Page 116 
U-Throated Flume 
ABSOLUTE 
If the flow calculation is to be absolute P702 = 1 the flow will be calculated 
using the formula:  q = (2/3)
1.5
g
n
0.5
C
u
C
v
C
d
bh
1.5 
Where:  q   = flowrate                            
g
n
 = gravitational acceleration  (nominal value = 980.66 cm/s
2
)  
h   = head       
C
u
= shape coefficient calculated by the Flow 5 P724                                                 
C
v
 = velocity coefficient calculated by the Flow 5 P721        
  C
d 
= discharge coefficient calculated by the Flow 5 P722 
   b   = throat width P711  
 
RATIOMETRIC 
U-Throated Flume 
If the flow calculation is to be ratiometric P702 = 2 the flow will be 
calculated using the formula:   
q= q
cal
(C
v
/C
vcal
)(C
d
/C
dcal
)(C
u
/C
ucal
)(h/h
cal
)
1.5
 
Where:  q        =   flowrate              
q 
cal
 
= flowrate at maximum head P705  
Cv   = velocity coefficient calculated by the Flow 5 P721 
Cv
cal 
= velocity coefficient at maximum head     
Cd      = discharge coefficient calculated by the Flow 5 P722 
Cd
cal 
= discharge coefficient at maximum head  
Cu      = shape coefficient  P724                                              
Cu
cal
  = shape coefficient at maximum head      
h         = head h
cal 
  = maximum head P704