10 results on '"Longsheng Xue"'
Search Results
2. An integration method based on a novel combined flow for aerodynamic configuration of strutjet engine
- Author
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Longsheng Xue, Chengpeng Wang, Cheng Chuan, and Keming Cheng
- Subjects
Physics ,Shock wave ,0209 industrial biotechnology ,Mechanical Engineering ,Aerospace Engineering ,02 engineering and technology ,Aerodynamics ,Mechanics ,Conical surface ,01 natural sciences ,010305 fluids & plasmas ,Physics::Fluid Dynamics ,Boundary layer ,symbols.namesake ,020901 industrial engineering & automation ,Flow (mathematics) ,Mach number ,0103 physical sciences ,symbols ,Potential flow ,Wind tunnel - Abstract
In this paper a novel design method of aerodynamic configuration is proposed to integrate forebody, strut and inlet for strutjet engine, and a model at design point of Mach number 6 is generated to investigate the aerodynamic performance by both simulations and experiments. The basic flow field employed by proposed method is a combined flow named IBB, which is combined by Internal Conical Flow A (ICFA), truncated Busemann flow I (BI) for external section, and truncated Busemann flow II (BII) for internal section. The model configuration is generated by streamline tracing method from basic flow field, in which the forebody section is traced from ICFA and BI flows, and the inlet as well as strut section is traced from BII flow. The simulations in Mach number 4, 5, and 6 demonstrate uniform starting flow fields with relatively high total pressure recovery, which agree well with experiments in wind tunnel. Additionally, in low Mach number cases, this inlet could start at Mach number 3 while it is unstarted at Mach number 2.7; in high Mach number cases, a uniform flow could still exist in Mach number 6.5 while a relatively strong shock wave boundary layer interaction is found in cowl area of Mach number 7 case, indicating the inlet designed by proposed method works in a relatively wide Mach number range.
- Published
- 2021
3. A study on the RR-to-MR transition of shock wave reflections near the leading edge in hypersonic flows
- Author
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Longsheng Xue, Keming Cheng, and Chengpeng Wang
- Subjects
Shock wave ,Physics ,Leading edge ,Hypersonic speed ,business.product_category ,Shock (fluid dynamics) ,Mach reflection ,Mechanical Engineering ,Reynolds number ,Mechanics ,Condensed Matter Physics ,01 natural sciences ,Wedge (mechanical device) ,010305 fluids & plasmas ,symbols.namesake ,Mach number ,Mechanics of Materials ,0103 physical sciences ,symbols ,010306 general physics ,business - Abstract
In this paper, the incident shock–separation shock interactions on a surface plate near the leading edge are studied theoretically and experimentally, and the transition from regular reflection (RR) to Mach reflection (MR) is the main focus. The theoretical method employs free interaction theory (FIT) and the minimum entropy production (MEP) principle to analyse the separation shock strength of flow separated from the boundary layer and separated from the leading edge, respectively, the criterion based on the MEP principle is employed to predict the RR-to-MR transition near the leading edge. The experiments were performed on a rotatable wedge situated over a sharp leading-edge plate such that the wedge could continuously change the flow deflection angle from by means of a high-precision control device. Fast-response transducers and a high-speed camera were used to measure dynamic pressures and to take schlieren images, respectively. The influences of wedge positions, Reynolds numbers and Mach numbers on shock reflections are investigated by careful tests. The theoretical and experimental results for Mach numbers 5, 6, 7 and 8 show good agreement, indicating that the theoretical method is applicable.
- Published
- 2021
4. Novel Inducement to Unstart of a Parallel Modular Hypersonic Inlet
- Author
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Longsheng Xue, Chengpeng Wang, and Keming Cheng
- Subjects
020301 aerospace & aeronautics ,geography ,geography.geographical_feature_category ,business.product_category ,business.industry ,Flow (psychology) ,Aerospace Engineering ,Rocket-based combined cycle ,02 engineering and technology ,Static pressure ,Unstart ,Inlet ,01 natural sciences ,010305 fluids & plasmas ,Adverse pressure gradient ,Flow conditions ,0203 mechanical engineering ,Rocket ,0103 physical sciences ,Environmental science ,Aerospace engineering ,business - Abstract
The parallel modular inlet is a common configuration in a strutjet engine of the rocket-based combined-cycle hypersonic vehicle. To study the flow interaction between two adjacent inlets, the flowf...
- Published
- 2019
5. Theoretical study on regular reflection of shock wave–boundary layer interactions
- Author
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Zhiwei Shi, Bas van Oudheusden, Chengpeng Wang, Longsheng Xue, Keming Cheng, and Ferry Schrijer
- Subjects
Physics ,Shock wave ,boundary layer separation ,Mechanical Engineering ,Regular polygon ,Shock strength ,Ranging ,shock waves ,Mechanics ,Condensed Matter Physics ,01 natural sciences ,Wedge (geometry) ,010305 fluids & plasmas ,Flow separation ,Boundary layer ,symbols.namesake ,Mach number ,Mechanics of Materials ,0103 physical sciences ,symbols ,high-speed flow ,010306 general physics - Abstract
In this paper the configurations of shock wave-boundary layer interactions (SWBLI) are studied theoretically and experimentally in Mach number 2 and 2.5 flows on test models with various wedge angles ranging from to. The proposed theoretical method couples the free interaction theory (FIT) with the minimum entropy production (MEP) principle to predict the appearance of separation shock, resulting in convex, straight and concave separation shock waves according to different solution combinations, which agree well with current experiments. Additionally, several influences on SWBLI are studied experimentally, in which the parameters related to theoretical solutions are found mostly determining the flow configuration, and SWBLI is much more sensitive to incident shock strength than incoming flow properties. Separation could be suppressed by incident shock when the MEP solution is smaller than the FIT, while it could be intensified when the MEP solution is larger than FIT; by contrast, the effects of separation position and model mounting height could be very weak.
