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Very strange/incorrect flow solution all of a sudden.

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Old   March 21, 2017, 15:44
Default Very strange/incorrect flow solution all of a sudden.
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I'm trying to simulate airflow around an aircraft. The settings and BCs are as follows:

-Transient flow
-35 m/s in the negative Z direction, normal to the inlet face
-Outflow on outlet face
-Turbulent kinetic energy 4.59375m2/s2
-Turbulent dissipation rate 13001.87m2/s3

I was able to successfully calculate a solution at AoAs of 0 and 5 degrees, but then I tried 10 degrees, changing nothing, and the result was an absolute turbulent mess with large vortices and circulation everywhere. The image below shows the 10 degree result:

(The screenshot is very large so I put it on Imgur:

You can hilariously barely see the plane. It really doesn't look like Fluent is solving the flow from the inlet to me. The solution is just too dead wrong.

So, I tried starting a completely new project and reattempting, to no avail. I went back and tried 5 degrees again, which had worked the first time, and got the same flow mess as the 10 degree solution. I have no idea what changed between that first 5 degree simulation and the first 10 degree sim, but now no solution is accurate.

To me, it doesn't even look like it's solving the flow from the inlet face, even though I've relentlessly gone back time and time again ensuring the inlet face is set properly and the mesh is fine and everything.

I have tried expanding the enclosure and moving the outflow face much farther back, and I get a more streamlined/'more closely converged' vortex around the plane, but it's just as messed up a solution.

Thank you, any help is greatly appreciated.

Last edited by bndrylyr; March 22, 2017 at 18:10. Reason: Image was way too big.
bndrylyr is offline   Reply With Quote


circulation, fluent, vortex, wrong solution

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