Browse Topic: Aerodynamics

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The Statistical Analysis of Commercial Flight Data for Defining the Payload-Range Performance of the Aircraft Conceptual Scheme Design2026-99-2311To be published on 10/30/2026
This research focuses on the application of statistical analysis of commercial flight data in aircraft conceptual scheme design. The payload-range performance of the commercial aircraft should be defined and analyzed by utilizing statistical methods during the conceptual scheme design, as it determines marketability. Statistical analysis is deemed essential due to the complexity and specific requirements of conceptual design. The research paradigm established in this study involves collecting and analyzing flight data of competitor aircrafts operating in the target market, using the OAG database as a foundation. This data is then utilized to build statistical models and conduct trade-off analysis. The results reveal that while the competitor aircraft has good route coverage, the conceptual scheme designed exhibits better payload-range performance, with a potential reduction in structural weight and better aerodynamic performance. Aircraft designers should take the imbalance in flight data between different airports, which is revealed by the application of statistical analysis, into consideration in conceptual scheme design. This study fills the gap between “market data-driven” and “performance modeling” in aircraft conceptual design, providing a reusable paradigm for subsequent research. The process of aircraft scheme design is a multi-disciplinary optimization process. When the range under certain payload of the concept scheme is already sufficient to cover the target market, how to conduct iterative design in conjunction with other indicators such as economy and commercial range is a problem worthy of in-depth study.
Gu, Xiangying, Cheng, Zhiyu
Machining Deformation Control of 5A06 Aluminum Alloy Aircraft Skin2026-99-2343To be published on 10/30/2026
Aircraft skin is a critical external structural component that provides aerodynamic profile, sustains and transfers aerodynamic loads, and protects internal systems from harsh environments. High machining precision is essential to ensure assembly accuracy and flight performance. However, large scale thin walled skin components are prone to significant machining deformation due to their low stiffness. Traditional deformation control methods, which relying heavily on experiments and full-process simulations, are inefficient and costly for industrial applications. To address this issue, this paper establishes a correlation model among machining parameters, residual stress, equivalent bending moment, and machining deformation. Single-factor experiments are conducted to reveal the effects of spindle speed, feed rate, and cutting depth on surface residual stress. Based on plate-shell theory, the relationship between residual stress and equivalent bending moment is established. The quantitative relationship between equivalent bending moment and machining deformation of the skin is obtained via finite element simulation modeling. Finally, a deformation control strategy for the skin during finish machining is established by optimizing the cutting depth. Experimental results show that after parameter optimization, the overall machining deformation of the 5A06 aluminum alloy skin is reduced by 81%, and the maximum deformation is controlled within 0.17 mm, which fully meets the aeronautical assembly requirements. This work provides an efficient and low-cost process optimization strategy for the machining deformation control of large weak-stiffness thin-walled components.
Chen, Shu-Guang, Wang, Jing-Kai, Wu, Chao, Wang, Tian-Rui, Yuan, Hao
Numerical Diagnosis and Evidence-Chain Analysis of the Non-Sustained Ignition Process in a Hydrogen/Air Turbulent Diffusion Flame under an LES–PaSR Framework2026-99-2324To be published on 10/30/2026
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Liu, Jiaqi, He, Jiandong, Yuan, Youquan, Duan, Yu
Comparative Numerical Study of Different Turbulence Modeling Approaches for Civil Aircraft Inlet Flows under Crosswind Conditions2026-99-2331To be published on 10/30/2026
This study constructs and validates a high-efficiency and high-fidelity adaptive Very Large Eddy Simulation (VLES) strategy based on user defined function(UDF) secondary development to investigate the complex and unsteady flow characteristics of civil aircraft intakes under crosswind conditions, conducting a comparative study of turbulence simulation methods across different hierarchies. Initially, the performance of traditional RANS turbulence models, including S-A, BSL k-ω, and SST k-ω, in simulating large-scale flow separation within intakes under crosswind conditions is evaluated, revealing that their applicability is limited. However, the predictive accuracy of RANS models can be improved to some extent by incorporating Explicit Algebraic Reynolds Stress Models (EARSM) and non-linear constitutive corrections. Under the maximum crosswind mass-flow condition, for complex flows dominated by shock and boundary-layer interaction, the SST model, high-resolution Large Eddy Simulation (LES), and the developed VLES model are compared. Furthermore, under variable crosswind mass-flow conditions, a comparative study on separation characteristics between the VLES and SST models is carried out. Finally, the simulation performance of the VLES model under installed nacelle conditions is verified. Research results indicate that the VLES model achieves superior near-wall boundary layer resolution while effectively mitigating the over-prediction of separation zone extent typically associated with LES, demonstrating higher accuracy without a significant increase in computational cost. Through verification via independent nacelle calculations, the VLES method shows a high degree of consistency with experimental data and non-linear SST model results in predicting separation characteristics under varying mass-flow rates, accurately reproducing the processes of shock-induced separation and boundary-layer reattachment. This research establishes the superiority of the VLES method in handling complex intake flow separation, laying a theoretical and technical foundation for its engineering application in the aerodynamic assessment of actual installed nacelles.
