Can I use UDF function to solve this problem?
 

I want to simulate the process of the methane flow into a dynamic mesh. I hope the methane flows into the cylinder of dynamic mesh when the mesh has moved for a few seconds(the deformation of cylinder can form turbulence), that means I have to control the timing and duration of methane flow. Can I use UDF to define a inlet boundry to do this thing?
Thank you in advance

Yes, I suppose a DEFINE_PROFILE will do.

You means I have to define a periodic pressure profile in udf?

I don't know your precise set-up (concentration, two-fluid or?), but in general you can control your boundary condition in time and space using a DEFINE_PROFILE UDF. You can check the UDF Manual for some examples.