Hi everyone

I am trying to simulate heave motion of a ship using dynamic meshing. I have used a udf to define regid body motion of the ship and I have assigned the fluid zone as deforming.

I am getting follow error ..

WARNING: non-positive volumes exist.

Error: Update-Dynamic-Mesh failed. Negative cell volume detected.

Error Object: ()

I tried smoothing the mesh, which does helps for a while. But the error repeats again and again.

Please help me.

Thanks

Manoj

Run grid => check. It seems you have negative volumes. If grid check failed you have to maintain the grid. Try to locate the negative volumes in gambit and remesh those areas.

[kozalp]

Hi everyone,

I am trying to simulate a piston motion in a lateral cylinder.

I defined a piston profile and profile simply consists of time-location data, such as:

(time
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
)
(x
1.2
1.225
1.25
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
1.275
))

When I give a constant move to the piston, I can solve the case; but when I define a profile like the above one, it gives negative cell volume error. It gives error when I give a periodic piston motion too. With periodicity what I mean is that piston moves-stops and moves again periodically. There is no oscillating motion.

What might be the problem. The case looks simple but I cannot solve it. By the way, my mesh consists of quad meshes and the case is 2D.