Pressure theory applied to a Venturi tube

extricate

Hi,

I'm a little confused about the pressure in the inlet/outlet and the throat of a Venturi tube.

Why is the pressure in the inlet/outlet greater than in the throat? I thought that because air is needed to flow into a smaller space so the pressure has to be greater?

Pardon me. I've self-learning.

Thanks for your time.

tiny-tim

hi extricate! welcome to pf!

it's conservation of energy (density) …

Bernoulli's equation is simply a conservation of energy (density) equation

(and pressure is energy density: pressure = work done per displaced volume = energy per displaced volume)

where the tube is narrower, the speed is faster, so the kinetic energy density is greater

so the pressure must be less

extricate

Thanks alot for the reply.