Behavior and flow mechanism of shock train self-excited oscillation influenced by background waves

Hou, Wenxin; Chang, Juntao; Xie, Zongqi; Wang, Youyin; Wu, Linke; Bao, Wen

doi:10.1016/j.actaastro.2019.09.032

Cited by 29 publications

(15 citation statements)

References 30 publications

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“…However, the structures and mean positions of the shock train during self-excited oscillation are different when the throttling ratio is different. In our previous study on shock train selfexcited oscillation influenced by background waves, three different oscillation modes were found (Hou et al, 2020). The histories of the flap angle and corresponding throttling ratio are shown in Fig.…”

Section: Cause Of the Asymmetrical Structure Of The Shock Trainmentioning

confidence: 92%

“…A high-speed camera with a frame rate of 2500 Hz was used to record the shock train motion. Other details of the test facility can be found in our previous study (Hou et al, 2020).…”

Section: Experimental Facility and Measurement Methodologymentioning

confidence: 99%

“…The background waves in the isolator, caused by the wedge installed before the isolator entrance (Hou et al, 2020), are shown in Fig. 5.…”

Section: Background Waves In the Isolatormentioning

confidence: 99%

“…In our previous study on shock train self-excited oscillation influenced by background waves, three oscillation modes were observed, distinguishable by the distribution of the wall pressure standard deviation. Self-excited oscillation affected by background waves was compared with oscillation unaffected by background waves (Hou et al, 2020). However, our previous study did not discuss in detail the underlying fundamental flow mechanism, which is the focus of this study.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study and analysis of shock train self-excited oscillation in an isolator with background waves

Hou

Chang

Kong

et al. 2020

J. Zhejiang Univ. Sci. A

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A study of shock train self-excited oscillation in an isolator with background waves was implemented through a wind tunnel experiment. Dynamic pressure data were captured by high-frequency pressure measurements and the flow field was recorded by the high-speed Schlieren technique. The shock train structure was mostly asymmetrical during self-excited oscillation, regardless of its oscillation mode. We found that the pressure discontinuity caused by background waves was responsible for the asymmetry. On the wall where the pressure at the leading edge of the shock train was lower, a large separation region formed and the shock train deflected toward to the other wall. The oscillation mode of the shock train was related to the change of wall pressure in the oscillation range of its leading edge. The oscillation range and oscillation intensity of the shock train leading edge were affected by the wall pressure gradient induced by background waves. When located in a negative pressure gradient region, the oscillation of the leading edge strengthened; when located in a positive pressure gradient region, the oscillation weakened. To find out the cause of self-excited oscillation, correlation and phase analyses were performed. The results indicated that the instability of the separation region induced by the leading shock was the source of perturbation that caused self-excited oscillation, regardless of the oscillation mode of the shock train.

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Section: Cause Of the Asymmetrical Structure Of The Shock Trainmentioning

confidence: 92%

“…A high-speed camera with a frame rate of 2500 Hz was used to record the shock train motion. Other details of the test facility can be found in our previous study (Hou et al, 2020).…”

Section: Experimental Facility and Measurement Methodologymentioning

confidence: 99%

“…The background waves in the isolator, caused by the wedge installed before the isolator entrance (Hou et al, 2020), are shown in Fig. 5.…”

Section: Background Waves In the Isolatormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental study and analysis of shock train self-excited oscillation in an isolator with background waves

Hou

Chang

Kong

et al. 2020

J. Zhejiang Univ. Sci. A

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“…The large-eddy 3D analysis in the area of uniform cross-section with a low aspect ratio rectangular duct geometry is studied. [18][19][20][21][22] In Reference [23], experimental investigations are conducted on scramjet combustor to study the influence of oscillation modes and the impact of instability in the separation zone is reported. In Reference [24], a numerical investigation on a scramjet combustor is conducted to study the influence of forced oscillations and it is reported that different waves have the ability to influence the oscillation but are incapable of changing the frequency.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic investigation of the shock train in a scramjet with the effects of backpressure and divergent angles

Gugulothu

2020

Heat Trans

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Numerical simulations are carried out to study the effect of divergence angle and adverse pressure gradient on the movement of a shock wave train in a scramjet isolator. The commercial software tool ANSYS Fluent 16 was used to simplify the two-dimensional Reynolds-averaged Navier-Stokes equation with the compressible fluid flow by considering the densitybased solver with the standard k-ε turbulence model. The species transport model with a single-step volumetric reaction mechanism is employed. Initially, the simulated results are validated with experimental results available in the open literature. The obtained results show that the variation of the divergence angle and backpressure on the scramjet isolator has greater significance on the flow field. Also, with an increase in the backpressure, due to the intense turbulent combustion, the shock wave train developed should expand along the length and also move towards the leading edge of the isolator leading to a rapid rise in the pressure so that the pressure at the entrance of the isolator can match the enhanced backpressures.

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Effects of back pressure perturbation on shock train oscillations in a rectangular duct

Sethuraman

Kim

2021

Acta Astronautica

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Behavior and flow mechanism of shock train self-excited oscillation influenced by background waves

Cited by 29 publications

References 30 publications

Experimental study and analysis of shock train self-excited oscillation in an isolator with background waves

Experimental study and analysis of shock train self-excited oscillation in an isolator with background waves

Aerodynamic investigation of the shock train in a scramjet with the effects of backpressure and divergent angles

Effects of back pressure perturbation on shock train oscillations in a rectangular duct

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