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Calculations  
Palmer Bowlus Flume and H-Flume  
ABSOLUTE 
If the flow calculation is to be absolute P702 = 1 the flow will be calculated 
using the formula: q = f(h)
 
Where:  q   = flowrate         
 f   = is an 8
th
 degree polynomial solution for h (head)  
RATIOMETRIC 
If the flow calculation is to be ratiometric P702 = 2 the flow will be 
calculated using the formula: q= q
cal 
f(h)/f(h
cal
) 
 Where:  q         = flowrate      
q 
cal      
= flowrate at maximum head P705    
f(h)     = a polynomial solution for h (head)     
f(h
cal
)  = a polynomial solution for h
cal 
(maximum head) 
V-Notch Angle Weir (Non BS 3680) 
ABSOLUTE 
If the flow calculation is to be absolute P702 = 1 the flow will be calculated 
using the formula: q = C
e 
8/15 tan (theta/2)(2gn)
0.5
(h = kh)
2.5 
Where:  q       = flowrate            
 C
e
 = discharge coefficient calculated by Ultra Twin P723                      
theta  = V-notch angle     
gn      = gravitational acceleration         
h        = head    
kh      = compensated head 
RATIOMETRIC 
If the flow calculation is to be ratiometric P702 = 2 the flow will be 
calculated using the formula: q= q
cal  
(h+kh/h
cal
+kh)
2.5
 
Where:  q     = flowrate   
q 
cal  
= flowrate at maximum head P705    
h     = head      
kh   = compensated head