DEFINITION:

Conventional measuring techniques mostly rely upon strain gauges and temperature sensors.

Non intrusive optical measuring techniques are able to visualise the flow structure and to provide quantitative data relative to both surface characteristics (pressure distribution, transition detection, etc.) and flow field properties
(mainly velocity and turbulence).

(Source: ACARE Domain 109)

SUBDOMAINS:

1. Pressure: (un)steady pressures, Pitot/multihole probes, PSP (Pressure Sensitive Paints).
2. Temperature and heat flux: Infrared Thermography, thermocouples, hot wire, hot film.
3. Velocity: LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry), DGV (Doppler Global Velocimetry).
4. Flow visualisation: Schlieren technique, shadowgraphy, laser tomoscopy, Rayleigh scattering, interferometry.
5. Surface visualisation: oil film, mini-tufts, infrared or sublimation transition detection.
6. Forces, moments: strain-gage balances (6-component or local loads).
7. Model attitude/deformation: potentiometers, accelerometers, photogrammetry, moiré.