Question

Describe an experiment for which both LDV(laser doppler velocimetry) and pulsed wire anemometry would be suitable but HWA(hot wire anemometers) would not.
Also give an example of an experiment for which pulsed wire anemometry would be preferable to LDV.

Answer 1

Since HWA is insensitive to flow reversals, their use in highly turbulent flows are limited. Hence for experiments with highly turbulent flows LDV and pulse wire are suitable but HWA is not. Turbulent flow may be seen with wind tunnel experiments for missiles and fighter aircrafts, cars etc.

The measuring volume of pulse wire anemometer is much smaller than LDA. This means that pulse wire can be placed very near the wall. Hence pulse wire anemometers are preferred for measurements at or near turbulent separating flow regions.