl seams to be not smooth. So probably you have to fix this first. Do you have wall layers? What kind of boundary conditions are you using
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