Article
Mechanics
Yakang Kong, Yun Wu, Haohua Zong, Shanguang Guo
Summary: This paper presents an experimental study on supersonic cavity flow control using a spanwise pulsed spark discharge array (SP-PSDA), focusing on its control effect and underlying mechanism. Results show that the SP-PSDA induces thermal bulbs, causing wave-like oscillation in the shear layer. The study finds that SP-PSDA actuation at 5 kHz has a better control effect and enhances the whole hairpin structure's I Rms. Proper orthogonal decomposition reveals the coupling of thermal bulbs with the shear layer to form large-scale coherent structures that excite the Kelvin-Helmholtz instability.
Article
Multidisciplinary Sciences
Seyyed Amirreza Abdollahi, Moharram Jafari, Saman Aminian, M. Fattahi, P. D. Uyen
Summary: In this study, the impacts of upstream shock waves on fuel mixing in a scramjet engine are investigated using computational fluid dynamics (CFD) simulations. The results demonstrate that the usage of upstream shock waves significantly increases fuel penetration and enhances the vortex region downstream of the jet.
SCIENTIFIC REPORTS
(2023)
Article
Mechanics
Xiaoling Shi, Dunlan Song, Hui Tian, As'ad Alizadeh, Masood Ashraf Ali, Mahmoud Shamsborhan
Summary: Comprehensive computational investigations have been conducted to examine the role of an annular air jet on fuel mixing in the combustion chamber. The results show that the injection of the annular jet can enhance circulations and improve fuel mixing inside the chamber.
Article
Engineering, Aerospace
Dai Jian, Zuo Qiuru, Huang Chao
Summary: The study found that the grooved configuration significantly improves supersonic mixing in the scramjet combustor, enhancing fuel uniformity in the downstream region.
Article
Engineering, Aerospace
A. A. Dhankarghare, T. Jayachandran, T. M. Muruganandam
Summary: This study combines a strut and a cavity into a strut cavity and compares it with a wall cavity using numerical simulations at different Mach numbers and aspect ratios. The results show that the wall cavity is more prone to oscillations compared to the strut cavity. The generation process of waves inside the cavity is revisited, where both the unstable shear layer and vortex shedding contribute to the wave generation in supersonic flows.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Physical
Fuzhang Wang, Hasan Sh. Majdi, Hayder A. Dhahad, Taher A. Nofal, Awad Musa
Summary: This paper investigates the effect of an upstream oblique ramp on the fuel mixing process of hydrogen multi-jets in supersonic cross airflow. The results show that the presence of the oblique ramp significantly enhances fuel mixing, and the productivity of the divergent ramp is higher than that of the convergent ramp.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Physics, Fluids & Plasmas
Hariswaran Sitaraman, Nicholas Brunhart-Lupo, Marc Henry de Frahan, Shashank Yellapantula, Bruce Perry, Jon Rood, Ray Grout, Marc Day, Roba Binyahib, Kenny Gruchalla
Summary: This paper is associated with a video winner of a 2020 American Physical Society's Division of Fluid Dynamics Gallery of Fluid Motion Award for work presented at the DFD Gallery of Fluid Motion. The original video can be viewed online at the Gallery of Fluid Motion website.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Engineering, Aerospace
Zhongliang Shen, Shuaixian Yu, Shichuang Zheng, Taher A. Nofal, Awad Musa, Z. Li
Summary: This study investigates the impact of an upstream inclined ramp on the fuel mixing mechanism of multi-jet configurations in supersonic crossflow. The results show that the ramp has a more significant effect on the circulation factor and mixing performance in the low jet space.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Aerospace
Yu Jiang, R. Moradi, Abdullah M. Abusorrah, Mohammed Reza Hajizadeh, Zhixiong Li
Summary: This study investigates the mixing and distribution of multiple hydrogen jets under the influence of a downstream sinusoidal wall, revealing that the frequency of the downstream wavy wall significantly limits fuel distribution and that increasing jet spacing on the symmetry plane decreases fuel concentration. Computational fluid dynamics with SST turbulence model is used to simulate sonic multi hydrogen cross jets at supersonic air stream, highlighting the importance of downstream wavy profiles on fuel distribution and mixing region.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Aerospace
Esteban Cisneros-Garibay, Carlos Pantano, Jonathan B. Freund
Summary: This article analyzes simulations of both inert mixing and sustained combustion for a cavity flameholder based on corresponding experiments. The simulations accurately reproduce the experimental results and analyze the effects of cavity combustion on core-flow gas dynamics and cavity entrainment.
Article
Engineering, Aerospace
Jieli Wei, Jian An, Qi Zhang, Hua Zhou, Zhuyin Ren
Summary: Understanding the coupling effect of fuel injection and cavity on flow characteristics is crucial for hydrogen supersonic flame stabilization and optimization. This study uses the active subspace (AS) method to quantitatively reveal the intrinsic connections between flow and flame stabilization. A flame stabilization metric is proposed for AS analysis and multiobjective optimizations. The results show that key performance metrics exhibit one-dimensional active subspaces. Fuel injection pressure, cavity length-to-depth ratio, and cavity depth are leading factors in governing total pressure loss.
