1.#qnb

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 June 10, 2010, 05:34 1.#qnb #1 New Member   marie Join Date: May 2010 Posts: 21 Rep Power: 9 Sponsored Links 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.

 August 8, 2010, 18:38 Hi #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

 July 31, 2012, 17:32 i had the same problem #3 New Member   ARSLAN Join Date: Nov 2009 Posts: 5 Rep Power: 9 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..)))

 November 15, 2013, 13:07 #4 Senior Member   Join Date: Nov 2013 Posts: 1,074 Rep Power: 14 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.

 November 16, 2013, 06:52 #5 Senior Member     Alex Join Date: Jun 2012 Location: Germany Posts: 1,506 Rep Power: 25 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.

 November 19, 2013, 14:35 #6 New Member   Hem Join Date: Aug 2013 Posts: 6 Rep Power: 5 Hello, In my case, #QNB is coming after around 3500 iterations. So how can I know what is going wrong?

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