Example$-2$

Water is to be moved from a large, closed tank in which the air pressure is $20$ psi into a large, open tank through $2000$ ft of smooth pipe at the rate of $3\frac{f{t}^3}{(s)}.$ The fluid level in the open tank is $150$ ft below that in the closed tank. Determine the required diameter of the pipe. Neglect minor losses.

$\frac{p_1}{}+z_1+\frac{V_1^2}{2g}=\frac{p_2}{}+z_2+\frac{V_2^2}{2g}+f(\frac{l}{D})\frac{V^2}{2g}$

where $V_1=V_2=0,$:$z_2-z_1=150ft,$ and $p_1=20,p_2{?}_{2}0$

Also,