If going to a smaller tube causes a PSI increase in the small tube, the following would be true:
1) You breath air at atmospheric pressure, but in the alveoli in your lungs experience thousands of PSI of pressure
2) when you pump your car tire to 30PSI, the thin tube on the pump is experiencing thousands of PSI
3) the pressure inside the round part of a balloon is lower than where you tie the knot
the psi to velocity thing. (ignore conductance)
when you cut the area in 1/2, you get 2x the velocity, but you only require 1/2 the force to push it. Since the force and area are cut in 1/2, PSI remains the same since PSI is force/area (0.5force/0.5area) = (1force/1area)
1) You breath air at atmospheric pressure, but in the alveoli in your lungs experience thousands of PSI of pressure
2) when you pump your car tire to 30PSI, the thin tube on the pump is experiencing thousands of PSI
3) the pressure inside the round part of a balloon is lower than where you tie the knot
the psi to velocity thing. (ignore conductance)
when you cut the area in 1/2, you get 2x the velocity, but you only require 1/2 the force to push it. Since the force and area are cut in 1/2, PSI remains the same since PSI is force/area (0.5force/0.5area) = (1force/1area)