[Morelz]

Hi,

my case in simple but i cannot send pictures of it, so i have to describe what i'm working on;

I´m working on a 3D moving furnace grate to burn biomass.
I have only one step of that grate, translating discontinuously forward and backward only X axis, that compresses the mesh in front of it while enlarging the one behind. so it´s something similar to the piston of a 2 stroke engine (but the face is squared and not cylindrical)

I´m working with FLUENT 15 on a DYNAMIC MESH moved by a UDF (DEF_CG_MOTION) with LAYERING feature (ratio based 0.4 / 0.4), since the cells are hexaedral.

The quality of the mesh is good, despite few cells (> 0.01 %) with high skewness or low quality ratio.

THE PROBLEM IS: during the PREVIEW of the mesh movement, after 2 movement of the step (30sec), appears the warning "left-handed faces detected". If i ignore it the simulation runs until 98 sec, then NEGATIVE VOLUME error appears and blocks everything.

I tried with a lot of different brief timesteps but there isn´t influence, since the speed is very low and cells are quite big (1cm)

I tried whit the "mesh repairing tools" but, despite sometime it works (and i´m also able to check the mesh) the negative volume is detected as well at 98sec.

I DON`T have any problem in using the "DISPLAY MESH MOVEMENT"

Someone has encountered a similar problem or can advice me on how proceed to discover new info about this error?

I thank you all!

[ndabir]

I have the same problem exactly! Have you solved it?