Okay, I am following your recommendation for first cell height. From the contour graph, I see that there is no film just after the inlet section. This might be the reason for abnormal/negative velocity just after the inlet. But one thing I notice is that film thickness and film velocity at the bottom and up of the pipe are different. As I am injecting liquid mass flux around the circumference uniformly using the EWF model, film thickness and velocity should be the same around the pipe. Is there any specific reason for happening these?
As the film thickness is disappearing at the inlet, should I simulate for a longer period? From the experimental result, I only know the liquid mass flow rate at the inlet.
Flim thickness contour-
Film Velocity:
Regards Anadi