Article
Thermodynamics
Z. Li, Jiaxuan Leng, Nidal H. Abu-Hamdeh, Khaled O. Daqrouq, Awad Musa, Osama K. Nusier
Summary: The effects of lateral injection from the circular strut on the fuel mixing and distributions in a scramjet engine for high-speed flight are comprehensively investigated using computational fluid dynamics (CFD). The results show that the circulation factor is reduced and the mixing performance is improved when the single cross jet is replaced by the lateral injection system or when the strut height of lateral injection is increased. Furthermore, replacing the single normal injection with a lateral nozzle located on a circular strut significantly improves the mixing performance behind the injector.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Engineering, Aerospace
Tao Tang, Guoyan Zhao, Hongbo Wang, Mingbo Sun, Zhenguo Wang
Summary: In this paper, the authors numerically study the cavity parameters to investigate the factors and mechanism of flame flashback. The results are validated and compared to previous experiments. It is found that the changes in cavity parameters affect the mixing of fuel wake and jet penetration depth. Additionally, factors such as shear layer, acoustic oscillation, and nitrogen throttling induce boundary layer separation. Under favorable conditions, thermal choking is formed and drives the reverse propagation of the high-temperature flame.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING
(2023)
Article
Multidisciplinary Sciences
Seyyed Amirreza Abdollahi, Ghazal Rajabikhorasani, As'ad Alizadeh
Summary: The efficient injection system plays a crucial role in the implementation of air breathing propulsion systems at supersonic flow. This research investigates the use of extruded multi-injectors in fuel distribution and mixing through the combustor. By visualizing the role of vortices formed near the injectors, it is found that extruded nozzles significantly enhance fuel jet diffusion in the scramjet's combustor.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Physical
S. Jeyakumar, Jayaraman Kandasamy, Mehmet Karaca, K. Karthik, R. Sivakumar
Summary: The study investigates the performance of modified strut injection strategies in a supersonic scramjet combustor, demonstrating that dual injection configuration can reduce shock wave impact and maintain the magnitude of internal forces and total pressure loss. Multiple injections alter the frequency and number of dominant modes in the flow field.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Engineering, Aerospace
J. Hollom, N. Qin
Summary: The study uses uncertainty in the critical amplification factor N-cr to assess surface and flow quality of natural laminar flow airfoils. Uncertainty in various aerodynamic coefficients is quantified to evaluate airfoil performance, and robust shape optimization is conducted to improve performance and reduce standard deviation. The trade-off between mean performance and standard deviation is observed, with sensitivity to uncertainty in N-cr impacting flow characteristics.
AERONAUTICAL JOURNAL
(2021)
Article
Computer Science, Interdisciplinary Applications
Guglielmo Vivarelli, Ning Qin, Shahrokh Shahpar, David Radford
Summary: In this article, a novel combination of feature and adjoint-based mesh adaptation methods is investigated and applied to typical three-dimensional turbomachinery cases. The proposed process improves the global flow solution by employing feature-based mesh movement, and then tunes the mesh for each quantity of interest using adjoint refinement. Comparison with a process utilizing only the adjoint refinement procedure shows significant benefits in terms of accuracy of performance quantity.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS
(2021)
Article
Computer Science, Interdisciplinary Applications
Guglielmo Vivarelli, Ning Qin, Shahrokh Shahpar, David Radford
Summary: This paper discusses the effectiveness of an anisotropic sensor based on functional volume-mesh sensitivity quantities in improving CFD simulations. By automatically modifying grids and relocating nodes to problematic regions, the reliability of the model is enhanced.
COMPUTERS & FLUIDS
(2021)
Article
Engineering, Aerospace
Feng Deng, Ning Qin
Summary: In this study, a new hybrid multi-objective EI method is proposed for expensive aerodynamic shape optimization problems, aiming to improve algorithm efficiency and robustness by enhancing the infill criterion. Experimental results show that the proposed method outperforms traditional algorithms and standard optimization algorithms in handling complex design spaces, demonstrating higher efficiency and robustness.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING
(2022)
Article
Engineering, Aerospace
Feng Deng, Cheng Xue, Ning Qin
Summary: A novel shape parameterization method for airfoil design is proposed, which provides design variables related to aerodynamic characteristics based on linearized aerodynamic theory. The method offers more useful aerodynamic performance parameters.
