How PIV Works

Particle Image Velocimetry is a remarkably powerful technique for measuring fluid flow, stress, strain and shear.

Accurate planar flow measurement

The technique relies on a planar beam of light - a light sheet - usually from a laser. The laser light sheet illuminates particles entrained in a flow. Pairs of images are captured using a high-speed digital camera. PIV software computes how far the particles moved between the two images and a velocity map is generated.

Advanced yet simple

Particle Image Velocimetry has developed to the point where it is now a very commonly used technique in many industrial and research sectors where instantaneous full-field velocity vector maps are required. Oxford Lasers VisiVector systems are designed to be easy to setup and simple to use. VidPIV, our PIV software features an intuitive interface that lets you quickly see how the measurements are being calculated and enables complex analysis to be carried out with ease.

Micro PIV

Small scale PIV differs in technique from the standard experimental configuration because of the difficulty in focussing light sheets into small areas. Furthermore, since small scale measurements often involve micro-fluidic devices and small flow-channels, a great deal of laser light can be scattered into the camera which will degrade the data quality that can be delivered.

In micro systems the flow is seeded with fluorescent powder which is viewed through a filter to block the large amounts of scattered laser light. In combination with high-magnification lenses, accurate small scale measurements can be made on almost any micro-fluidic device.