Which of the following is /are correct?
If the sewer is flowing partially full as shown.
Where
p = Wetted perimeter.
P = Full perimeter of the sewer.
a = Wetted area.
A = Full area of the sewer.
r = Actual hydraulic radius.
R = Full flow hydraulic radius.
1
\({d\over D}={{1\over2}(1-cos{\alpha\over2})}\)
2
\({p\over P}={\alpha\over180}\)
3
\({a\over A}=({\alpha\over360}-{sin2\alpha\over8\pi})\)
4
\({r\over R}={({\alpha\over360}-{sin\alpha\over2\pi})\over{\alpha\over360}}\)