Interaction between a shock wave and a longitudinal low-density gas layer

Georgievskii, P. Yu.; Левин, В. А.; Sutyrin, O. G.

doi:10.1134/s0015462816050148

Cited by 7 publications

(1 citation statement)

References 3 publications

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“…The presence of the core of transverse inhomogeneity in supersonic flow similar to the local minimum of the Mach number is the well-known cause of the development of a precursor in the form of a separation structure projected upstream in the zone of intersection of the shock wave and the core of inhomogeneity [19]. The corresponding time-dependent analog is the appearance of a precursor ahead of the shock front propagating along the local reduced-density channel in a gas at rest [20]. Penetration of the precursor into the near-wake region behind the lattice element leads to the formation of an extended subsonic channel (Fig.…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

Hysteresis in Supersonic Flow Past a Plane Cascade of Cylindrical Rods

Guvernyuk

Maksimov

2021

Fluid Dyn

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Abstract— The results of numerical simulation of the interaction of supersonic flow with a permeable screen in form of an infinite plane cascade (lattice) of circular cylinders are given. The interaction regime in which the shocks ahead of the cylinders are localized on the scale of the cascade step is considered. The multi-block computational technique in which the viscous boundary layers are resolved by means of local grids using the Navier–Stokes equations, while the effects of inteferrence between the shock-wave structures in supersonic wake are described within the framework of Euler’s equations. The action of shock waves induced by the neighboring elements of lattice to the near-wake region behind the intermediate elements can ambiguously affect the aerodynamic lattice performance as well as generate time-dependent phenomena in the wake. The flow regimes are classified depending on continuous increase and decrease in the free-stream supersonic air flow in the Mach number range from 2.4 to 4.2 with reference to the lattice of the 80% permeability. The sources of the hysteresis behavior of the lattice aerodynamic drag with respect to the Mach number and the mechanisms of the onset of self-oscillating wake flow regimes are discussed.

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Section: Discussion Of the Resultsmentioning

confidence: 99%

Hysteresis in Supersonic Flow Past a Plane Cascade of Cylindrical Rods

Guvernyuk

Maksimov

2021

Fluid Dyn

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Plane blast wave interaction with an elongated straight and inclined heat-generated inhomogeneity

2018

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The unstable evolution of an elongated elliptically shaped inhomogeneity that is embedded in ambient air and aligned both normal and at an angle to an incident plane blast wave of impact Mach number 2.15 is investigated both experimentally and numerically. The elliptic inhomogeneities and the blast waves are generated using gas heating and exploding wire technique and their interaction is captured optically using shadowgraph method. While two symmetric counter-rotating vortices due to Richtmyer–Meshkov instability are observed for the straight interaction, the formation of a train of vortices similar to Kelvin–Helmholtz instability, introducing asymmetry into the flow field, are observed for an inclined interaction. During the early phase of the interaction process in the straight case, the growth of the counter-rotating vortices (based on the sequence of images obtained from the high-speed camera) and circulation (calculated with the aid of numerical data) are found to be linear in both space and time. Moreover, the normalized circulation is independent of the inhomogeneity density and the ellipse thickness, enabling the formulation of a unique linear fit equation. Conversely, the circulation for an inclined case follows a quadratic function, with each vortex in the train estimated to move with a different velocity directly related to its size at that instant. Two factors influencing the quadratic nature are identified: the reduction in strength of the transmitted shock thereby generating vortices with reduced vorticity, along with the gradual loss of vorticity of the earlier-generated vortices.

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