Animations analysis in experimental fluid dynamics

Abstract

Digital imaging became one of the main tools for studying fluid dynamics. Modern high-speed cameras support video recording at high frame rates which allows studying of the extended high-speed processes. We demonstrate here different animations based on various methods of visualization, such as water temperature evolution with a frame rate of 115 Hz; high-speed shadowgraph visualization of different flows – supersonic water jet formation process (100 000 frames/s), shadowgraph animations of the shock waves created by the pulsed discharges (124 000 frames/s). Also, as an example of the plasma radiation emission technique, we offer 9 sequential images of the pulse gas discharge visualization obtained by the high-speed CCD camera with the 100 ns delay between frames. We used a commercial and developed in-house software based on machine vision and learning techniques for automatic flow animations processing. The examples of the automatic bow shock and oblique shock detection using Canny edge detection and Hough transform on the pre-trained convolutional neural network are provided and discussed.