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-   -   axisymetric-WARNING:non-positive face area exist (http://www.cfd-online.com/Forums/fluent/38547-axisymetric-warning-non-positive-face-area-exist.html)

JORDI November 9, 2005 14:36

axisymetric-WARNING:non-positive face area exist
 
i've got an error checking the grid in an axysymetric problem in 2d. the x axis is my revolution axis and i don't understand why i have a zero face area.(using fluent 6.2.16 )

can anybody help me--thanx a lot in advance.JORDI ARMENGOL

Grid Check

Domain Extents:

x-coordinate: min (m) = 0.000000e+000, max (m) = 5.000000e+001

y-coordinate: min (m) = 0.000000e+000, max (m) = 2.000000e+002 ...

WARNING: non-positive face area exist.

minimum face area (m2): 0.000000e+000

maximum face area (m2): 7.691770e+002

JORDI November 9, 2005 14:50

i foget
 
that if i check the grid with 2d solver (not axisymetric) i won't give the error -- the grid check is ok

sorry

KP November 9, 2005 15:24

Re: i foget
 
check BC, skeweness, and also check the box Import 2d mesh while exporting it from Gambit. KP


JORDI November 9, 2005 17:39

Re: i foget
 
it's a very simple problem with only two bc. and i have done similar models and i think it is not the problem. i always have the box "import 2d mesh" but i dont know how to check the skewness (i don't know whats skewness) can you give me some notes thanx. JORDI

KP November 10, 2005 07:52

Re: i foget
 
length to breadth ratio of a single cell should be less than 5:1. This is mantained in order to avoid numerical diffusion. Higher order numerical schemes can also be tried but defaults are best suited for most of the cases.

Check your case. I presume something wrong with BC ... KP

JORDI November 10, 2005 09:19

Re: i foget
 
i don't know what to do with BC. i have checked the mesh without the axysymetric solver (with 2d) and the result is ok? what can happenb to my model? thanx again.

Alec Eiffel November 10, 2005 10:24

Re: i foget
 
axi symmetric models must have the axis of rotation on the cartesian x-axis. I think this may be the problem. hope this helps

hongfw November 10, 2005 10:45

Re: axisymetric-WARNING:non-positive face area exi
 
Open the Grid/Translate, check if the the Ymin is less than zero. If it is, translte the grid making the Ymin equal to zero.

JORDI November 10, 2005 13:41

x axis of rotation
 
thanks but the x axis is my rotation axis indeed. i don't know... thanx again

mohsen zendehbad March 9, 2011 06:15

Dear friend, were you finally able to solve this problem? we're facing the same problem now!


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