Is this statement correct? In a flow simulation, the resulting velocity and pressure profile within an arbitrary pipe should be VERY similar between using pressure inlet / pressure outlet BC's vs flow rate inlet / pressure outlet BCs?
In other words... If I ran a flow simulation using 1 GPM inlet flow rate and environmental pressure (atm) outlet and my surface goal was pressure drop between the inlet and outlet and this yielded a 2 psi pressure drop.
Now if I set up the same flow simulation with (exact same geometry and mesh) with a inlet pressure of 2 psi higher than the environmental pressure outlet with a surface goal of max volumetric flow rate at the inlet... I should yield 1 GPM inlet flow rate correct? And these two simulations should yield very similar if not exact velocity/pressure profiles correct?
I find running these two simulations (using the result of one sim as a boundary condition of the other) a good way to verify the simulation results.
However, I don't seem to be getting similar results and the velocity and pressure profiles are different.