Hilbert-diagnostics of vortex rings induced in air by a pressure pulse on a hole

Abstract

Formation and evolution of complementary vortical rings induced in air by a pressure pulse on a hole under various boundary conditions are investigated by Hilbert-optics methods and computer modeling. It is experimentally demonstrated that reverse ring-shaped vortices inside the chamber after its depressurization are formed not only in the case with a reduced initial pressure in the chamber as compared with the ambient atmospheric pressure but also in the case with a higher gas pressure in the chamber than the atmospheric pressure. The complementary vortex rings propagating in forward and reverse directions might significantly affect the combustion process in the jets.

Hydrodynamic Vortex Structures in a Diffusion Jet Flame

“…It offers a large variety of modern methods and techniques: shadowgraphy and Schlieren methods [11][12][13], laser Doppler anemometry [13,14], Doppler technologies of velocity field measurements [15,16], and particle image velocimetry [17]. The Hilbert diagnostics of flows [18][19][20][21] based on visualization of space-and-time phase disturbances induced in the light field by the flow passing through the examined medium has a high potential for development and application. Such disturbances are visualized by means of the Hilbert filtration of the optical field, transforming the latter into a Hilbert-conjugate signal.…”