[Josyula]

Hi,
I want to specify advancing and receding contact angle for my problem. The image attached shows a gas bubble (in red).
The front edge of the bubble is receding contact angle (RCA) and the back edge of the bubble is advancing contact angle (ACA). There are models available to specify the DCA models. But, there is an idea which I am playing on.
The idea is this:-
The front edge of the bubble is in the +x direction and the back edge of the bubble is in the -x direction. When it is in the +x direction, I want to specify RCA and when it is in the -x direction, I want to specify ACA.
But FLUENT recognizes the interfaces as 0.5 at both the front and back edges.
So, I was wondering what sort of condition I should specify for this?
Any suggestions?