ISO 13550:2002
[Current]
Hydrometric determinations — Flow measurements in open channels using structures — Use of vertical underflow gates
...lar flow and submerged flow
Modular flow turns into submerged flow, or conversely, at the so-called modular limit for which the equation is
related to the contraction coefficient C
C
, H
1
and a, as shown by the equation:
C21
C
116 1 1
2
ChH
aaC
?...
...Taking H
1
= h
1
, values of h
2
/a can be calculated for any C
C
value, provided that two-dimensional flow occurs...
...Figure 6 shows the modular limits for a sharp bottom edge, C
C
= 0,611 and a well-rounded bottom edge,
C
C
= 0,990...