4 ms·
There's also the laser-based one which measures doppler shift in the backscatter of light passing through the air.
by porphyra 4y ago
There's also the laser-based one which measures doppler shift in the backscatter of light passing through the air.
- klysm 4y agoOf light?? How fast does the air have to be moving or do your sensors have to be?
- porphyra 4y agoIt doesn't have to be very fast. Doppler shift causes the return signal to be a different wavelength which can be accurately detected interferometrically even if the shift is very small.
- walterbell 4y agoLight interacting with particles in the air, https://ntrs.nasa.gov/api/citations/19910009744/downloads/19910009744.pdf https://ntrs.nasa.gov/api/citations/19910009744/downloads/19... > A laser anemometer measures fluid velocity indirectly by determining the speed of particles moving through the flow field. These particles, which may be occurring naturally or introduced artificially into the flow, must be sufficiently small so that they follow the flow closely. If this is the case, then the fluid velocity can be equated to the measured particle velocity.