SEMICONDUCTOR-LASER DOPPLER ANEMOMETER FOR APPLICATIONS IN AERODYNAMIC RESEARCH

Using a laser diode as the light source and an avalanche photodiode as the detector, an anemometry system has been developed that is particularly suitable to applications in aerodynamic research. This device consumes significantly less power than a conventional laser Doppler anemometer system and may easily be operated with the electrical power available in an airplane during flight. It is also very small in size and may be conveniently transported and mounted at places where space is limited, such as an aircraft wing. The hardware of a semiconductor laser Doppler anemometer unit is described in this paper. The performance of the system is evaluated theoretically as well as experimentally. Measurements in boundary layers are presented to demonstrate that a well-optimized semiconductor laser Doppler anemometer system is as reliable as a conventional system based on a gas laser and a photomultiplier tube.