Jiang, Jintao, Han, Xingsi, Liu, Hao, Guo, Jin, Yu, Fan, Xu, Xiao
A Study on Gust Alleviation Based on Distributed Electric Propulsion2026-99-2304To be published on 10/30/2026
In a distributed electric-propulsion aircraft, multi-motor drive propellers distributed across the wings to provide the aircraft’s primary thrust. The electric control system enables rapid adjustment of propeller speed to control the overall attitude and flight path of the distributed electric propulsion aircraft. Furthermore, by utilizing the wake-induced acceleration effect generated by the propellers to alter the aerodynamic force distribution on the wing surfaces, it achieves gust attenuation. When encountering gusts, the PID control system adjusts the propeller slip to increase lift, thereby mitigating the effects of gusts on distributed electric propulsion aircraft. This paper employs PID control to regulate the steady-state performance of a distributed electric-propulsion aircraft under gusty conditions, with the objective of achieving the fastest return to a steady state. When encountering a headwind and a downdraft, the aircraft’s flight quality are severely disrupted; while airspeed, angle of attack, pitch angle, and rate of climb return to their original states or tend to stabilize, the effect of these forces causes the aircraft to lose height. After PID control is applied, under the influence of a tailwind disturbance, the aircraft’s descent under PID control is significantly less than under open-loop control, and it quickly returns to its original height and remains stable; Under the influence of downdraft turbulence, the aircraft under open-loop control is unable to return to its original height, whereas the aircraft under PID control drops slightly before returning to its original height.
Yang, Wenshuo, Yang, Youxu, Fu, Junquan, Shen, Junhui
A Comparative Study on Aerodynamic Characteristics and Stability of Twin-Boom UAVs with Typical Tail Configurations Under Propeller Slipstream Interference2026-99-2365To be published on 10/30/2026
The present study concentrates on aerodynamic behavior and static stability characteristics, and propeller slipstream interference of twin- boom unmanned aerial vehicles (UAVs) with three typical tail configurations. This study adopts a coupled VSPAERO approach, which incorporates a VLM-based solving technique and the Actuator Disk Model. Simulation results under the no-slipstream baseline condition reveal that the inverted V-tail layout delivers the highest aerodynamic efficiency. Its lift/drag ratio is considerably superior to those of the U-tail and inverted U-tail designs. While all configurations maintain good stability in longitudinal and directional axes, only the U- tail exhibits lateral static stability. When propeller slipstream is introduced, the lift-to-drag ratio of all layouts decreases noticeably, mainly due to strong local low-pressure regions that substantially increase pressure drag. In addition, the slipstream has little influence on longitudinal static stability, leaving pitching moment characteristics nearly unchanged. Nevertheless, the swirling flow generated by the propeller effectively improves lateral stability. It enhances the stabilizing effect of the U-tail, turns the lateral instability of the inverted U-tail into stable behavior, and reduces the lateral unstable characteristics of the inverted V-tail. In addition, the findings show that the sideslip angle β’s impact on the yawing moment is affected by the angle of attack α. Coupling between α and β, as well as propeller slipstream, should be considered in directional stability analysis. Increasing propeller diameter appropriately improves aerodynamic efficiency and directional static stability, while placing the propeller at or slightly forward of the baseline position minimizes adverse tail interference.
Wen, Jiayi
ARET-ALSTM: Intelligent Beam Prediction and Dynamic Compensation Network for Aerial Base Stations under Non-Stationary Turbulent Conditions2026-99-295410/19/2026
With the unprecedented surge in demand for flexible deployment and ultra-high throughput in next-generation wireless networks, airborne base stations (ABS), particularly unmanned aerial vehicles (UAVs), have become emerged as indispensable mobile communication infrastructure. To facilitate high-gain directional transmission within the millimeter-wave band, ABS frequently employ massive MIMO antenna arrays. However, under random disturbances caused by non-stationary turbulence, the system faces a severe physical bottleneck: weak anti-interference capability due to narrow beamwidth, which can easily lead to a sharp drop in link capacity. Addressing the two major shortcomings of existing deep learning prediction schemes—susceptibility to sensor noise interference and negative capacity performance shifts during stable periods, and response lag due to memory inertia during sudden turbulence periods—this paper proposes an ARET-ALSTM active compensation network based on SNR-aware multimodal attention, agile reset and adaptive event-triggered mechanisms. This network incorporates an event-triggered mechanism governed by a dynamic physical variance threshold, adaptively executing compensation during stable intervals to prevent excessive overshoot and redundant computational overhead. Simultaneously, it employs an agile feature reset mechanism based on an adaptive sliding window for concept drift detection, forcibly discarding old memories and reconstructing attention weights during sudden wind shear, achieving millisecond-level ultra-fast adaptation and directly driving network optimization with the goal of maximizing communication capacity. Simulation experiments show that, under different array configurations ranging from 2×2 to 16×16 and complex flow conditions, ARET-ALSTM successfully overcomes the physical capacity collapse limitation under large antenna scales, and its tracking agility and robustness are significantly better than benchmark algorithms such as Transformer, RNN and traditional Kalman filtering.
