How Pitot tube is used in flow measurement?

Pitot tubes also utilize the principles captured in Bernoulli’s equation, to measure flow. Most pitot tubes actually consist of two tubes. One, the lowpressure tube measures the static pressure in the pipe. The second, the high-pressure tube is inserted in the pipe in such a way that the flowing fluid is stopped in the tube. The pressure in the high-pressure tube will be the static pressure in the system plus a pressure dependant on the force required stopping the flow.

Pitot tubes are more common measuring gas flows that liquid flows. They suffer from a couple of problems.

The pressure differential is usually small and hard to measure. The differing flow velocities across the pipe make the accuracy depends on the flow profile of the fluid and the position of the pitot in the pipe.