- Published
- 2020
6. Application of the minimum entropy production principle to shock reflection induced by separation
- Author
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Longsheng Xue, Keming Cheng, and Chengpeng Wang
- Subjects
Physics ,Mechanics of Materials ,Mechanical Engineering ,0103 physical sciences ,Separation (aeronautics) ,Reflection (physics) ,Mechanics ,010306 general physics ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,Minimum entropy ,Shock (mechanics) - Abstract
In this paper separation-induced shock reflection is studied theoretically and experimentally. An analytical model is proposed to establish the connections among upstream conditions, downstream conditions and shock configurations. Furthermore, the minimum entropy production principle is employed to determine the incident shock angles as well as the criterion for the transition from regular reflection to Mach reflection, which agrees well with experimental results. Additionally, a solution path for a reflected shock that fulfills the minimum entropy production principle is found in the overall regular reflection domain, based on which the steadiest shock configuration may be determined according to upstream and downstream conditions.
- Published
- 2018
7. Unsteady behavior of oblique shock train and boundary layer interactions
- Author
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Longsheng Xue, Cheng Chuan, Keming Cheng, and Chengpeng Wang
- Subjects
Physics ,020301 aerospace & aeronautics ,Astrophysics::High Energy Astrophysical Phenomena ,Aerospace Engineering ,Perturbation (astronomy) ,02 engineering and technology ,Mechanics ,01 natural sciences ,010305 fluids & plasmas ,Physics::Fluid Dynamics ,Boundary layer ,symbols.namesake ,Amplitude ,0203 mechanical engineering ,Shock position ,Particle image velocimetry ,Mach number ,Schlieren ,0103 physical sciences ,symbols ,Oblique shock - Abstract
The aim of present investigation is to analyze the unsteady oblique shock train and boundary layer interactions during the self-excited and forced oscillation. The oblique shock train is generated in a Mach 2.7 ducted flow and controlled by a downstream elliptical shaft. Cyclic rotating of the shaft leads to the forced oscillation. A Schlieren system as well as transient pressure measurements and particle image velocimetry have been used to capture quantitative and qualitative shock structure information. Results show that the behaviors of unsteady SBLIs structure are highly related to the dynamics of shock motion. For both self-excited oscillation and forced oscillation, the asymmetrical characteristics of first X-shock was found to be negatively correlated with shock velocity. There exist some relative motions between the first X-shock and the second shock, but the absolute variations are very weak. At lower excitation frequency, the relative motion is not noticeable to the oscillation amplitude, it could be treated as a rigid motion in the duct. At higher excitation frequency, the relative motion amplitude is significant to the oscillation amplitude, and the relative movement of shock cells becomes the dominant motion. There is a hysteretic effect and phase lag between the shock position and downstream pressure perturbation when the shock train travels along a different path for upstream and downstream movements, and the hysteretic effect becomes weaker with increasing frequency.
- Published
- 2018
8. Dynamic Characteristics of Separation Shock in an Unstarted Hypersonic Inlet Flow
- Author
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Keming Cheng, Longsheng Xue, and Chengpeng Wang
- Subjects
020301 aerospace & aeronautics ,Materials science ,Shock (fluid dynamics) ,Flow (psychology) ,Separation (aeronautics) ,Aerospace Engineering ,02 engineering and technology ,Mechanics ,Static pressure ,01 natural sciences ,Pressure coefficient ,Pressure sensor ,010305 fluids & plasmas ,Data acquisition ,Flow conditions ,0203 mechanical engineering ,0103 physical sciences - Published
- 2018
9. Shock Oscillation and Pressure Fluctuation in Unstarted Hypersonic Inlet Flow
- Author
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Zhao Junqi, Chengpeng Wang, Keming Cheng, Jiao Yun, and Longsheng Xue
- Subjects
Materials science ,Shock (fluid dynamics) ,Oscillation ,Flow (psychology) ,Hypersonic inlet ,Mechanics - Published
- 2017
10. Preliminary Integrated Design of Hypersonic Vehicle Configurations Including Inward-Turning Inlets
- Author
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Chengpeng Wang, Keming Cheng, Xuang Tian, Lingfeng Yan, and Longsheng Xue
- Subjects
Integrated design ,Engineering ,business.industry ,Mechanical Engineering ,Flow (psychology) ,Hypersonic flight ,Aerospace Engineering ,Aerodynamics ,Propulsion ,Physics::Fluid Dynamics ,Cross section (physics) ,Drag ,Airframe ,General Materials Science ,Aerospace engineering ,business ,Civil and Structural Engineering - Abstract
A design method employed for preliminary integration of a hypersonic vehicle airframe configuration with its propulsion flow path is described. This method is primarily based on the integration of the variable cross section inward-turning inlet and the airframe. Three typical configurations include lifting body, sim-waverider, and semi-axisymmetric cone. Rectangular-to-circular, erose-to-circular, and sector-to-circular shape transition Busemann inlets are designed to integrate these three vehicle bodies, respectively. The results of numerical simulations show that the aerodynamic performance of these configurations, coupled with the propulsion flow path, inherits the characteristics of their original airframe shapes, such as the high lift/drag ratio of sim-waverider and the low-drag performance of semi-axisymmetric cone configuration. The computed results also demonstrate that the inward-turning inlets integrate smoothly with their respective vehicle airframes and that the design method is viable.
- Published
- 2015
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