Tu, Jiajun, Zhou, Jihua, Li, Yanhang, Zhao, Tao, Huang, Hua, Wen, Yuanbin, Guo, Ziwen
Research on the Flow Characteristics of the Airflow Field in an Open Fan Array2026-99-297910/19/2026
Small aerial vehicles operating at low altitude are frequently exposed to wind fields with strong spatial gradients and rapid temporal variations. Although conventional closed-section wind tunnels provide well-controlled test conditions, they are generally unable to reproduce the large-scale non-uniformity typical of urban low-altitude environments. Open multi-fan arrays provide a promising alternative because they can generate programmable inflow conditions over a relatively large test area. In this study, a 9 × 9 open fan array is investigated using the momentum-source method to reproduce representative inflow conditions, including uniform flow and shear flow. The numerical results reveal a persistent edge-dissipation effect: velocity decays more rapidly and turbulent kinetic energy is higher near the outer fans than near the array center. In the uniform-flow case, a relatively stable low-turbulence corridor develops downstream of the array. In the shear-flow case, the imposed asymmetry is preserved, while edge-induced losses become more pronounced near the perimeter. These results clarify the main flow structures generated by open multi-fan arrays and provide a physical basis for future wind-environment testing of aerial vehicles.
Lu, Yuexuan, Tu, Zhan, Li, Daochun, Li, Huadong, Liu, Yiliang
Methodological Study on Fluid-Structure Interaction Dynamics of Spacecraft in Martian Rarefied Atmosphere Aerobraking2026-99-293210/19/2026
During aerobraking, spacecraft deploy large flexible solar arrays to obtain enough aerodynamic drag. In the rarefied Martian atmosphere, rapidly varying dynamic pressure causes low-frequency elastic vibrations of these appendages, leading to coupled translation-rotation-vibration fluid-structure interaction (FSI) that affects both aerodynamic characteristics and attitude stability. Traditional high precision methods such as DSMC are difficult to apply to long-duration simulations owing to their high computational cost. To solve this problem, this paper proposes a one-way FSI framework, which conbines a cross-regime panel method for aerodynamic calculation with a reduced-order multibody dynamic model. The simulation results show that the framework can reduce the computational burden while retaining the main physical characteristics required for the analysis. The aeroelastic response of a representative spacecraft configuration is analyzed, and the results can support configuration design, aerobraking corridor constraints, and control system development.
Zhou, Tianhao, Cui, Hutao
Switched Adaptive Flight Control of UAV Carrier Subject to Transient Separation Disturbances2026-99-295210/19/2026
A switched adaptive flight control architecture is proposed for fixed-wing carrier-sub UAVs to handle abrupt mass and inertia variations, as well as parameter uncertainties induced by transient aerodynamic interference, during sequential deployment. The separation process is rigorously modeled as a switched linear system, and a combined direct and indirect adaptive control scheme featuring an online Recursive Least Squares (RLS) modification is designed to compensate for model uncertainties. Furthermore, a dwell-time admissible switching law is established by solving Linear Matrix Inequalities (LMIs), ensuring the stability of the switching process through theoretically guaranteed Lyapunov energy drops at switching instants. Numerical simulations verify that transient tracking error spikes are significantly suppressed, and high-frequency oscillations are effectively attenuated compared to baseline controllers.
Chi, Haiyi, Yuan, Shuai
Closed-Loop Steam-Injected SOFC-GT Propulsion System with Thrust Compensation for High-Altitude Hydrogen UAVs2026-99-292710/19/2026
To address the requirements of high thermal efficiency and strict thermal control for high altitude long endurance unmanned aerial vehicles, as well as the problems of large additional water load and difficult high altitude condensation in traditional steam injected cycle aero engines, this paper proposes a closed loop steam injected cycle liquid hydrogen solid oxide fuel cell and gas turbine hybrid power system, which uses the cryogenic energy of liquid hydrogen fuel and external high altitude ram air to realize the condensation, collection and reuse of water vapor. This paper establishes a coupled thermodynamic and aerodynamic model, evaluates the benefits of the steam injected cycle at the design point, and analyzes the thermodynamic and aerodynamic characteristics of the system under off design conditions. The results show that the closed loop steam injected cycle effectively improves the work capacity of the turbine and the power generation efficiency of the system. At the design point, the rated net output power and power generation efficiency of the system reach one thousand two hundred and fifteen point zero kilowatts and sixty-six point two eight percent respectively. In addition, the system recovers kinetic energy by using the Meredith effect, which greatly offsets the aerodynamic drag caused by the introduction of ram air. Even when the flight speed exceeds Mach number zero point six four, the system can completely offset the aerodynamic drag and even generate additional thrust. Power margin analysis proves that the system still has sufficient power reserve to complete the flight mission under cruise conditions. This study provides a theoretical basis for the power and thermal control design of high altitude long endurance hydrogen powered unmanned aerial vehicles.
