Experimental characteristics of oblique shock train upstream propagation

Wang, Chengpeng; Xue, Longsheng; Tian, Xuang

doi:10.1016/j.cja.2017.02.004

Cited by 34 publications

(10 citation statements)

References 25 publications

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“…In these studies, researchers usually use mechanical throttling of the flow to simulate combustion-driven high-backpressure. The results of these studies prove the effectiveness of the experimental method based on the mechanical throttling system, and reproduce the flow characteristics during the unstart process well [14][15][16]. These studies revealed that the downstream backpressure increase from the flow-throttling device choked the flow in the inlet-isolator.…”

Section: Introductionsupporting

confidence: 65%

“…The experiments were conducted in the hypersonic wind tunnel of Nanjing University of Aeronautics and Astronautics [16] (NHW, Figure 4) with a freestream Mach number M ∞ = 6. The wind tunnel is a blow-down facility.…”

Section: Experimental Apparatus and Proceduresmentioning

confidence: 99%

“…The rising backpressure chokes the inlet flow and forms upstream propagating disturbances as an unstart shock train system [13][14][15]. The unstart shock train system, which involves an interaction between the duct's peripheral boundary layer and the central shock wave field, usually appears in constant or nearly constant cross-sectional area supersonic/hypersonic duct flows [15][16][17]. To contain the unstart shock train system caused by the downstream pressure rise from combustion, an isolator portion of a scramjet engine is a constant-area duct located between the engine inlet and the combustor section.…”

Section: Introductionmentioning

confidence: 99%

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Correlation Analysis of Separation Shock Oscillation and Wall Pressure Fluctuation in Unstarted Hypersonic Inlet Flow

et al. 2019

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The flow field in a hypersonic inlet model at a design point of M = 6 has been studied experimentally. The focus of the current study is to present the time-resolved flow characteristics of separation shock around the cowl and the correlation between the separation shock oscillation induced by the unstart flow and the wall pressure fluctuation when the inlet is in a state of unstart. High-speed Schlieren flow visualization is used to capture the transient shock structure. High-frequency pressure transducers are installed on the wall around both the cowl and isolator areas to detect the dynamic pressure distribution. A schlieren image quantization method based on gray level detection and calculation is developed to analyze the time-resolved spatial structure of separation shock. Results indicate that the induced separation shock oscillation and the wall pressure fluctuation are closely connected, and they show the same frequency variation characteristics. The unsteady flow pattern of the “little buzz” and “big buzz” modes are clarified based on time-resolved Schlieren images of separation shock. Furthermore, the appropriate location of the pressure transducers is determined on the basis of the combined analysis of fluctuating wall-pressure and oscillating separation shock data.

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Section: Introductionsupporting

confidence: 65%

Section: Experimental Apparatus and Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Correlation Analysis of Separation Shock Oscillation and Wall Pressure Fluctuation in Unstarted Hypersonic Inlet Flow

et al. 2019

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“…15,16 All the shock waves composing the shock train assume an inclined configuration, leading to a flow pattern called an oblique shock train. 17 The numerous variables which contribute to generating a complicated interaction between the shocks and the boundary layer make a comprehensive analysis of the flow field extremely difficult. Understanding the flow physics in the presence of the interaction of multiple shock waves with the boundary layer in internal flows is particularly challenging but essential to develop methods to predict and control the shock train.…”

Section: Introductionmentioning

confidence: 99%

Effect of back-pressure forcing on shock train structures in rectangular channels

et al. 2018

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“…Wang et al. 20 experimentally investigated the structure and dynamics of an oblique shock train in a duct model and found that the oblique shock train propagated more rapidly when the leading edge of the oblique shock train encounters the separation bubble. Xu et al.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of shock train unsteady movement in a mixing duct

Lü

Wang

Yan

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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The structure and dynamic of the shock train in a mixing duct are investigated experimentally in a supersonic air breathing wind tunnel. High-speed schlieren technique and pressure measurements are utilized for the data acquisition. Nozzle clapboards are applied to separate the incoming flow into upper secondary flow, primary flow, and lower secondary flow. The Mach number of all incoming flows is 2.05, whereas the static pressures between primary and secondary flow stay unmatched. Experimental results indicate that nozzle clapboards lead to complex background waves and mixing layers in the mixing duct. As the throttling valve rotates at a constant speed, two motion patterns alternatively govern the shock train movement, namely jump movement and slow movement. Judging from the path of shock train leading edges, adverse pressure gradient at the wall of background flow induces jump movement, while the slow movement only appears at the zone of favorable pressure gradient. Besides, leading shock structures continuously change in the forward propagation process. Four types of leading shock structures are discovered namely regular reflection, convex-stem Mach reflection, straight-stem Mach reflection, and concave-stem Mach reflection. Based on the numerical results of the background flow field, these special structures are explained theoretically by analyzing the variation of the wavefront Ma contour lines.

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Experimental characteristics of oblique shock train upstream propagation

Cited by 34 publications

References 25 publications

Correlation Analysis of Separation Shock Oscillation and Wall Pressure Fluctuation in Unstarted Hypersonic Inlet Flow

Correlation Analysis of Separation Shock Oscillation and Wall Pressure Fluctuation in Unstarted Hypersonic Inlet Flow

Effect of back-pressure forcing on shock train structures in rectangular channels

Experimental investigation of shock train unsteady movement in a mixing duct

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