Hot-film/hot-wire anemometer calibration for low velocities using image processing

Calibration of hot-wire and hot-film probes at low velocities is a difficult task because the dynamic pressure at these velocities is quite low and may not be easily measured. To solve this problem, substituent techniques have been presented in the literature that rely on other phenomena and utilize different hardware. This study described a simple and low-cost method which proposes moving the anemometer probe in the quiescent air (here by means of a swinging arm) and tracked this motion with a camera. After processing the images, the time history of the probe velocity was measured by numerical calculations. Calibration curve was, then, obtained without any predetermined relationship. Using a medium-speed video camera, which is often found in laboratories, would obviate the need for a position sensor and a complicated arm on which this sensor is mounted. This technique can be used for not only pendulums but also other means of moving probes in a quiescent medium. (C) 2021 Sharif University of Technology. All rights reserved.