What type of meter is based on the Doppler effect?

The type of meter based on the Doppler effect is the ultrasonic meter. This type of meter operates by emitting high-frequency sound waves that travel through a fluid. When these sound waves encounter moving particles within the fluid, the frequency of the sound waves is altered based on the motion of the particles, which is a principle known as the Doppler effect.

By measuring the change in frequency of the reflected sound waves, the ultrasonic meter can determine the flow rate of the fluid. This allows it to provide a non-invasive and accurate method of flow measurement, making it suitable for various applications in fluid dynamics.

Mechanical meters, magnetic meters, and positive displacement meters operate on entirely different principles. Mechanical meters typically rely on moving mechanical parts to measure flow, magnetic meters use electromagnetic principles to measure the flow of conductive liquids, and positive displacement meters measure flow based on the volume of fluid moved through the meter. These alternative technologies do not utilize the Doppler effect, which is central to the functionality of ultrasonic meters.