$12\mathrm{.}4$ Approach to Steady Flow

$557$

$($b$)$ For the other two lengths the minor losses are insignificant $($Sec$.8\mathrm{.}27),$ and the results are as follows:

Exercises

$12\mathrm{.}4\mathrm{.}1$ A $4-$in$-$diameter drain pipe $($flush entrance, $\backslash ($ f$=0\mathrm{.}020\backslash ))3000$ ft long will freely discharge reservoir water at an elevation $100$ ft below the reservoir water surface. Initially there is no flow, since there is a plug in the pipe outlet. What will be the steady flow velocity in this pipe, and how long after the plug is removed will the flow velocity be half the steady velocity? See Sec. $8\mathrm{.}27$ regarding the neglect of minor losses.