remeshing problem
 

I'm trying to simulate piston oscillating in in cylinder(a compressor). I've met with some problems which i hope someone can help... my problem 2d axisymetric dynamic one.

Choose the remeshing and smoothing option I've selected piston with rigid body motion with the udf profile just compiled.

Cylinder and axis as deforming one. Setted the value as in poppet valve example in BC condition where to set the velocity of wall (a udf function). ?????? Is it require. ? i am getting negative volume problem. how to solve ? from mesh motion review i got it is not remeshing plz reply ammi