As early as 1738, the Swiss scientist Daniel Bernoulli measured water flow using the differential pressure method based on the first Bernoulli equation. Later, the Italian scientist G.B. Venturi studied the use of the Venturi tube to measure flow and published his results in 1791.
In 1886, the American Herschel developed the Venturi tube into a practical measuring device for water flow.
From the early to mid-20th century, the original measurement principles gradually matured, and people no longer limited their thinking to existing methods but began new explorations.
In the 1930s, methods for measuring the flow velocity of liquids and gases using sound waves emerged. While methods for measuring flow using sound waves were explored, they did not make significant progress until World War II. It wasn't until 1955 that the Maxson flow meter, using the acoustic circulation method, was introduced for measuring the flow rate of aviation fuel.
From the 1960s onwards, measuring instruments began to develop towards precision and miniaturization.
With the rapid development of integrated circuit technology, ultrasonic flow meters with phase-locked loop technology have been widely used. The widespread application of microcomputers has further improved the flow measurement capability. For example, laser Doppler velocimeters can process more complex signals after being equipped with microcomputers.