I was recently looking at some closing characteristics of valves (the relationship between the opening area of a valve and its stroke) and couldn't wrap my head around something.
Why exactly the flow rate of an incompressible fluid decreases as you decrease the valve opening? What is the physics behind it?
If the fact that the fluid flowing is incompressible implies that different cross-sections of a tube have the same flow rate, what am I missing here?
I appreciate any insights, thanks in advance.