Forward-Scattering Particle-Image Velocimetry

Forward-scattering particle-image velocimetry (FSPIV) is a technique for measuring velocities in microscopic flow fields as thin liquid films. As in other particle-image-velocimetry (PIV) techniques, the velocity of a flow is computed from temporally changing images of suitably illuminated, neutrally buoyant particles entrained in the flow. Unlike other PIV techniques, (1) particles are back-illuminated with coherent or partially coherent light, (2) a microscope is used to resolve forward scattering of light from the particles, and (3) all three components of velocity can be measured from only one line of sight, without readjustment of optics.