[avd28]

Hi all,

I'm trying to simulate a biological fluid flow which requires the use of pulsatile sinusoidal wall motion of the mesh. I have the UDF compiled and running. However there is a problem.

Each node is supposed to deform with the equation of the form Asin(wt) where t is the current time.

However, when the time step size is decreased from say 0.1 secs to 0.01 secs, the mesh amplitude unaccountably increases, for the same number of iterations. This of course results in formation of negative volumes in the mesh and the simulation crashes.

I have attached the udf file and will provide a dropbox link to the case file. In order to view the problem, simply simulate with a time step size of 0.01 as compared to 0.1 secs.

https://www.dropbox.com/s/pjdkjink6t...test1.cas?dl=0