Kang, Qiming, Shen, Yiling, Li, Chengjie, Qin, Jiang, Ji, Yongbin, Jiang, Junwen
Aerospace & Defense Technology: Oct 202626AERP1010/8/2026
Terabit Optical Communications in Space: Engineering High-Speed Networks for Data Centers in Orbit Mild Hybrids: A Current-Gen Bridge to Electrifying Military Ground Vehicles The Integrated and Flexible Approach to Large-Scale Metrology: How Integrating Laser Trackers and Modular Arms Creates a 'Unified Nervous System' The Defense Industry Continues to Meet CMMC Phase II Requirements Despite 60-Day Pause In Space, No One Can Hear You Stream AMD to Bring UCIe Connectivity to Select Versal Adaptive SoCs How Special Interface Gages Provide Microscopic Precision for Designing Ballistic Missiles The pristine precision needed to certify the nation's underwater nuclear deterrent is anchored on the talents of civilian scientists at a Navy laboratory in Southern California. Rapidly Testing Deployable Systems Sandia National Laboratories is evaluating portable security architectures that combine radar, drones, ground sensors, cameras and wireless communications networks into a single rapidly deployable system for remote and austere environments. Testing focuses on sensor integration, resilient communications and edge-based data processing to improve situational awareness while operating within real-world bandwidth constraints. Tailored Surface Vibrations to Improve Aerodynamic Performance in Passenger Jets University of Colorado Boulder researchers have demonstrated two new phononic flow-control concepts, super-resonance and scatterless interference, that use engineered subsurface vibrations to interact with boundary-layer airflow across a broader range of turbulence frequencies than previously possible. By delaying flow instabilities without altering a wing's external shape, the technology could reduce aerodynamic drag and improve fuel efficiency in passenger aircraft. New Type of Attack Can Slip Past the Defenses in Your Computer's Processor MIT researchers found a way to exploit a split-second gap in chip security - and used it to acquire a Linux system's password file. Army Tests Safer Electrical Connectors for Ground Vehicle Readiness U.S. Army DEVCOM Ground Vehicle Systems Center engineers are evaluating cadmium- and hexavalent chromium-free electrical connectors designed to reduce hazardous material exposure while maintaining corrosion protection, electrical performance, and long-term vehicle sustainment.
Structural Robustness and Regime-Dependent Uncertainty in a Reduced-Order Physics Model for Vehicle Fuel Consumption Using Monte Carlo Analysis2026-24-00159/21/2026
Accurate prediction of vehicle fuel consumption typically relies either on simplified empirical correlations or on high-fidelity simulations that are computationally expensive. However, the structural robustness of reduced-order physics-based models under parametric uncertainty has not been systematically quantified. In particular, the interaction between model simplifications and uncertainty in vehicle and fuel properties across different operating regimes remains insufficiently investigated. This study presents a reduced-order physics-based framework derived from fundamental force and energy balances to estimate fuel consumption in L/100 km. The model includes aerodynamic drag, rolling resistance, inertial effects, drivetrain efficiency, and fuel lower heating value. Unlike purely empirical formulations, the proposed structure preserves physical interpretability while remaining computationally efficient. Monte Carlo simulations are employed to propagate simultaneous uncertainties in vehicle mass, drag coefficient, rolling resistance, engine efficiency, and fuel energy content. Thousands of randomized realizations are executed to quantify output variability, compute confidence intervals, and evaluate robustness indices. In addition, regime-dependent dominance transitions are analyzed by comparing urban and highway operating conditions. Results show that parameter influence is strongly dependent on speed regime: mass and rolling resistance dominate in low-speed conditions, while aerodynamic parameters become dominant at high speeds. Fuel energy content and efficiency exhibit nearly linear inverse relationships with consumption. The reduced-order structure demonstrates stable variance behavior under realistic uncertainty ranges, supporting its suitability for parametric studies and alternative fuel assessment. The proposed framework contributes a systematic evaluation of structural robustness in simplified physics-based fuel consumption models and provides a scalable methodology for uncertainty-aware automotive performance analysis.
Gutierrez, Marcos, Taco, Diana
Further Investigation of Brake Squeal: Effect of (Inboard/Outboard) Pads Property Differential2026-01-07999/14/2026
It was reported earlier that the wear differential between the inboard pad and the outboard pad leads to brake squeal generation. The (inboard/outboard) pads wear differential can occur due to hardware issues such as brake pad drag and/or two different wear rates of the (I/O) pads, which is caused by two different material properties of the pads although the pad formula may be the same. It is found that (I/O) pads compressibility differential/hardness differential/friction differential are all interrelated and that they contribute to brake squeal generation in addition to the inboard pad tangential/radial taper wear. A method has been found to separate the inboard pad friction and the outboard pad friction and to estimate each friction coefficient.
