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Shock tube

About: Shock tube is a research topic. Over the lifetime, 6963 publications have been published within this topic receiving 99372 citations.


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TL;DR: In this paper, the interaction of a shock train with a normal suction slot is presented and the structure and pressure recovery within the shock train is analyzed by means of Schlieren images and wall pressure measurements.
Abstract: The interaction of a shock train with a normal suction slot is presented. It was found that when the pressure in the suction slot is smaller or equal to the static pressure of the incoming supersonic flow, the pressure gradient across the primary shock is sufficient to push some part of the near wall boundary layer through the suction slot. Due to the suction stabilized primary shock foot, the back pressure of the shock train can be increased until the shock train gradually changes into a single normal shock. During the experiments, the total pressure and therewith the Reynolds number of the flow were varied. The structure and pressure recovery within the shock train is analysed by means of Schlieren images and wall pressure measurements. Because the boundary layer is most important for the formation of a shock train, it has been measured by a Pitot probe. Additionally, computational fluid dynamics is used to investigate the shock boundary-layer interaction. Based on the experimental and numerical results, a simplified flow model is derived which explains the phenomenology of the transition of a shock train into a single shock and derives distinct criteria to maintain a suction enhanced normal shock. This flow model also yields the required suction mass flow in order to obtain a single normal shock in a viscous nozzle flow. Furthermore, it allows computation of the total pressure losses across a normal shock under the influence of boundary-layer suction.

40 citations

Journal ArticleDOI
01 Jan 2009
TL;DR: In this article, a planar detonation wave traveling in an initiation tube was transmitted into a test section where a combustible high speed flow was induced by an incident shock wave generated in a shock tube.
Abstract: The initiation and propagation of detonation waves in combustible high speed flows were studied experimentally. A planar detonation wave traveling in an initiation tube was transmitted into a test section where a combustible high speed flow was induced by an incident shock wave generated in a shock tube. In this study, the flow Mach numbers were obtained as 0.9 and 1.2. The experimental results show that depending on the flow velocity, the apparent propagation velocity of a detonation wave is higher in the upstream and lower in the downstream direction than the CJ velocity. Smoked plate records reveal cellular patterns deformed in the flow direction, and the calculated aspect ratios of the cell were found to agree well with the experimental ones on the basis of the assumption that the velocity of the transverse wave is not affected by the flowing mixture. By analyzing the shock-wave diffraction at the position where there is an abrupt change in the area, on the basis of Whitham’s theory, it was deduced that in the present experimental set-up, the detonation was initiated by the reflection of the diffracted shock waves on the sidewalls of the test section. The agreement between the experimental and calculated results regarding the position of the cellular patterns on the smoked plate record indicated that the position of detonation initiation in high speed flows is shifted downstream due to the flow velocity.

40 citations

Journal ArticleDOI
TL;DR: In this paper, the splitting of a single liquefaction shock wave into a vapor phase forerunner and a following condensation shock is observed photographically in shock tube experiments and the behavior of the two-shock system is qualitatively described by equilibrium shock conditions, but the state downstream of the forerunner shock is found to be far from equilibrium.
Abstract: The splitting of a single liquefaction shock wave into a vapor‐phase forerunner shock and a following condensation shock is observed photographically in shock‐tube experiments. The behavior of the two‐shock system is qualitatively described by equilibrium shock conditions, but the state downstream of the forerunner shock is found to be far from equilibrium. It is proposed that this state is limited by the critical supersaturation for homogeneous nucleation. The overall pressure jump for the two‐shock system is much greater than would be predicted by an equilibrium calculation.

40 citations

Journal ArticleDOI
TL;DR: A laser-based concept for an air mass flux sensor based on the simultaneous measurement of density and velocity of O(2) using wavelength modulation absorption spectroscopy in an AlGaAs laser diode combined with second-harmonic detection is presented.
Abstract: We present a laser-based concept for an air mass flux sensor based on the simultaneous measurement of density and velocity of O(2). The sensor uses wavelength modulation absorption spectroscopy at 10 MHz of an AlGaAs laser diode in the b(1)Sigma(g)(+)(v' = 0)-X(3)Sigma(g)(-)(v'' = 0) system of O(2), combined with second-harmonic detection. The apparatus is demonstrated on a high-speed oxygen flow generated behind the incident shock wave in a shock tube. The measurement time is 0.5 ms for typical absorption levels of 0.5%.

40 citations

Journal ArticleDOI
TL;DR: In this article, the pyrolysis of acetylene was investigated behind reflected shock waves in a single-pulse shock tube over the temperature range from 1000 to 1670 K. The major products were 1-buten-3-yne, 1,3-butadiyne, and hydrogen.
Abstract: The pyrolysis of acetylene was investigated behind the reflected shock waves in a single-pulse shock tube over the temperature range from 1000 to 1670 K. The major products were 1-buten-3-yne, 1,3-butadiyne, and hydrogen. The main primary C4 product, however, changes from 1-buten-3-yne to 1,3-butadiyne with the increase of temperature. At the lower temperatures the formation of 1-buten-3-yne dominates the pyrolysis of acetylene. The rate of 1-buten-3-yne formation is second order with respect to acetylene concentration, and its second-order rate constant is expressed as follows: k(cm^3 mol^-1s^-1)=10^14.39±0.26exp((-46400±1400)/RT) The isotopic distribution of 1-buten-3-yne in the pyrolysis of the equimolar C2H2 and C2D2 mixture, proved that the pyrolysis proceeds via a free-radical mechanism. A free-radical chain mechanism initiated by the bimolecular reaction of acetylene, 2C2H2→C4H3+H, was proposed.

40 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023148
2022285
2021134
2020175
2019173
2018159