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Old   June 10, 2010, 05:34
Default 1.#qnb
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when I run my program, it stops at 3 iterations and on Fluent I can read "solution is converged"
and I have 1.#QNBe+00 that appears...

Does anyone know why?

I replace my real by float but it doesn't change the result.
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Old   August 8, 2010, 18:38
Default Hi
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Hey, I am getting the same problem with 1.#qnb. I was wondering how did u replace your real by float?

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Old   July 31, 2012, 17:32
Default i had the same problem
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the problem i solved was a very simple: axissymmetric (horizontal) channel. I set up a axis BC at the upper boundary of my channel and get this error:

iter continuity x-velocity y-velocity time/iter
! 1 solution is converged
1 1.#QNBe+00 1.#QNBe+00 1.#QNBe+00 0:00:12 999

when i change: the upper boundary set a Wall BC, and the bottom set the Axis BC all fixed and a solution was gone..
I've heard before that Axis BC must be only seems that this boundary must be also a lower my simple geometry at least))))

hope that it will be someone..)))
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Old   November 15, 2013, 13:07
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For those who were directed to this forum by google searching for "QNBe":

1.#QNBe+00 is what Fluent shows when it really does not know what to do, for example when somewhere in the calculation there was a 0/0.

In floating point operations, 0/0 results in NAN (Not Any Number). In Fluent, this is #QNAN. Fluent wants to represent this in exponential notation:
The next thing that happens is that Fluent wants to represent is with 4 digits. N is bigger than 5, so the A is rounded up to B, and it becomes

If you see this, it means that something in the calculation went wrong. It can have many, many different causes.
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Old   November 16, 2013, 06:52
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In this specific case, people really should have read the manual.
It clearly states that the axis of symmetry in an axisymmetric simulation has to coincide with the x-axis.
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Old   November 19, 2013, 14:35
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In my case, #QNB is coming after around 3500 iterations. So how can I know what is going wrong?
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