Civil Engineering Reference
In-Depth Information
L
a
L
b
H
b
H
a
B
B
W
Flow
1
1
3
6
L
1
L
2
L
Plan View
Fig. 26-41.
Dimensional configuration of rectangular cutthroat flume (
Source:
Reference 25;
illustration courtesy of Isco, Inc.)
Q
KW
H
(26-42)
1.025
n
CH
n
(26-43)
where:
Q
flow rate, mgd
k
free-flow coefficient
C
free-flow coefficient
W
throat width, W
H
water depth, ft
n
free-flow exponent
The coefficients are shown in Table 26-10.
FLOW MEASUREMENT—CLOSED CONDUITS
Conduit Flow Elements
There are several types of devices used to measure flow in pipes. These include dif-
ferential pressure units, positive volume displacement units, direct discharge measure-
ment units, and velocity-area measurement units. There are several items to consider
before selecting the device to use, as follows:
