I have read that in an artery, the blood pressure is greater in an opene artery than in a blocked/constricted one.
Why is this the case?
Looking at the Bernoulli equation,
Pressure + 1/2*density * velocity^2 + density * gravity * height is constant. In a constriction, area goes down, and as flow-rate = velocity * area = constant, as area decreases, velocity increases. As density and gravity and height are assumed to be constant, Pressure must decrease in this constriction.
However, I can't physically udnerstand why this is the case. If I blocked off a part of a pipe, wouldn't pressure increase at that area, as fluid couldn't pass through as easily and e.g. would be putting a force on the constriction?