dynamic mesh DEFINE_GRID_MOTION
 

Hello,

I am currently trying to write a code for a FLUENT UDF file. My model is a 3-d tube with 9.5mm radius and 20mm length with tube protruding in y direction with y axis going through center, x and z are in the radial direction (x up and z comming out). The origin of the axis is at the left end of tube at center of tube. I have two steps I would like to complete:
1. To have motion in the radial direction so the tube expands and contracts over a certain time period (lets say 10s).
2. To have radial motion at a certain point that starts at y=0 and ends at y=20 over a time period. Basically so there is a wave propagation in the axial direction down the tube.
This is to model a pulsating water flow through an elastic rubber hose. As of now I am not concerned with accurate radial deflection values or any values for that matter. I would just like to have the general motion for each case. As of now I am just trying different codes and checking the mesh motion under display-->zone motion and solve-->mesh motion, but am not getting even close to desired results. From what I have read so far I believe the DEFINE_GRID_MOTION MACRO is the MACRO I am wanting to use, but maybe DEFINE_GEOM would be better, I am not sure. I have read through the Fluent UDF manual, other examples, and have exhausted my google search efforts; however I am still at a loss for how to write a code that would work for my case. If anyone has any suggestions that would help me with this problem it would be very appreciated. Thanks.