Liu, Richard, Wu, Shane, Wu, Godot, Zou, Tianlang
Aerodynamic Disc Brake Drag: An Elusive Source of Variability2026-01-08029/14/2026
The ever-present drive to increase vehicle range and efficiency has resulted in disc brake caliper requirements at or near zero residual drag. It is increasingly critical to understand and design around potential edge cases that can drastically increase off-brake drag. One frequently observed, but often misunderstood, phenomenon is drag induced by aerodynamic forces surrounding the brake pad. Complex airflow characteristics surrounding the pad in the brake corner environment can lead to Venturi Effect induced air pressure differentials on each side of the pad, leading to transient, yet pronounced, increases in brake drag. This paper will follow a case study during which brake pad pressure differentials were discovered and objectively measured, review the Venturi Effect as it relates to brake corners, and explore modelling approaches for identifying and correcting designs that are prone to this phenomenon.
Robere, Matthew, Tresmondi, Thales
Design Considerations for Optimizing the Wheel Bearing Outer Ring Bolt-Mounting Pattern for Reduced Drag2026-01-08309/14/2026
Electric vehicles (EVs) impose more demanding operating conditions on wheel bearing systems due to increased vehicle mass, higher drive torque, and the need to maximize energy efficiency and driving range. These factors elevate the loads transmitted through the bearing to knuckle joint and often require higher clamp loads to ensure joint integrity. However, higher clamp loads amplify distortion of the wheel bearing outer ring, increasing rotational drag and reducing bearing durability. Controlling outer ring distortion is therefore critical for EV wheel bearing design, as well as for high performance vehicles that experience severe lateral loads at the hub to knuckle interface. This paper investigates key design considerations for optimizing the wheel bearing outer ring and its mounting interface to minimize distortion under elevated clamp loads. A comprehensive CAE-based Design of Experiments (DOE) is used to evaluate the influence of multiple bolt-mounting patterns including rectangular, square, and trapezoidal configurations and the relative alignment of the bolt pattern between the outer ring and knuckle. The study also compares the performance of M12 and M14 fastener variants across loading conditions representative of EV and high-performance applications. The results identify geometric and interface design parameters that significantly reduce outer ring out of roundness, thereby lowering drag torque and improving long-term bearing life.
Mandhadi, Chaitanya Reddy, Lee, Seungpyo, Bovee, Benjamin, Callaghan, Kevin
Aerodynamic Design and Optimization Study of a Ma 0-5 Two-Dimensional Wide-Range Adjustable Nozzle2026-99-14039/11/2026
To address the thrust requirements across multiple operating conditions of hypersonic vehicles during wide-speed-range flight (Ma 0–5), this paper presents the design of a two-dimensional adjustable nozzle with a circular-to-rectangular cross-section. A maximum-thrust contour was constructed using the method of characteristics, and the aerodynamic performance and structural features of this rotation-based adjustment approach were systematically analyzed. The results demonstrate that the nozzle achieves a thrust coefficient between 0.951 and 0.992 across the entire flight envelope, with a thrust vector angle consistently maintained at 0°, indicating excellent thrust performance and flow-field symmetry. Furthermore, by introducing a biaxial transition segment and optimizing its tangent angle (θ = 130°) alongside fillet rounding (R = 30 mm), unsteady flow oscillations and separation at high Mach numbers were effectively eliminated, enhancing both structural durability and aerodynamic stability.
Feng, Fan, Lv, Zheng, Xu, Jinglei
Aerodynamic Load Calculation and Prediction Method for Folded Wing Mechanism2026-99-12899/4/2026
The folding wing mechanism is widely used in aircraft design. Whether the folding wing surface can unfold smoothly determines whether the aircraft can fly normally. Therefore, studying the aerodynamic loads and structural deformations during the unfolding process of folded wing surfaces is very important. The motion process of a folded wing mechanism is a typical fluid-structure interaction (FSI) process. During deployment, the wing surface moves under the combined action of the actuator’s pull and the aerodynamic loads from the incoming flow, while the large deformation of the wing surface during its movement, in turn, affects the aerodynamic loads on the mechanism from the flow field. Considering the FSI effects during the unfolded motion process of the folded wing, simulation was conducted using the ALE algorithm in LS-DYNA to obtain the kinematic and dynamic parameters in the unfolded motion process, and also to get the aerodynamic torque on the wing under different angles and angular velocities. In practical engineering applications, the actuation force of the deployment mechanism can vary due to factors such as the amount and performance of the pyrotechnic material. Consequently, the final velocity and the whole motion process of the wing mechanism will also change. For the calculation of aerodynamic external loads under multiple operating conditions, using the ALE algorithm will consume a large amount of computational time and cost. Given the high computational cost and long computation time of finite element simulations, a BP neural network was established to calculate the aerodynamic loads on the wing surface under different actuation forces. This allows for a rapid assessment of whether significant deformation or damage will occur to the folding mechanism or nearby components during the deployment process.
