# Mesh is doing some problem

 Register Blogs Members List Search Today's Posts Mark Forums Read

May 21, 2015, 09:01
Mesh is doing some problem
#1
New Member

Shailesh
Join Date: Mar 2015
Posts: 16
Rep Power: 10
hey guys

i made a 2d mesh in design modular then make a normal tetragonal mesh. But as i call it to fluent and check the mesh in 2D Space-Planer its says mesh is ok. But on the other hand as i click 2D Space-Axis symmetric it is giving me negative volume. please help.

2D Spacer - Planer :

Domain Extents:
x-coordinate: min (m) = -8.996571e-03, max (m) = 0.000000e+00
y-coordinate: min (m) = -2.000000e-03, max (m) = 5.982000e-03
Volume statistics:
minimum volume (m3): 1.243186e-10
maximum volume (m3): 1.291856e-09
total volume (m3): 3.774166e-05
Face area statistics:
minimum face area (m2): 1.365747e-05
maximum face area (m2): 4.111103e-05
Checking mesh.........................
Done.

2D Spacer - Axis symmetric :

Domain Extents:
x-coordinate: min (m) = -8.996571e-03, max (m) = 0.000000e+00
y-coordinate: min (m) = -2.000000e-03, max (m) = 5.982000e-03
Volume statistics:
Warning: non-positive volumes exist.

minimum volume (m3): -1.122491e-11
maximum volume (m3): 4.001538e-11
total volume (m3): 4.688673e-07
minimum 2d volume (m3): 1.243186e-10
maximum 2d volume (m3): 1.291856e-09
Face area statistics:
minimum face area (m2): 1.365747e-05
maximum face area (m2): 4.111103e-05
Checking mesh..........
WARNING: left-handed faces detected on zone 1: 65937 right-handed, 17976 left-handed.
WARNING: left-handed faces detected on zone 5: 0 right-handed, 10 left-handed.
WARNING: left-handed faces detected on zone 9: 183 right-handed, 67 left-handed.
WARNING: left-handed faces detected on zone 10: 1260 right-handed, 344 left-handed.
Info: Used modified centroid in 33 cell(s) to prevent left-handed faces.
It is recommended that you try to fix the left-handed faces
via the TUI command
/mesh/repair-improve/repair.
....
WARNING: Invalid axisymmetric mesh with nodes lying below the x-axis.....
WARNING: The mesh contains high aspect ratio quadrilateral,
hexahedral, or polyhedral cells.
The default algorithm used to compute the wall
distance required by the turbulence models might
produce wrong results in these cells.
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.
using the text user interface to switch to the
alternative algorithm.
........
Done.

WARNING: Mesh check failed.

To get more detailed information about the mesh check failure
increase the mesh check verbosity via the TUI command
/mesh/check-verbosity.
Fluent can also try to fix the mesh check problems via the TUI command
/mesh/repair-improve/repair.

Any possible Suggestion will be appreciated.
Attached Images
 asd.jpg (44.3 KB, 51 views)

 May 21, 2015, 10:53 #2 Senior Member   Join Date: Nov 2013 Posts: 1,965 Rep Power: 26 Axi-symmetry means that you can rotate your model around an axis. What would the axis in your case be? (Your geometry has negative x and positive x, and negative y and positive y. So should can not be around x=0, and also not around y=0.)

 May 21, 2015, 15:05 #3 New Member   Shailesh Join Date: Mar 2015 Posts: 16 Rep Power: 10 First of all, my geometry didn't have +ve x . And its axis is X = 0;. Please Help Last edited by prwl120; May 22, 2015 at 03:19.

 Tags ansys 14, fluent 14, need help, negative cell volume