3D-flow measurements in micro channel and pipe with high time resolution using micro digital-holographic particle-tracking velocimetry

A micro digital-holographic particle-tracking velocimetry (micro-DHPTV) method for high time-resolution flow field measurement in a micro-channel was developed by Satake et al. (2005). The system consists of an objective lens, a high-speed camera and a single high-frequency double pulsed laser. Particle positions in a three-dimensional field can be reconstructed by a computer-generated hologram. The time evolution of a three-dimensional water flow in a semicircular micro-channel of 100-$\mu$m width and 40-$\mu$m depth and in a circular micro-pipe of 100-$\mu$m inner diameter are obtained successfully using this micro-DHPTV system. The three- dimensional measurement volume of the system is 410 $\mu$m $\times$ 100 $\mu$m $\times$ 40 $\mu$m and is irradiated by one laser beam with the time resolution of 100 $\mu$sec and a reputation rate of 1 kHz. Consequently, 130 velocity vectors in the semicircular micro-channel can be obtained instantaneously. Satake, S., Kunugi, T., Sato, K., Ito T., Taniguchi, J., ``Three- dimensional flow tracking in a micro channel with high time resolution using micro digital-holographic particle-tracking velocimetry,'' To appear in Optical Review, 2005.