V-notch angle weirs, the head is measured upstream of the weir plate at a
minimum distance of 3 times maximum head to ensure the surface of the
liquid is not affected by turbulence or drawdown. See Exponential devices,
above, for further details.
Palmer Bowlus and H-Flume Calculations
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)