254 Molesworth’s pocket-book
Flow of Water in Pipes.
COMFABISON OF FORMULÆ.
R = Mean hydraulic depth in feet = Area 4. wet peri-
meter = - fori circular section of pipe.
S = Sine of slope = 5 •
L
v = Velocity in feet per second.
d = Diameter of pipe in feet.
L = Length of pipe in feet.
H = Head of water in feet.
Prony d = 97-05 ^RS - 0-08 ;
or v = 99-88 v'R S — -154.
Eytelwein v = 50 a/ H .
v L + 50 d '
„ v = 108 Vk S - 0-13.
Hawkaley - = 48 \/____.
L + 54 ci
Neville v = 140 ^RS- 11 5/kS?
Darcy i> — C VR S; for value of C, see table.
Diam, of pipe, ins J } Value of C.. .. | 65 1 2 3 4 I 5 I 6 7 8
80 ' 93 99 102 [ 103 |105 106 10T
Diam of pipe I 9 Value of C.. .. ‘108 10 I 12 I 14 1 16 118 1 20 109 109-5[110|110-5|110-7 111 22 111-5 24 111-5
Maximum value of C for very large pipes, 113-3,
Kutter v — C \Ar S; where
C =---------------------------.
1 + -02é ^41’6 +
Weisbach h — — (-0036 + ~-
where h = head necessary to overcome the friction in a pipe,
and r — the mean radius of the pipe in feet; g — gravity —
Parcy h
A) 21.
d \ 12 d> 29