Wei, Ting, Li, Naitian, Tong, Zongkai
CFD-Based Aerodynamic Stability Analysis of a Quadrotor UAV2026-99-12539/4/2026
This study analyzes the aerodynamic stability of a typical quadrotor UAV during hover and vertical flight using Computational Fluid Dynamics (CFD). A fitted relationship between single propeller rotational speed versus lift and torque was obtained through simulation. Rotor speed input parameters were determined by combining this relationship with force analysis under ideal conditions. Lift and torque variation data for each rotor under two typical flight conditions were subsequently acquired. The research examines changes in lift and torque caused by aerodynamic interference between rotors, which induces UAV instability. To address the additional rotor lift from airframe obstruction of airflow, a “Reduction Value Method” is proposed to correct the lift data. Kinematic simulations conducted in Adams show significant displacement and angular displacement fluctuations in both hover and vertical flight states. Instability is more pronounced during vertical motion. This research provides a theoretical basis for understanding UAV flight stability mechanisms and optimizing control strategies.
Zhao, Haiyuan, Li, Jia, Song, Jiafeng
Research on Scalelike Adaptive Suction Flow for Wide-Speed Range Hypersonic Inlets2026-99-12529/4/2026
As critical components of aircraft, hypersonic inlets utilize shock wave compression effects to pressurize incoming flow. The interaction between shock waves and the boundary layer tends to generate separation zones, and it adversely affects inlet performance. As a method to significantly enhance inlet performance, suction technology can substantially reduce the size of separation zones when they form in the inlet. However, when the inlet is started and operating normally, suction configurations may cause mainstream leakage and make it difficult to meet the requirements of inlets with wider speed ranges. This paper designs an adaptive scaliform suction structure that utilizes a lift-generating design to induce a slight upward deflection of high-speed near-wall flow. It can reduce high-speed mainstream leakage without compromising the effectiveness in low-speed separation zones. Numerical simulations are employed to evaluate its suction performance in both inlet separation zone flow fields and supersonic mainstream flow fields. The internal flow mechanisms of the scaliform suction structure are investigated, and differences in its behavior across various suction flow fields, as well as its interference with the mainstream, are discussed. The study reveals that when the height of the scaliform suction structure is approximately 1/8 of the incoming flow’s velocity boundary layer height, the suction flow coefficient in the separation zone is twice that in the hypersonic mainstream. Furthermore, the loss in Mach number and total pressure recovery coefficient of the near-wall supersonic mainstream is controlled within 5%. This structure exhibits an adaptive suction capability for separation zones, thereby extending the starting speed range of the inlet.
Zhao, Xuening, Zhao, Yilong
Scaling Behavior of Levitation and Dragging Force in Electrodynamic Suspension Systems2026-99-12109/4/2026
The geometrical and velocity scaling behavior of levitation and dragging forces in Electrodynamic suspension (EDS) systems was studied by both analytical and numerical methods, to provide comparisons between designs for both on-board and ground-mounted magnetic components. Effects of system dimension, levitation gap, magnetic field dependence of critical current density, and vehicle velocity were studied. The lift-to-self-weight ratio of two realistic EDS systems and their geometrical scaling were studied numerically.
Shao, Nan, Zhang, Chang, Shang, Liang, Yu, Wenjing
Dynamic Modeling and Robust Active Control of Graphene-Piezoelectric Composite Missile Wings with Elastic Boundary Constraints2026-99-12819/4/2026
To improve the stability and vibration suppression capability of missile wings under complex aerodynamic conditions, this study develops a dynamic model and explores the active control strategy for a graphene-reinforced piezoelectric composite missile wing subjected to elastic boundary constraints. An electromechanically coupled dynamic model with elastic boundary conditions is constructed by employing CLPT, the geometric nonlinearity following the von Karman assumptions, and piezoelectric coupling theory. The system is discretized and solved numerically using characteristic orthogonal polynomials and the Galerkin method. The influences of graphene distribution configurations, material properties, and boundary flexibility on the linear natural frequencies and nonlinear hardening characteristics are investigated. Results show that the X-type graphene distribution significantly enhances the equivalent stiffness and reduces nonlinearity. Boundary flexibility markedly modulates the vibration characteristics; in particular, increased structural flexibility strengthens geometric nonlinearity, leading to noticeable changes in frequency characteristics and hardening degree. A robust state-feedback controller together with a full-order observer is developed using the Linear Matrix Inequality (LMI) framework, and their performance is verified under different parameter disturbances and uncertainties. The control strategy effectively suppresses vibrations while maintaining good robustness, with the best performance achieved under X-type graphene reinforcement combined with thin piezoelectric layers. This study reveals the coupling mechanisms among material distribution, boundary flexibility, and robust control, providing a theoretical basis for the structural optimization and active control design of smart missile wings.
