# Fluid dynamic and pipe

1. Mar 6, 2016

### lurifax1

1. The problem statement, all variables and given/known data
http://imgur.com/DSBFIeO
I want to find the flowrate through this pipe based on the pipe's diameter, height of the pipe and the pressure difference. I tried to use Bernoulli, but since the diameter on either end is the same, the terms cancel out. I guess Bernoulli's equation doesnt apply in this example

2. Relevant equations
https://en.wikipedia.org/wiki/Bernoulli's_principle
https://en.wikipedia.org/wiki/Hagen–Poiseuille_equation

3. The attempt at a solution
$P_1 + \rho g h_1 + \dfrac{1}{2}\rho {v_1}^2 = P_2+ \rho g h_2 + \dfrac{1}{2}\rho {v_2}^2 \\ {v_2}^2-{v_1}^2 = \dfrac{|P1-P2|-\rho g h_2}{0.5\rho}\\[2mm]$
I also looked at Poiseuille's equation: $\dfrac{\Delta V}{\Delta t}=\dfrac{\pi r^4 (P_1-P_2)}{8\eta l},\\[2mm]$
but this does not take the height of the pipe into effect.

2. Mar 6, 2016

### vinamas

man the forums are dead now could you please take a look at my homework?