While there are a lot of researches on dynamics of wetting and dynamics contact angle, it seems, Ansys fluent update contact angle during simulation. For example if you set static contact angle for a liquid slug in a capillary tube, and then force the slug to move, the contact angle changes.

In this regard, I saw a lot of discussion on how to write a udf to apply dynamic contact angle, when the "wall adhesion" option is activated while I think fluent solver updates the contact angle during simulation and there is no need to do so by a udf.  

Actually I'm a kind of confused on this issue and wonder if  you can help me?!