CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   FLUENT (https://www.cfd-online.com/Forums/fluent/)
-   -   problem (https://www.cfd-online.com/Forums/fluent/150903-problem.html)

Radwanma March 31, 2015 17:35

problem
 
Hi all,

I have this problem when I have done solution in Fluent but I can not solve it

" WARNING: Limited wall distance for 28 cells to 1.000000e-12.
Please inspect the wall distance by displaying the
contours of the 'Cell Wall Distance' at the
boundaries. If you observe any irregularities we
recommend the use of an alternative algorithm to
correct the wall distance.
Please select /solve/initialize/repair-wall-distance
using the text user interface to switch to the
alternative algorithm.

iter continuity x-velocity y-velocity z-velocity k omega Cl-aerofoil Cd-aerofoil time/iter
# Divergence detected in AMG solver: x-momentum -> Increasing relaxation sweeps!

TobM April 1, 2015 08:40

I had this kind of warning a while ago when simulating nozzle flow with an y+ < 1 mesh. In my case the cell wall distance in the first cell layer near the wall was not correct, it got bigger, than smaller than bigger and so on, when it only should get smaller.
In my case I meshed the region with a different method with the ANSYS mesher and the problem was solved. I suspect this happens, when the mesh accuracy has to be very high.
You can visualize the cell wall distance as stated in the warning message to see if it is the same problem in your case.

haitham osman March 31, 2016 16:50

using TUI
 
--write in command screen--
solve (press enter)
initialize (press enter)
repair

LuckyTran April 1, 2016 13:06

It's likely a meshing problem. You have cells that are much smaller than the minimum threshold for the distance to the nearest wall. This can be caused by skewed cells or you have very very very small cells next to walls in your mesh.

Note that 1e-12 m is 1 pm, which is a sub-atomic length scale and there is no reason to be doing CFD (fluids) at that length scale.


All times are GMT -4. The time now is 22:47.