# Homework Help: Pressure drop

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1. Jun 16, 2015

I have a container with one inlet and one outlet. I have the area of the inlet, Ai, velocity vi of the air coming in, and mass flow mi (assume a plane with an air inlet to a bay). I don't know anything about the outlet (just that there is one). What I need to do is calculate the size of an extra hole to be made in the bay so that the pressure in the bay reaches a certain value P2, which is lower than the stagnation pressure of the air coming in the bay.

I approached the problem with the Bernoulli law, as I ignore the incompressibility of the air. So I have Pstag in the bay, which is static pressure + dynamic pressure of the air coming in, and outside the bay I have the ambient pressure. Is the pressure difference between the bay inside and outside Pstaginside-Pamb or does the dynamic pressure of the air outside the pressure play a role?

And after that?

I can explain more if it is not clear enough. Thank you in advance for all the tips.

2. Jun 17, 2015

### ElizabethYup

Can you give the numbers too?

3. Jun 17, 2015