help with modeling stratified flow in Fluent

Baker

I am trying to simulate stratified two phase (air-water) flow within a pipe using the VOF model in Fluent. The air velocity is 7.39 m/sec & water velocity is 0.039 m/sec I divided the inlet into two parts one for air & the other for water , the results being good for predicting the velocity profile but the problem I cannot see a clear interface between the phases and when I view the contours of volume fraction the pipe appeared filled with air only knowing that I use unsteady solver with implicit scheme for VOF so who can assist me with this request.

BAKER