Article
Mechanics
Feng Xie, Jose D. Perez-Munoz, Ning Qin, Pierre Ricco
Summary: A turbulent drag-reduction method utilizing synthetic jet sheets was investigated through direct numerical simulations. By adjusting the angle and height of the jet sheets, a drag reduction of 10% to 30% was achieved. The study also found that the global skin-friction drag reduction was a result of a finite counter flow induced by the interaction between the jet-sheet flow and the main flow.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Engineering, Mechanical
Luka Vincekovic, Alistair John, Ning Qin, Shahrokh Shahpar
Summary: This work presents the aerodynamic topology optimization of high-pressure turbine rotor blade tips. Before carrying out the topology optimization on the blade tip, some initial tip design studies were conducted. A winglet tip was optimized first, resulting in a 1.40% increase in aerodynamic efficiency compared to the datum design. Then, a radial basis function-based parametrization was used to create a single squealer rim on the datum blade's tip that could move in the circumferential direction, resulting in a 0.46% increase in efficiency. Afterwards, a combination of winglet and topology free squealer tips was investigated via topology optimization, resulting in better designs compared to the flat tip winglet. However, gradient-based methods struggled to reach an optimum solution due to the flexibility of the design space, which was resolved by optimizing the most promising design subspace.
JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Aerospace
Feng Deng, Haifeng Wang, Cheng Xue, Ning Qin
Summary: This paper presents a combined experimental and numerical investigation on the aerodynamic load reduction using steady blowing on the suction surface of a swept wing. The study reveals that upstream blowing causes a larger reduction in lift and bending moment compared to normal blowing. It is also found that the aerodynamic load reduction increases with the increase in jet momentum. The linear jet velocity distribution with the lowest blowing velocity at the outer end of the jet region achieves the maximum load reduction. Three key flow mechanisms related to load reduction are identified.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Review
Chemistry, Multidisciplinary
Yonghong Li, Ning Qin
Summary: The importance of gust load control and reducing aircraft weight is highlighted in this article. Both conventional and non-conventional techniques for gust load alleviation are reviewed, with a focus on the research progress and performance of fluidic actuators for flow control. The results show that fluidic actuators demonstrate fast response characteristics and are capable of adaptive gust load control.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Aerospace
Cheng Xue, Feng Deng, Haifeng Wang, Ning Qin
Summary: Microjets arranged on the wing surfaces of civil transport aircraft can effectively reduce aerodynamic load on a supercritical airfoil. By solving the Reynolds-averaged Navier-Stokes (RANS) equations, the study simulates subsonic and transonic flowfields around the airfoil with various angled microjets. The results demonstrate that shifting the blowing direction downstream to upstream increases lift reduction and power efficiency.
INTERNATIONAL JOURNAL OF AEROSPACE ENGINEERING
(2023)
Article
Engineering, Aerospace
Feng Deng, Shenghua Zhang, Ning Qin
Summary: In this paper, a closed-loop control using an active shock control bump (SCB) has been proposed to suppress the buffet on a supercritical airfoil flying at transonic speeds. The control law is designed based on the lift coefficient as the feedback signal and the bump height as the control variable. Numerical simulations show that the buffet can be effectively suppressed by optimizing the control law parameters, namely the gain and the delay time. The active SCB has advantages over the reference active trailing edge flap, including less sensitivity to control law parameters and a shorter response time.
Article
Engineering, Aerospace
Siqiang Deng, Yibin Wang, Ning Qin
Summary: This article presents a method for automatically generating feature-aligned anisotropic structured meshes, which is capable of providing high resolution for complex two-dimensional flow features. The method involves extracting dominant flow features and geometric entities, and generating high-quality meshes that are suitable for shock capturing and higher-order reconstruction.
Article
Thermodynamics
Cleopatra Cuciumita, Ning Qin, Shahrokh Shahpar
Summary: This study proposes a novel optimization process to maximize the aerodynamic efficiency of a modern fan blade while satisfying the structural constraint imposed by material limits. The method utilizes the discrete adjoint for evaluating the aerodynamic efficiency sensitivity and a response surface method for the structural stress constraint. A fast, meshless method is used for stress calculations to handle the large number of required sampling points in the response surface generation. The method is applied to the optimization of a practical fan blade, demonstrating an efficiency improvement of 0.6% while keeping the stress below a prescribed value of 500 MPa assuming a titanium alloy material. Without the stress constraint, the efficiency benefit is higher at 0.9%, but the maximum stress exceeds the material's acceptable criterion at almost 1000 MPa. The modular nature of the method allows for adaptation to various turbomachinery blade designs. Flutter analysis of the optimized fan blade has also been conducted due to its practical significance.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART A-JOURNAL OF POWER AND ENERGY
(2023)
Article
Engineering, Aerospace
Zhaolin Chen, Xiaohui Wei, Tianhang Xiao, Ning Qin
Summary: A 2-D airfoil shape optimization in the transonic low-Reynolds number regime is conducted. The results show that the unconventional airfoil has a significant drag reduction at high Mach numbers and the maximum lift-to-drag ratio is influenced by the Mach number. In contrast, the conventional airfoil experiences an increase in lift fluctuation with an increase in Mach number.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING
(2023)
Article
Engineering, Aerospace
Shenghua Zhang, Feng Deng, Ning Qin
Summary: This paper investigates the effects of buffet caused by the interaction between shock waves and boundary layers on aircraft during transonic flight conditions. It proposes the application of shock control bumps to enhance the robustness of the closed-loop buffet control system. The results indicate that coupling the shock control bumps greatly enhances the closed-loop flap control and improves the aircraft's aerodynamic performance.