Qin, Shilong, Chen, Jie
Numerical Analysis of the Frequency Acceleration Effect on the Aerodynamic Efficiency of 3-DoFs Flapping Wing2026-99-12889/4/2026
This study examines how frequency acceleration affects the aerodynamic efficiency of a forward flying airfoil by establishing a kinematic model and conducting numerical simulations using the NACA0012 model. Since the aerodynamic force coefficients have been obtained in previous studies, this paper directly utilizes these coefficients to evaluate the effects of different frequency acceleration combinations on aerodynamic efficiency. It is concluded that under the condition of no pitch frequency acceleration, the combination of positive plunging frequency acceleration and sweep frequency acceleration significantly reduces the lift efficiency from 89.7% (under no frequency acceleration) to 18.1%, and can increase the propulsion efficiency from 44.1% (under no frequency acceleration) to 75.5%. Furthermore, under the AM-8 condition, the lift efficiency shows a decreasing trend as the acceleration factor increases. The analysis and investigation of frequency acceleration effect provide a theoretical foundation for enhancing the aerodynamic performance and optimizing the structural design of flapping wing drones.
Kong, Fanwei, Qu, Ligang, Li, Zhandong, Li, Jing, Lao, Yile
Research and Practice of Emergency Rescue Unmanned Patrol Flying Equipment2026-99-03378/14/2026
To enhance China’s disaster and accident emergency response capabilities and strengthen the digital battlefield system for emergency rescue, an integrated multi-payload unmanned aerial surveillance and communication support system has been developed for extreme weather conditions and ‘triple-disconnection’ disaster scenarios. This paper sets out to address the limitations of traditional emergency drones, including poor environmental adaptability, weak payload capacity, and operational inconvenience. The system’s resistance to wind and rain has been significantly enhanced through the optimization of its airframe design. The innovative design incorporates dual-station symmetric conjugate antennas with planar blind-spot coverage systems, integrating public and self-organizing network base stations to achieve three-dimensional signal coverage and heterogeneous network integration. This enhances ground cellular network resilience. Multi-functional reconnaissance payloads are integrated and compatible with day/night and smoke/rain scenarios, thus overcoming the limitations of single-source visual information perception. The system employs zero-length deployment and parachute recovery methods, thereby facilitating rapid deployment and terrain-independent take-off and landing capabilities. The simulation results obtained demonstrate excellent aerodynamic performance, thus permitting safe operation in wind conditions up to Force 8. The antenna system under discussion is innovative in nature and has been developed to achieve 360° three-dimensional signal coverage. The primary function of this system is to ensure sustained communication link integrity. The field trials further corroborate the aircraft’s stable low-altitude cruising capability in Force 8 winds, thereby averting congestion in constrained rescue airspace. The dual-base station design, incorporating symmetric conjugate antennas and blind-spot compensation antennas, has been demonstrated to reliably restore public ground network signals within a 6.7-kilometre radius. The development of this unmanned aerial patrol system addresses a significant gap in low-altitude rescue capabilities for intelligent unmanned equipment in harsh environments. It underpins the integrated emergency command and operations system for intelligence, command, and execution, as well as the integrated emergency communication support system spanning the air, land, and sea domains. This advancement has been demonstrated to enhance disaster response efficiency and auxiliary decision-making effectiveness under extreme conditions.
Bian, Lu, Fang, Yudong, Yang, Jixing, Zhang, Chen, Hu, Bin, Zhang, Mingyue
Numerical Study on Measurement Accuracy of Liquid Level/Capacity Measurement Device and System in a Shipboard Environment2026-99-01227/31/2026
In the marine environment, navigation safety and operational effectiveness depend heavily on the precision of liquid level/capacity measurement equipment and systems. In order to examine their measurement accuracy under complex operational situations, including ship navigation states and water tank sloshing, this study employed computational fluid dynamics (CFD) methodologies. The numerical technique performs a thorough examination of how various operating conditions impact measurement accuracy and integrates the volume of fluid (VOF) model and laminar flow model with appropriately defined boundary conditions and solver settings. The findings indicate that constant-speed navigation has minimal impact on accuracy, horizontal acceleration causes moderate deviations, and accelerated diving greatly reduces precision. The amplitude of water tank sloshing has a positive correlation with measurement error. When sloshing amplitudes are less than 1 m, the integration of the resulting acceleration efficiently lowers deviations while preserving excellent accuracy. In light of these results, we advise adding accelerometers to differential pressure transmitters to improve measurement precision. This investigation provides data-driven references and technical solutions for system design and operational standard formulation in marine measurement systems.
