Partnermanagement: Kanomax

Measurement of fluid velocity

A Laser-Doppler-Velocimeter (LDV) measures fluid velocity by utilizing coherence of laser light. It detects the Doppler shift frequency of the scattering light of particles in the fluid and calculates the velocity of the particles (fluid). With an LDV system, non-intrusive measurements without disturbing the measuring object, liquid, or gas flow, are achieved. No calibration is necessary and reverse flow measurements at a high resolution are also possible.

The Smart LDV III system is a high-quality and compact system, provides the absolute velocity value of the flow velocity with high repeatability and is applicable to complicated flow fields as it is independent from flow temperature and media.

Technical data

Flow velocity range-40 m / s…260 m / s (f = 400 mm, Smart LDV III with frequency shifter)
LaserLD λ=660 nm, 60 mW
Focal length f (for air)150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm
Measuring surface0,13 mm x 1,3 mm (f=200 mm)
Measurement methodBackward scattering / forward scattering (optional)
Sensor sized=61 mm x 345 mm


  • Aerodynamic and hydrualic property measurement, e.g. in wind tunnels
  • Measurement requiring high time-resolution
  • Velocity measurement in fuel cell or stacks
  • Comparison with CFD (Computational Fluid Dynamics)
  • PIV accuracy tests
  • Applicable to complicated flow fields, such as combustion fields since it is minimally affected by temperature and media

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