Palma Technology기술연구소기술정보
Laser Doppler Velocimeter

The LDV interprets the interference pattern created when two laser beams reflect off of a target particle to determine the velocity of the particle.

The interference pattern incorporates the Doppler phase shift of both laser beams and so can determine the particle's velocity very accurately.

LDV techniques have many advantages. The among the most important is that no material probe is used, so the flow is not disturbed.

Additionally, no velocity calibration is necessary, the velocity components of the target particle are precisely measured, and the measurement is taken over a very small area so changes in fluid flows over an area can be more precisely measured.

While LDV has many advantages, there are some limitations.

If there are no bubbles or particulate impurities in the fluid which the lasers can target, then particles must be introduced into the flow.

The accuracy of the measurement itself is dependent on the assumption that any particles in the fluid stream are moving with the same velocity as the fluid at that point (which may not be true if the particles are significantly denser than the fluid or of significant size relative to the areas being measured).

The other major limitation is that the laser beams must have an optically clear path to the target particle and back to the sensors.

If this is not possible, than any readings acquired are erroneous.