Generate a perturbation
 

Hello Friends,

I want to model a wave propagating in a pipe with two fluids (air and water) flowing. I was able to simulate stratified flow using VOF. My aim is to generate a perturbation at the inlet (velocity inlet BC) and observe its propagation on the free surface with variation in velocities of air and water. I read the "wave generation in a tank" tutorial but it has a moving boundary which I do not want. (Here is the link: http://www.fluent.com/software/sf_me...orial_wave.htm)

How can I achieve my aim without a moving boundary. Should I use a UDF? If yes, can anyone help me write a simple UDF for a small perturbation at the inlet at time t=0, as I have had no prior experience with it. Also, please let me know if I can use the UDF that comes along with the wave-tutorial package by editing it?

Thanks,
Pranab