Laser Doppler anemometer

Abstract

Abstract The anemometer, which has two laser diodes (LD1, LD2), whose laser beams (1, 2) are concentrated into a specific region of a particle- containing flow (3) of a fluid in such a way as to produce a virtual interference fringe pattern in this region, and at least one photodetector (D1) for detecting light scattered by the flowing fluid, the wavelength of the laser diodes (LD1, LD2) being adjusted by a temperature and flow control (12, 13) and stabilised, permits testing of the sign (direction) of the flows (3) when the two laser diodes (LD1, LD2) are adjusted to different emission wavelengths and there is present for stabilising the differential frequency a control circuit (8, 9, 10) which acts on the temperature and/or current control (13) of at least one of the laser diodes (LD1, LD2).

Inventors

• 👤 Dietrich Dr. Dopheide
• 👤 Michael Faber
• 👤 Günter Taux
• 👤 Gerhard Reim

Bibliographic Details