The alternating color image anemometry and its application

Abstract

In this study, the alternating color image anemometry (ACIA) method is proposed. Alternating color, multiexposure particle image is recorded by a three-chip color CCD camera. Because the red, blue, and green CCD chips of a 3-CCD camera have different sensitivities to the color of scattered light, the alternating color, multiexposure particle image can be separated into sequential images using appropriate band processes. The magnitude and direction of the velocity vectors can then be determined from the sequential images. The ACIA method thus preserves the merits of both PIV and DPIV methods by analyzing a multiexposure particle image using sequential image files. The proposed ACIA method is then calibrated by measuring the velocity field of a constant speed rotating disk and an empty channel flow. Satisfactory results are obtained.