Venturimeter: This device is used to measure velocities and mass rate of flow of liquid at the different cross-sections of a pipe. it consists of a constriction inserted in a pipe line and have tapers at the in let and outlet, so that turbulence is avoided. (See fig.)
Let at the cross-sectional areas A1 and A2, the velocities are v1 and v2 respectively.
From the equation of continuity,
A1v1 = A2v2
From Bernoulli's theorem,
