Derivation for Venturi Meter:
If V be the volume of the liquid flowing through a given section in one second, we could write:
or, V = k √h.
where, k ( = a1 a2
. ) is a constant. Therefore, we get:
V ∝√h
Knowing a1, a2 and g, the value of the constant k for a given apparatus (venturi meter) can be calculated once for all. Hence, V, the rate of flow of a liquid, can be determined by recording the value of h in the manometers.