The interaction of a shock wave with the boundary layer in a reflected shock tunnel

1989 ◽  
Vol 10 (6) ◽  
pp. 545-552
Author(s):  
Xu Li-gong
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Shock Tunnel ◽  
Reflected Shock

Three-dimensional instantaneous structure of a shock wave/turbulent boundary layer interaction

2009 ◽  
Vol 622 ◽  
pp. 33-62 ◽  
Author(s):  
R. A. HUMBLE ◽  
G. E. ELSINGA ◽  
F. SCARANO ◽  
B. W. van OUDHEUSDEN
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Turbulent Boundary Layer ◽  
High Speed ◽  
Large Scale ◽  
Three Dimensional ◽  
Reflected Shock Wave ◽  
Layer Interaction ◽  
Reflected Shock ◽  
Boundary Layer Interaction

An experimental study is carried out to investigate the three-dimensional instantaneous structure of an incident shock wave/turbulent boundary layer interaction at Mach 2.1 using tomographic particle image velocimetry. Large-scale coherent motions within the incoming boundary layer are observed, in the form of three-dimensional streamwise-elongated regions of relatively low- and high-speed fluid, similar to what has been reported in other supersonic boundary layers. Three-dimensional vortical structures are found to be associated with the low-speed regions, in a way that can be explained by the hairpin packet model. The instantaneous reflected shock wave pattern is observed to conform to the low- and high-speed regions as they enter the interaction, and its organization may be qualitatively decomposed into streamwise translation and spanwise rippling patterns, in agreement with what has been observed in direct numerical simulations. The results are used to construct a conceptual model of the three-dimensional unsteady flow organization of the interaction.

scholarly journals Two-dimensional unsteadiness map of oblique shock wave/boundary layer interaction with sidewalls

2019 ◽  
Vol 871 ◽  
Author(s):  
P. K. Rabey ◽  
S. P. Jammy ◽  
P. J. K. Bruce ◽  
N. D. Sandham
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Low Frequency ◽  
Oblique Shock ◽  
Oblique Shock Wave ◽  
Pressure Measurements ◽  
Wave Boundary Layer ◽  
Reflected Shock ◽  
Separation Shock ◽  
Wave Boundary

The low-frequency unsteadiness of oblique shock wave/boundary layer interactions (SBLIs) has been investigated using large-eddy simulation (LES) and high-frequency pressure measurements from experiments. Particular attention has been paid to off-centreline behaviour: the LES dataset was generated including sidewalls, and experimental pressure measurements were acquired across the entire span of the reflected shock foot. The datasets constitute the first maps of low-frequency unsteadiness in both streamwise and spanwise directions. The results reveal that significant low-frequency shock motion (with $St\approx 0.03$) occurs away from the centreline, along most of the central separation shock and in the corner regions. The most powerful low-frequency unsteadiness occurs off-centre, likely due to the separation shock being strengthened by shocks arising from the swept interactions on the sidewalls. Both simulation and experimental results exhibit asymmetry about the spanwise centre. In simulations, this may be attributed to a lack of statistical convergence; however, the fact that this is also seen in experiments is indicative that some SBLIs may exhibit some inherent asymmetry across the two spanwise halves of the separation bubble. There is also significant low-frequency power in the corner separations. The relation of the unsteadiness in the corner regions to that in the centre is investigated by means of two-point correlations: a key observation is that significant correlation does not extend across the attached flow channel between the central and corner separations.

scholarly journals Processing of high-speed videos of shock wave boundary layer interactions

2020 ◽  
Author(s):  
Samee Maharjan ◽  
Dag Bjerketvedt ◽  
Ola Marius Lysaker
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Image Processing ◽  
High Speed ◽  
Frame Rate ◽  
Image Size ◽  
Pressure Transducers ◽  
Reflected Shock ◽  
Shock Position ◽  
Wave Boundary

Abstract This paper presents a framework for processing high-speed videos recorded during gas experiments in a shock tube. The main objective is to study boundary layer interactions of reflected shock waves in an automated way, based on image processing. The shock wave propagation was recorded at a frame rate of 500,000 frames per second with a Kirana high-speed camera. Each high-speed video consists of 180 frames, with image size [$$768 \times 924$$ 768 × 924 ] pixels. An image processing framework was designed to track the wave front in each image and thereby estimate: (a) the shock position; (b) position of triple point; and (c) shock angle. The estimated shock position and shock angle were then used as input for calculating the pressure exerted by the shock. To validate our results, the calculated pressure was compared with recordings from pressure transducers. With the proposed framework, we were able to identify and study shock wave properties that occurred within less than $$300\, \upmu \hbox {sec}$$ 300 μ sec and to track evolveness over a distance of 100 mm. Our findings show that processing of high-speed videos can enrich, and give detailed insight, to the observations in the shock experiments.

ON THE GASDYNAMIC MECHANISMS OF EXOTHERMIC REACTION WAVE FORMATION BEHIND SHOCK WAVES

2020 ◽  
Author(s):  
A. Kiverin ◽  
◽  
I. Yakovenko ◽  
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Gas Flow ◽  
Exothermic Reaction ◽  
Incident Shock ◽  
Incident Shock Wave ◽  
Wave Formation ◽  
Mixture Flow ◽  
Reflected Shock ◽  
Reaction Wave

The paper analyzes the gasdynamic evolution of the test mixture flow in the shock tube at the stage prior to reaction start. The numerical analysis clearly shows that the incepience of reaction kernels is associated with the specific features of flow development in the boundary layer behind an incident shock wave. It is shown that similar to the processes in the gas flow near a solid surface, the gasdynamic instability arises and develops in the flow behind a shock wave. The linear stage of instability development determines the formation of roll-up vortices at a certain distance behind the shock front. Further, at the nonlinear stage, these roll-up vortices transform in more complex structures that diffuse into the bulk flow. Evolution of vortices causes temperature redistribution on the scales of the boundary layer. On the one hand, there is a certain heating due to the kinetic energy dissipation. On the other hand, there are heat losses to the wall. As a result, the temperature field near the wall becomes nonuniform. The reflected shock amplifies temperature perturbations when interacts with the developed boundary layer. This mechanism determines the formation of hot kernels in which the reaction starts. So, the localized sites of exothermal reaction are arising providing conditions for reaction wave formation and propagation in the precompressed test gas.

Numerical simulation of the interaction between reflected shock wave and near-wall boundary layer

2007 ◽  
Vol 33 (2) ◽  
pp. 173-175 ◽  
Author(s):  
S. V. Bulovich ◽  
V. É. Vikolaĭnen ◽  
S. V. Zverintsev ◽  
R. L. Petrov
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Shock Wave ◽  
Reflected Shock Wave ◽  
Reflected Shock ◽  
Wall Boundary Layer ◽  
Wall Boundary ◽  
Near Wall
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