Shock wave-induced vortex loops emanating from nozzles with singular corners

Abstract

The focus of the current study is to examine experimentally the diffracted shock wave pattern and the consequent vortex loop formation, propagation, and decay from nozzles having singular corners.Non-intrusive qualitative and quantitative techniques: schlieren, shadowgraphy, and particle image velocimetry (PIV) are employed to analyse the induced flow fields. Eye-shaped nozzles were used with the corner joints representing singularities. The length of the minor axes are a = 6 and 15 mm, with the major axis b = 30 mm for both cases. The experiments are performed for flow Reynolds numbers in the range 0.8 ×10 5 and 4.6 ×10 5 . Air is used in both driver and driven sections of the shock tube.

Shock wave diffraction in the presence of a supersonic co-flow jet

“…A Toepler Z-type schlieren photography configuration identical to that used by Zare-Behtash et al [20] was employed in the present study. A continuous light beam emitted by a 450 W Xenon arc lamp passes through a condenser lens with a 79 mm focal length and a slit before being collimated by a parabolic mirror of 203.3 mm diameter and 1016 mm focal length.…”

Experimental Investigation of Impinging Shock – Cavity Interactions with Upstream Transverse Jet Injection

“…A TSI six-jet atomiser TSI model 9307-6 was used to create seeder particle with particle diameters of approximately 1µm [18]. A LaVision Imager ProX2M CCD camera with The recorded image pairs are initially divided into 32×32 pixel interrogation windows and then processed with a cross correlation algorithm using the DaVis 7.2 software.…”

Time-resolved quantitative visualization of complex flow field emitted from an open ended shock tube using a wavefront measuring camera

“…When shock wave is discharged from a ST to the ambience it creates an unsteady complex flow field that includes expansion and diffraction of shock followed by formation of shear layer and vortices, the formation of embed shock, trailing jet, Kelvin-Helmholtz flow instabilities etc. Other than these mentioned aftereffects shock tubes have also been employed to study interactions among shocks, shock-body, shock-vortex 14-7-15, 20-09-17, 09-02-18 structures [6][7][8][9][10] and generated acoustic noise [11] due to these interactions, leapfrogging phenomenon of vortex rings [12], effect on out coming flow due to exit shape of nozzles [9,10,[13][14][15] and many more.…”