Three-Dimensional Measurement of High-Speed Air Flow by High-Speed Cameras and DP Matching Method

Abstract

Dynamic programming matching technique, which is commonly used for the voice recognition, has been adapted to the time line images obtained by the spark tracing method for the high-speed air flow. As the high voltage sparks between two electrodes trace the air flow very well, we can measure the two or three-dimensional air velocities, if we can quantify the displacement and the time interval between sparks. In order to capture the three-dimensional profiles of each spark, the authors have utilized two synchronized high-speed cameras at different viewing angles. Thus each spark is captured in a separate frame. With the dynamic programming matching technique, the characteristics of the two consecutive spark lines are correctly corresponded and thus the three-dimensional displacements between sparks are quantified. Presently, the flow field of a high-speed air jet was measured and thus the applicability of this technique has been proved.