High-speed time-resolved color schlieren visualization of shock wave phenomena

Shock Waves ◽  
2005 ◽  
Vol 14 (5-6) ◽  
pp. 333-341 ◽  
Author(s):  
H. Kleine ◽  
K. Hiraki ◽  
H. Maruyama ◽  
T. Hayashida ◽  
J. Yonai ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Time Resolved ◽  
Schlieren Visualization ◽  
Wave Phenomena

Mechanics of the influx phase in the jet regurgitant mode of a powered resonance tube

2019 ◽  
Vol 18 (2-3) ◽  
pp. 279-298 ◽  
Author(s):  
Bhavraj Thethy ◽  
David Tairych ◽  
Daniel Edgington-Mitchell
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Fluid Velocity ◽  
Velocity Variation ◽  
Shock Strength ◽  
Velocity Change ◽  
Resonator Length ◽  
Time Resolved ◽  
Reflected Waves ◽  
Shock Position

Time-resolved visualisation of shock wave motion within a powered resonant tube (PRT) is presented for the regurgitant mode of operation. Shock position and velocity are measured as functions of both time and space from ultra-high-speed schlieren visualisations. The shock wave velocity is seen to vary across the resonator length for both the incident and reflected waves. Three mechanisms are explored as explanations for the variation in velocity: change in local fluid velocity, variation in shock strength and variations in local temperature. For the incident wave, local fluid velocity and shock strength are extracted from the data and both are demonstrated to contribute to the observed variation, with a non-trivial remainder likely explained by variation in temperature.

Highly separated axisymmetric step shock-wave/turbulent-boundary-layer interaction

2017 ◽  
Vol 828 ◽  
pp. 236-270 ◽  
Author(s):  
Gaurav Chandola ◽  
Xin Huang ◽  
David Estruch-Samper
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Turbulent Boundary Layer ◽  
High Speed ◽  
Large Scale ◽  
Scale Separation ◽  
Time Resolved ◽  
Layer Interaction ◽  
Boundary Layer Interaction ◽  
High Reynolds

The unsteadiness of a shock-wave/turbulent-boundary-layer interaction induced by an axisymmetric step (cylinder/$90^{\circ }$-disk) is investigated experimentally at Mach 3.9. A large-scale separation of the order of previously reported incoming turbulent superstructures is induced ahead of the step ${\sim}30\unicode[STIX]{x1D6FF}_{o}$ and followed by a downstream separation of ${\sim}10\unicode[STIX]{x1D6FF}_{o}$ behind it, where $\unicode[STIX]{x1D6FF}_{o}$ is the incoming boundary-layer thickness. Narrowband high-frequency instabilities shift gradually to more moderate frequencies along the upstream separation region exhibiting a strong predominance of shear-induced disturbance levels – arising between the outer high-speed flow and the subsonic bubble. Through spectral/time-resolved analysis of this high Reynolds number and large-scale separation, results offer new insights into the shear layer’s inception and evolution (convection, growth and instability) and its influence on interaction unsteadiness.

Multiple Shock Waves and its Unsteady Characteristics in Internal Flows

2019 ◽  
Author(s):  
Jintu K. James ◽  
Heuy Dong Kim
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Flow Field ◽  
High Speed ◽  
Flow Characteristics ◽  
Wave Pattern ◽  
Time Resolved ◽  
Constant Area ◽  
Boundary Layer Interaction ◽  
Multiple Shock

Abstract Shock wave turbulent boundary layer interaction is a fundamental phenomenon observed in most of the gas dynamics applications such as wind tunnels, supersonic air intakes, transonic airfoil, nozzle flows, etc. The flow field and shock wave pattern in a constant area duct are analyzed experimentally. The focus of the present study is to present the time-resolved flow characteristics of the multiple shock waves and its oscillations. High-speed Schlieren flow visualization is used to capture the transient shock structure in the wind tunnel constant area test section. A gradient-based image processing was incorporated to capture the shock excursion details. Results indicate that the shock pattern is unsymmetrical in the flow field. The foot of the lambda shock wave in the upper and lower exhibit a difference in axial location and there is a large difference in this value at the mean position when the shock moves in the upstream direction compared to the downstream movement.

Detonation Studies in Dispersed Solid Particulate Explosives Using High Speed Time-Resolved Holography

1992 ◽  
Vol 296 ◽  
Author(s):  
Michael J. Ehrlich ◽  
James W. Wagner ◽  
Jacob Friedman ◽  
Heinrich Egghart
Keyword(s):  
Shock Wave ◽  
Convective Flow ◽  
High Speed ◽  
Liquid Fuel ◽  
Similar Case ◽  
Incident Shock ◽  
Solid Particles ◽  
Liquid Droplets ◽  
Time Resolved ◽  
Individual Particles

IntroductionClouds of dispersed explosive or combustible solid particles are detonable and such systems may exhibit self-sustained detonation [1–8]. However, the method by which individual particles in the explosive cloud interact to sustain detonation is not well understood. The similar case of liquid fuel/air explosives was investigated in detail during the 1960's and 1970's. For these systems, it was established that incident shock waves serve to shatter large liquid droplets into a mist of micro-droplets. These microdroplets are almost instantaneously accelerated to the convective flow velocity behind the shock wave. The energy released upon ignition of the micromist supports the shock wave and selfsustained detonation results [9–11].

Flow features resulting from shock wave impact on a cylindrical cavity

2007 ◽  
Vol 580 ◽  
pp. 481-493 ◽  
Author(s):  
BERIC W. SKEWS ◽  
HARALD KLEINE
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Shear Layers ◽  
Complex Flow ◽  
Wave Impact ◽  
Time Resolved ◽  
Additional Information ◽  
Flow Features ◽  
Time Resolved Imaging ◽  
The Impact

The complex flow features that arise from the impact of a shock wave on a concave cavity are determined by means of high-speed video photography. Besides additional information on features that have previously been encountered in specific studies, such as those relating to shock wave reflection from a cylindrical wall and those associated with shock wave focusing, a number of new features become apparent when the interaction is studied over longer times using time-resolved imaging. The most notable of these new features occurs when two strong shear layers meet that have been generated earlier in the motion. Two jets can be formed, one facing forward and the other backward, with the first one folding back on itself. The shear layers themselves develop a Kelvin–Helmholtz instability which can be triggered by interaction with weak shear layers developed earlier in the motion. Movies are available with the online version of the paper.

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