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June 10, 2010, 06:34 |
1.#qnb
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#1 |
New Member
marie
Join Date: May 2010
Posts: 21
Rep Power: 15 |
Hello,
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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August 8, 2010, 19:38 |
Hi
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#2 |
New Member
Ehsan Esmaili
Join Date: Aug 2010
Posts: 2
Rep Power: 0 |
Hey, I am getting the same problem with 1.#qnb. I was wondering how did u replace your real by float?
Thanks |
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July 31, 2012, 18:32 |
i had the same problem
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#3 |
New Member
ARSLAN
Join Date: Nov 2009
Posts: 5
Rep Power: 16 |
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 horizontal...it seems that this boundary must be also a lower boundary...in my simple geometry at least)))) hope that it will be helpful...to someone..))) |
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November 15, 2013, 13:07 |
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#4 |
Senior Member
Join Date: Nov 2013
Posts: 1,965
Rep Power: 26 |
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: 1.#QNANe+00 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 1.#QNBe+00 If you see this, it means that something in the calculation went wrong. It can have many, many different causes. |
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November 16, 2013, 06:52 |
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#5 |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,396
Rep Power: 46 |
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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November 19, 2013, 14:35 |
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#6 |
New Member
Hem
Join Date: Aug 2013
Posts: 6
Rep Power: 12 |
Hello,
In my case, #QNB is coming after around 3500 iterations. So how can I know what is going wrong? |
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