Processing of high-speed videos of shock wave boundary layer interactions

Abstract

This paper presents a framework for processing high-speed videos recorded during gas experiments in a shock tube. The main objective is to study boundary layer interactions of reflected shock waves in an automated way, based on image processing. The shock wave propagation was recorded at a frame rate of 500,000 frames per second with a Kirana high-speed camera. Each high-speed video consists of 180 frames, with image size [ $$768 \\times 924$$ 768 × 924 ] pixels. An image processing framework was designed to track the wave front in each image and thereby estimate: (a) the shock position; (b) position of triple point; and (c) shock angle. The estimated shock position and shock angle were then used as input for calculating the pressure exerted by the shock. To validate our results, the calculated pressure was compared with recordings from pressure transducers. With the proposed framework, we were able to identify and study shock wave properties that occurred within less than $$300\\, \\upmu \\hbox {sec}$$ 300 μ sec and to track evolveness over a distance of 100\xa0mm. Our findings show that processing of high-speed videos can enrich, and give detailed insight, to the observations in the shock experiments.