Hi i am modeling reciprocating compressor by dynamic meshing (cylinder piston arrangement).

lenght of compressor is=0.0075m radius=r=0.00954m

my udf function for piston is

frequency = f=34hz w=2*Pi*f=213.62rad/s displacement of piston is X= 4.511e-3m piston head velocity =V= 0.9631Cos(w t) i am taking time step=dt= 7.3529e-4s no of time steps = 40 I am getting negative volume problem as follow

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

How to solve this problem.Waiting for your kind suggestions? ammi reddy

Hi Ammi, check your cell sizes in respect to the moving wall velocity. usually you get the statement as soon as the moving cellwall and the stationary wall overlap. kais