Laser-Doppler Profile Sensor for Spatially High Resolved Velocity Measurement of Shear Flows.

Laser-Doppler profile sensor was developed for highly spatially resolved velocity-profile measurement of shear flows. The profile sensor utilizes two optical fringe systems in the measurement volume. The sensor resolves both the position and the velocity of individual tracer particle inside the measurement volume. Hence the spatially high resolved velocity profile is obtained without traversing the sensor. In this paper, the sensor systems based on two different techniques are reported. The sensors were designed to measure flow velocity close to zero, which is encountered in boundary layer flows. The spatial resolution and relative accuracy were estimated to be about 5 micrometers and 0.2 %, respectively. The dimensions of the measurement volume were approximately 0.1 x 0.1 x 1 mm. The sensors were tested in laminar boundary layers and they successfully resolved the Blasius velocity profile close to the wall. Furthermore, the turbulent boundary layer in a two-dimensional channel flow was analyzed. The feasibility of the sensors was demonstrated through the experiments. [ABSTRACT FROM AUTHOR]