1.#qnb
 

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.

Hi
 

Hey, I am getting the same problem with 1.#qnb. I was wondering how did u replace your real by float?

Thanks

i had the same problem
 

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..)))

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.

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.

Hello,

In my case, #QNB is coming after around 3500 iterations. So how can I know what is going wrong?