Focusing of a shock wave in a rarefied gas

Kowalczyk, Piotr; Płatkowski, Tadeusz; Waluś, Włodzimierz

doi:10.1007/s001930050181

Cited by 8 publications

(5 citation statements)

References 3 publications

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“…These flow patterns have not yet been investigated and only the transverse shock waves have been visualized in the experiment via Schlieren photography. The interaction between obstacles and shock waves has been the subject of many studies on shock reflection in inert flows (see Izumi, Aso & Nishida 1994;Gelfand et al 2000;Kowalczyk, Płatkowski & Waluś 2000;Ben-Dor 2007;Skews & Kleine 2007;Taieb, Ribert & Hadjadj 2010;Shadloo, Hadjadj & Chaudhuri 2014, and references therein) and also in the context of detonation establishment of Mach stems and detonation re-initiation (see Bhattacharjee et al 2013). In contrast to these studies, the amplitude of the wavy wall in the present numerical study is so small that the focusing phenomenon is limited to producing an increase of pressure in the concave part of the wall, which can be considered as a shallow reflector (Kowalczyk et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Direct numerical simulation of shock wavy-wall interaction: analysis of cellular shock structures and flow patterns

2016

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Section: Introductionmentioning

confidence: 99%

Direct numerical simulation of shock wavy-wall interaction: analysis of cellular shock structures and flow patterns

2016

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“…Because the sinusoidal wavy wall with small amplitude is like a shallow cavity [37], a lot of post-shock gas gathers in the focal region when the shock wave collides with it. The vorticity contour maps in x-y plane at M 1 = 1.5 and 2.5 are shown in Fig.…”

Section: Vortex Structurementioning

confidence: 99%

Comparative analysis of flow behind a normal shock wave reflected off a wavy end-wall at different Mach numbers and wave amplitudes

2021

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The interaction between an incident shock wave and a wavy end-wall in a three-dimensional geometry is numerically simulated by using a high-order finite-difference solver with a ghost-cell immersed boundary method. The aim is to discover the differences of the unsteady propagation characteristics of triple bifurcation points and transverse waves at different incident shock Mach numbers (M 1 ) and wavy wall amplitudes (A ww ). For a benchmark case with M 1 = 1.5 and A ww = 1 mm, the simulated results are in a good agreement with other studies, indicating the reliability of the current simulation technique. The numerical results at M 1 = 1.5, 1.9, 2.5, and 3.5 show that the Mach numbers of the transverse shock waves issued from the triple bifurcation points decrease with time according to a power function. It indicates that the deformation of the shock wave attenuates with time and its flat shape is gradually recovered. The stronger the incident shock wave is, the faster the deformation decays. In the central region, a petal-like vortex structure is observed near the wavy wall and its advancing speed with periodic fluctuation correlates with the cycle of the transverse motion of the triple bifurcation point. With the increase of M 1 , the petal-like vortex gradually grows up in size, and a faster rate can be observed in the normal direction. By comparing the propagation characteristics of transverse waves at different wavy wall amplitudes, it is discovered that the cellular pattern becomes more diverse as the wall amplitude increases. This is due to the multiple collisions of the transverse waves on the wavy wall, which leads to the multi-modal waves system in the shocked gas.

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“…Shugaev et al 5 observed the generation of jet and eddy in the focusing experiments with the gases of CF 4 and CCl 2 F 2 . Kowalczyk et al 6 made numerical simulation about the planar shock focus process in the cavity with the inert gases. The numerical results showed that only if the cavity was deep enough, the shape of cavity would have obvious effect on the shock wave focusing.…”

Section: Introductionmentioning

confidence: 99%

The influence of incident shock Mach number on radial incident shock wave focusing

Chen

Tan

et al. 2016

AIP Advances

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Experiments and numerical simulations were carried out to investigate radial incident shock focusing on a test section where the planar incident shock wave was divided into two identical ones. A conventional shock tube was used to generate the planar shock. Incident shock Mach number of 1.51, 1.84 and 2.18 were tested. CCD camera was used to obtain the schlieren photos of the flow field. Third-order, three step strong-stability-preserving (SSP) Runge-Kutta method, third-order weighed essential non-oscillation (WENO) scheme and adaptive mesh refinement (AMR) algorithm were adopted to simulate the complicated flow fields characterized by shock wave interaction. Good agreement between experimental and numerical results was observed. Complex shock wave configurations and interactions (such as shock reflection, shock-vortex interaction and shock focusing) were observed in both the experiments and numerical results. Some new features were observed and discussed. The differences of structure of flow field and the variation trends of pressure were compared and analyzed under the condition of different Mach numbers while shock wave focusing.

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Focusing of a shock wave in a rarefied gas

Cited by 8 publications

References 3 publications

Direct numerical simulation of shock wavy-wall interaction: analysis of cellular shock structures and flow patterns

Direct numerical simulation of shock wavy-wall interaction: analysis of cellular shock structures and flow patterns

Comparative analysis of flow behind a normal shock wave reflected off a wavy end-wall at different Mach numbers and wave amplitudes

The influence of incident shock Mach number on radial incident shock wave focusing

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