I have a venturi tube and downstream of it, there is a small secondary opening at the end of the throat. This is where the local vacuum is created as the velocity increases and the pressure decreases. This difference between this pressure and the atmospheric pressure will induce air into the secondary opening. Does anybody know if I have to use another equation for the rate of air induction versus this differential pressure or will the same Bernoulli's equation for pressure drop through the venturi tube still apply? If there is another equation, do you know what it is? Thanks!