Video: Story of shock-vortex interaction during compressible vortex ring and trailing jet impingement on a cone

In many industrial applications, a permeable mesh (porous screen) is used to control the unsteady (most commonly vortex) flows. Vortex flows are known to display intriguing behavior while propagating through porous screens. This numerical study aims to investigate the effects of physical properties such as porosity, Reynolds number, inlet flow dimension, and distance to the screen on the flow behavior. The simulation model includes a piston-cylinder vortex ring generator and a permeable mesh constructed by evenly arranged rods. Two methods of user-defined function and moving mesh have been applied to model the vortex ring generation. The results show the formation, evolution, and characteristics of the vortical rings under various conditions. The results for vorticity contours and the kinetic energy dissipation indicate that the physical properties alter the flow behavior in various ways while propagating through the porous screens. The numerical model, cross-validated with the experimental results, provides a better understanding of the fluid–solid interactions of vortex flows and porous screens.

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A comparative study on the evolution of compressible vortex ring generated from a short driver section shock tube

Fluid Dynamics Research ◽

10.1088/1873-7005/abb09a ◽

2020 ◽

Vol 52 (5) ◽

pp. 055504

Author(s):

Santanu Dey ◽

T Murugan ◽

Dipankar Chatterjee

Keyword(s):

Comparative Study ◽

Shock Tube ◽

Vortex Ring ◽

Driver Section ◽

Compressible Vortex Ring

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Compressible starting jet: pinch-off and vortex ring–trailing jet interaction

Journal of Fluid Mechanics ◽

10.1017/jfm.2017.128 ◽

2017 ◽

Vol 817 ◽

pp. 560-589 ◽

Cited By ~ 17

Author(s):

Juan José Peña Fernández ◽

Jörn Sesterhenn

Keyword(s):

Reynolds Number ◽

Shear Layer ◽

Vortex Ring ◽

Pressure Ratio ◽

Reynolds Numbers ◽

Chamber Pressure ◽

Vortex Interaction ◽

Dominant Feature ◽

Chamber Temperature ◽

Starting Jet

The dominant feature of the compressible starting jet is the interaction between the emerging vortex ring and the trailing jet. There are two types of interaction: the shock–shear layer–vortex interaction and the shear layer–vortex interaction. The former is clearly not present in the incompressible case, since there are no shocks. The shear layer–vortex interaction has been reported in the literature in the incompressible case and it was found that compressibility reduces the critical Reynolds number for the interaction. Four governing parameters describe the compressible starting jet: the non-dimensional mass supply, the Reynolds number, the reservoir to unbounded chamber temperature ratio and the reservoir to unbounded chamber pressure ratio. The latter parameter does not exist in the incompressible case. For large Reynolds numbers, the vortex pinch-off takes place in a multiple way. We studied the compressible starting jet numerically and found that the interaction strongly links the vortex ring and the trailing jet. The shear layer–vortex interaction leads to a rapid breakdown of the head vortex ring when the flow impacted by the Kelvin–Helmholtz instabilities is ingested into the head vortex ring. The shock–shear layer–vortex interaction is similar to the noise generation mechanism of broadband shock noise in a continuously blowing jet and results in similar sound pressure amplitudes in the far field.

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