calculate the flow velocity

by supernova1387
Tags: bernoulli, fluid, velocity
supernova1387 is offline
Jul7-13, 09:14 AM
P: 30
This might be simple but I can't remember how to do it.

problem: we have 2 tanks. One filled with atmospheric air at 1 bar and the other is vacuum. The two tanks are connected by a rigid pipe which has a valve. I open the valve and air flows to the vacuum tank. How do I calculate the air velocity?

P.s: I don't think Bernoulli is valid here because the flow isn't steady I guess. Please state your assumptions clearly.

Thanks in advance
Phys.Org News Partner Physics news on
Physicists consider implications of recent revelations about the universe's first light
Vacuum ultraviolet lamp of the future created in Japan
Grasp of SQUIDs dynamics facilitates eavesdropping
Baluncore is offline
Jul7-13, 09:37 AM
P: 1,308
Flow velocity depends on the thickness and length of the pipe, and on the temperature of the air.
SteamKing is online now
Jul7-13, 11:23 PM
HW Helper
P: 5,581
Instead of 'thickness' of the pipe, the term 'internal diameter' would be more apt.

boneh3ad is offline
Jul7-13, 11:51 PM
boneh3ad's Avatar
P: 1,443

calculate the flow velocity

Also pay attention to the pressures. The flow is going to start off choked but will eventually un-choke as the pressures equalize.

Register to reply

Related Discussions
Convert an oscillating flow into a flow of constant velocity Advanced Physics Homework 0
Convert an oscillating flow into a flow of constant velocity Engineering, Comp Sci, & Technology Homework 0
Fluids, flow velocity and flow rate. Introductory Physics Homework 2
How to calculate flow velocity in bypass duct Mechanical Engineering 0
flow rate relation? (velocity distribution in pipe flow) Mechanical Engineering 1