As early as 1738, the Swiss scientist Daniel Bernoulli utilized the differential pressure method-based on the first Bernoulli equation-to measure water flow. Later, the Italian G.B. Venturi investigated the use of the Venturi tube for flow measurement and published his findings in 1791.
In 1886, the American Clemens Herschel applied the Venturi tube principle to create a practical device for measuring water flow.
From the early to mid-20th century, established measurement principles gradually matured; researchers no longer confined their thinking to existing methods but instead embarked on new avenues of exploration.
By the 1930s, methods for measuring the flow velocity of liquids and gases using acoustic waves began to emerge. However, little significant progress was made in this field prior to World War II; it was not until 1955 that the Maxson flowmeter-which employed the acoustic circulation method-was introduced for the purpose of measuring aviation fuel flow.
From the 1960s onward, flow measurement instrumentation began to evolve toward greater precision and miniaturization.
With the rapid advancement of integrated circuit technology, ultrasonic flowmeters incorporating phase-locked loop technology gained widespread adoption. Furthermore, the extensive application of microcomputers significantly enhanced flow measurement capabilities; for instance, the integration of microcomputers into Laser Doppler Velocimeters enabled the processing of more complex signals.