AkustikDopplerströmungsmessern

AkustikDoppler refers to the family of techniques that use the acoustic Doppler effect to measure velocity in fluids. It relies on transmitting an acoustic signal into a moving medium and detecting the frequency shift of the returning signal caused by scattering from suspended particles or roughness. The measured Doppler shift is proportional to the velocity component along each acoustic beam, with the geometry described by the beam angle to the flow.

Modern implementations often use multiple beams to reconstruct a velocity vector or produce a vertical profile of speed and direction. Acoustic Doppler currents profilers (ADCPs) and Doppler velocimeters are common examples.

Typical transducers operate in water with frequencies from tens to hundreds of kilohertz, while air applications use higher frequencies; c denotes the sound speed in the medium. Data are obtained as ranges or depths (range gates) and are processed to yield time-averaged velocity fields.

Applications include oceanography, river hydrology, and industrial flow measurements, as well as laboratory experiments such as wind tunnels and spray flows.

Limitations include the requirement for sufficient particle seeding or scatterers, aliasing at high velocities, angular dependence, and signal attenuation in turbid or highly attenuating media.

Origin traces to the Doppler effect described by Christian Doppler in 1842; practical water velocity measurement using acoustic methods expanded in the late 20th century.

Overall, AkustikDoppler provides non-contact, non-intrusive velocity measurements with good temporal resolution, but requires attention to calibration, geometry, and scene seeding.