Weird Velocity Field for Capillary Flow in a Horizontal Tube
 

Dear All,
I am new to use VOF to simulate Transient capillary flow. I tried to setup a simple 2D case for a water capillary flow in a horizontal tube (no gravity). Here are some setups:
(1) The contact angle is 60 degree, and the surface tension coefficient is 0.04 N/m.
(2) The liquid is set as the second phase and the air is the primary phase. I patched a region near the pressure inlet being filled with liquid.
(3) The time step is 1e-5 sec.

The volume fraction result seems ok. But, there are two problems make me feel that there is something not correct for my case:
(1) The interface seems wavy (please see figure 1). Anybody has the same problem? is this normal? Or this is due to some numerical inaccuracy?
(2) The Y-velocity field is weird for me. It seems that my calculation is wrong based on the Y-velocity contour (please see figure 2). If you know how to correct this, please let me know. Thank you very much in advance!!!

Yu

https://lh4.googleusercontent.com/J7..._TXJ--MXQ=s180

https://lh3.googleusercontent.com/8_...2of56e9sw=s180

I couldn't load the pictures you had attached somehow but based on your statement I seem to have the same problem as you (or maybe not). Had you possibly resolved the issue? If yes I really hope to hear from you.

The picture is as attached.

https://imagizer.imageshack.us/v2/25...540/6T0sig.png

Thanks.