Abstract
Development of a portable and easy use LDV system is attempted. In order to miniaturize the system, a small Nd:YVO_4 solid laser is adopted as the laser light source. Noise performance of the laser whether to be able for the LDV system was check by the light detector measurement and a high speed analog-digital converter. The laser has strong noise in the range of 100 kHz to 3 MHz appearing nonperiodically. To avoid this noise, the laser frequency is shifted by the Bragg Cell so that the Doppler frequency is out of the high noise region. A prototype of the LDV system with the Nd:YVO_4 laser was build as one package module. This systems was tested for velocity measurements in both the rotating solid disk and a laminar two-dimensional channel flow. The tests confirm that the LDV system works well for the mean velocity measurement. This result suggests the large possibility to develop the portable LDV system.
