pipe flow
 

Dear experts:

I want to simule pipe flow. Did I haave to open no sharp interface?
Then, my boundary condition was specific velocity(inlet) and specific pressure for stasic pressure(outlet). Coluld I set up that boundary condition?

If it is the flow of a single fluid without free surface, then, yes, select the no sharp interface option. I think you are right with the mesh BC. You will have to let the velocity profile develop since at the inlet velocity is uniform.