Hysteresis behavior of shock train driven by continuous incoming Mach number variation in an isolator with background waves

Wang, Ziao; Xin, Xuanan; Guo, Jifeng; Yue, Lianjie; Kong, Chen; Huang, Renzhe; Chang, Juntao

doi:10.1016/j.euromechflu.2023.04.013

Cited by 3 publications

(1 citation statement)

References 43 publications

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“…Its primary function is to decelerate the incoming supersonic flow from the intake and to prevent the back-propagation of disturbances from the combustor to the inlet [3]. Extensive research has been dedicated to understanding the complex flow structures and mechanisms within the isolator [4][5][6], which are crucial for optimizing scramjet engine design and developing effective flow control strategies [7][8][9]. However, the aeroelastic challenges associated with the isolator have not received as much attention, despite their significant implications for the development of future hypersonic vehicles [10,11].…”

Section: Introductionmentioning

confidence: 99%

Fluid–Structure Interactions between Oblique Shock Trains and Thin-Walled Structures in Isolators

Meng,

Zhao,

Wang

et al. 2024

Aerospace

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Understanding aeroelastic issues related to isolators is pivotal for the structural design and flow control of scramjets. However, research on fluid–structure interactions (FSIs) between thin-walled structures and the isolator flow remains limited. This study delves into the FSIs between thin-walled panels and the isolator flow, as characterized by an oblique shock train, by quantitatively analyzing 11 flow parameters assessing the structural response, separation zones, shock structures, flow symmetry, and performance. The results reveal that an FSI triggers panel flutter under oblique shock train conditions, with the panel shapes exhibiting a combination of first- and second-mode responses, peaking at 0.75 of the panel length. Compared to rigid wall conditions, isolators with a flexible panel at the bottom wall experience downstream movement of the separation zones and shock structures, reduced flow symmetry, and minor changes in performance. Transient fluctuations occur due to the panel flutter. Two flexible panels at the top and bottom walls have a comparatively lesser influence on the averaged parameters but exhibit more violent transient fluctuations. Furthermore, the FSI effects under oblique shock train conditions are contrasted with those under normal shock train conditions. The flutter response under normal shock train conditions is more pronounced, with a larger amplitude and higher frequency, driven by the heightened participation of the first-mode response. The effects of FSIs under normal shock train conditions on the averaged parameters are the opposite (with a larger influence) to those under oblique shock train conditions, with significantly more drastic transient fluctuations. Overall, this study sheds light on the complex and substantial influence of FSIs on the isolator flow, emphasizing the necessity of considering FSIs in future isolator design and development endeavors.

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Section: Introductionmentioning

confidence: 99%

Fluid–Structure Interactions between Oblique Shock Trains and Thin-Walled Structures in Isolators

Meng,

Zhao,

Wang

et al. 2024

Aerospace

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Start/unstart hysteresis characteristics driven by embedded rocket of a rocket-based combined-cycle inlet

Yang,

Tian,

Yang

et al. 2024

Physics of Fluids

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The RBCC (rocket-based combined-cycle) engine integrates a rocket engine into the flow passage of the ramjet engine, thereby significantly broadening the operating range and becoming one of the potential solutions for the reusable space transportations. The embedded rocket, as one of the core components of an RBCC engine, is strongly coupled to other components, such as the inlet and combustor, and can induce significant impacts on the inlet start behaviors. For the stable operation of the RBCC inlet, the start/unstart hysteresis characteristics and the reliable start boundaries driven by embedded rocket are experimentally and numerically studied. The results show that due to the function of embedded rocket jet, the inlet start/unstart hysteresis range of Mach number rises from Mach 1.79–1.87 to 1.85–1.90, and the back pressure hysteresis range changes from Pc/P∞ of 3.9–5.8 to 4.7–5.8. Meanwhile, during the increasing and decreasing process of the embedded rocket pressure, the inlet undergoes a transition between start and unstart, accompanied by hysteresis phenomena as well. Furthermore, three different control strategies are proposed for the start of RBCC inlet. Similar to the traditional ramjet inlets, the RBCC inlet can self-/re-start by reducing the back pressure. Particularly, owing to the synergistic effect of embedded rocket jet and back pressure, the RBCC inlet can self-/re-start by reducing the embedded rocket pressure from Procket/P∞ = 58 to 39 in the “embedded rocket dominated” cases, while the inlet self-/re-start can be achieved by increasing the rocket pressure from Procket/P∞ = 20 to 39 in the “back pressure dominated” cases.

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Closed-Loop Control of Dynamic Oblique Shock with Arc Plasma

Liu,

Wang,

Huang

et al. 2024

AIAA Journal

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The fluctuations caused by the dynamic shock wave and its interaction with the boundary layer bring formidable challenges for aerodynamic design and stable control of supersonic aircraft. The mechanism of closed-loop control for dynamic oblique shock stabilizing with arc plasma is numerically studied. Two types of dynamic oblique shocks are formed in supersonic airflow by a compression ramp rotation and incoming Mach number variation, respectively. A closed-loop controller is established to connect the arc plasma deposited power with the pressure ratio across the dynamic shock by using the proportional-integral method. It realizes the shock pressure ratio stabilized in the desired target value with a local overshoot appearing at the initial excitation and a more stable flow downstream of the oblique shock during excitation state for both types of dynamic shock control. The effects of arc plasma length and ramp rotating speed on the closed-loop control for the dynamic shocks induced by ramp rotation are further discussed. Results show that the arc plasma with longer length is more favorable to the dynamic oblique shock control with lower energy consumption and total pressure loss. The pressure ratio fluctuation is increased at higher ramp rotation speed, but its standard deviation is still limited to 0.3% of the desired target value during excitation state.

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Hysteresis behavior of shock train driven by continuous incoming Mach number variation in an isolator with background waves

Cited by 3 publications

References 43 publications

Fluid–Structure Interactions between Oblique Shock Trains and Thin-Walled Structures in Isolators

Fluid–Structure Interactions between Oblique Shock Trains and Thin-Walled Structures in Isolators

Start/unstart hysteresis characteristics driven by embedded rocket of a rocket-based combined-cycle inlet

Closed-Loop Control of Dynamic Oblique Shock with Arc Plasma

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