Dopplersebességmérés

Dopplersebességmérés, often translated as Doppler velocimetry, is a technique used to measure the velocity of a moving object or fluid by analyzing the Doppler shift of reflected or transmitted waves. This phenomenon, named after Austrian physicist Christian Doppler, occurs when the source of a wave and an observer are in relative motion. The frequency of the wave perceived by the observer changes depending on whether the source is moving towards or away from them. If the source is moving towards the observer, the perceived frequency increases (blueshift), and if it's moving away, the perceived frequency decreases (redshift).

In Doppler velocimetry, a wave, typically sound or electromagnetic radiation like microwaves or light, is directed at a moving target. A portion of this wave is reflected back to a receiver. By comparing the frequency of the transmitted wave with the frequency of the received wave, the Doppler shift can be calculated. This shift is directly proportional to the radial velocity of the target – its speed along the line of sight between the transmitter/receiver and the target.

This technique has wide-ranging applications. In meteorology, Doppler radar is used to measure wind speeds and detect storm systems. In medicine, Doppler ultrasound is crucial for imaging blood flow, assessing heart function, and diagnosing vascular diseases. Automotive applications include radar-based cruise control and speed detection for traffic enforcement. Industrial uses involve monitoring fluid flow in pipes and measuring the speed of moving machinery. The accuracy of Doppler velocimetry depends on factors such as the wavelength of the wave used, the angle of incidence, and the stability of the target's motion.