Optical diagnostics, a specialism of TOSQAN
For measuring droplet velocity:Laser Doppler Velocimetry (LDV)Particle Image Velocimetry (PIV)
For measuring droplet size:
out-of-focus imaging (interferometrics laser imaging for droplet sizing (ILIDS)), which is used to measure diameter by analyzing the interference fringes created by the interaction of a laser and a droplet. See video below.
For measuring droplet temperature:
For measuring concentrations of gases:
Spontaneous Raman Scattering (SRS) spectrometry, which uses the inelastic interaction between an incident photon from the laser and a polyatomic molecule.
Other measurements performed
Gases: concentration, temperature (K), velocity, turbulence, pressure
Droplets: diameter, velocity, temperature
Aerosols: diameter, concentration