3次元画像処理流速計による乱流気流計測

概要

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A three-dimensional particle tracking velocimeter for turbulent air flow measurement was developed. As a tracer particle, spherical plastic capsules and He-filled bubbles were tested. The plastic capsule's traceability was anticipated to be insufficient for high-frequency components of turbulence because its density was thirty times larger than that of air, its diameter was small enough compared with the turbulent microscale, and the image was clear enough to track. On the other hand, the bubble, which was neutrally buoyant, had a relatively large diameter and its image had two peaks in brightness. The previous 3-D PTV system was modified so that two successive instantaneous particle images could be recorded on two successive TV fields with an arbitrary time interval. In order to evaluate the present technique, a fully developed turbulent air flow in a square-cross-section duct was measured. Cross-stream distributions of the mean velocities and of the full Reynolds stress tensor components were obtained and some of them were compared with a separate hot-wire measurement. The agreement was generally good for both tracers. However, part of the plastic particles adhered to the bottom wall of the duct and caused serious errors in the measurement.
一般社団法人日本機械学会の論文
1994-03-25