Shang, Jin, Qin, Ziming, Wang, Yingwei, Wu, Chao, Zhao, Fenggang, Chen, Liang, Xia, Wei, Yan, Jin, Chen, Min, Chen, Guoao
Optimization of Pneumatic Conveying Elbows to Reduce Grain Particle Normal Contact Forces via CFD-DEM Coupling Method2026-99-01167/31/2026
This study presents a refined design for pneumatic conveying pipelines, featuring a grooved structure at the bend aimed at reducing particle breakage during transportation. Using soybean particles as a focus, the research employs a gas-solid two-phase flow approach to explore how different groove depths and widths influence the breakage rate. We used CFD-DEM simulation techniques, combining fluid mechanics with discrete element modeling to achieve a more accurate representation of particle motion and collision forces during expressing. Based on these simulations, we identified the most effective combination of groove width and spacing. Experimental results showed that a groove width of 4.5 mm coupled with a 40 mm spacing could decrease impact forces on particles by approximately 5% to 10% at expressing speeds of 15 m/s and 20 m/s. Throughout all measured time intervals, the impact forces remained stable, with turbulence exerting minimal influence on the particle forces.
Luo, Xinhao, Yang, Tiancheng, Huang, Bo, Mao, Genwu, Dong, Deliang, Shi, Heng, Li, Xiaoliang, He, Bo
Characterization of Dynamic Characteristics of Pneumatic Systems Based on Aerodynamic Frequency Ratio2026-99-02307/31/2026
To address the ambiguity in the relationship between design parameters and energy characteristics in pneumatic systems caused by gas compressibility and low viscosity, which leads to design redundancy, this paper proposes a dynamic characteristic characterisation method based on the pneumatic frequency ratio. This aims to establish a correlation mechanism between system energy consumption and dynamic performance. By constructing a nonlinear dynamic model of a double-acting cylinder, the dimensionless aerodynamic frequency ratio (Ω) is defined to characterise the matching relationship between the system’s natural and operating frequencies. Analytical relationships between Ω and key design parameters—such as cylinder diameter and valve sound velocity conductance—are derived, thereby establishing a normalised similarity criterion. Through combined simulation analysis and experimental validation, the regulatory patterns of Ω on the dynamic characteristics of displacement, velocity, and pressure are systematically investigated. Results indicate that under consistent Ω conditions, the normalised dynamic characteristic error across aerodynamic systems with varying parameters can be controlled within 4%. A significant linear correlation exists between the frequency ratio and the amplitude of cylinder chamber pressure differentials, with errors below 3%. The study further reveals that Ω exerts a nonlinear regulatory effect on system responsiveness and stability: increasing Ω enhances dynamic response speed but exacerbates pressure fluctuations, whereas decreasing Ω slows response but improves pressure stability. This methodology provides a theoretical foundation for energy-efficient design, parameter matching, and intelligent control of pneumatic systems, effectively addressing a gap in existing research on energy-dynamics coupling analysis.
Li, Mengru, Du, Hongwang, Wang, Jiajia, Yuan, Tingting, Xiong, Wei
Angular Vibration Model of Frictional plates in High Speed Open Wet clutch2026-99-02347/31/2026
High-speed wet clutches may experience dynamic instability between the friction plates, leading to rattling vibrations and a significant increase in drag torque. This study employs a homogeneous flow model to characterize the gas-liquid two-phase flow within a high-speed clutch. It establishes a dynamic model for the angular oscillation of friction plates. Finite-element numerical simulations and stability analyses were conducted. The results indicate that as the clutch speed difference increases, the density and viscosity of the two-phase flow decrease rapidly, leading to a sharp reduction in fluid stiffness and damping. Consequently, the friction plates become more susceptible to angular oscillation. The stability of angular oscillation is determined by two key parameters: dimensionless comprehensive stiffness and critical frequency ratio. Higher dimensionless comprehensive stiffness and a lower critical frequency ratio enhance oscillation stability. Numerical evaluations of various groove types reveal that as rotational speed and friction plate clearance increase, the fluid stiffness coefficient, damping coefficient, dimensionless comprehensive stiffness, and critical moment of inertia all decrease, thereby reducing angular oscillation stability. Among the tested groove geometries, enclosed grooves and spiral grooves exhibit superior stability due to their strong hydrodynamic effects, yielding the highest dimensionless comprehensive stiffness. The critical frequency ratio for the self-excited angular oscillation of friction plates is approximately 0.5, termed the half-frequency oscillation characteristic. Experimental data validate the proposed angular oscillation model and its frequency response, providing a theoretical foundation for performance prediction and stability optimization in high-speed clutch design.
Cheng, Xu, Peng, Zengxiong, Zhang, Jing, Jin, Jiayin
Study on Energy-related Mechanisms of Aeroelastic Instability of Ultra-Long Flexible Wind Turbine Blades Under Various Working Conditions2026-99-01347/31/2026
With the continuous increase in wind turbine power capacity, ultra-long flexible blades face intensified aeroelastic instability risks due to reduced structural stiffness, enhanced modal coupling, and aerodynamic nonlinearity. In addition to the analysis of basic vibration characteristics, this study focuses on energy-related mechanisms of aeroelastic instability under various working conditions. Using a numerical model integrating Dynamic Blade Element Momentum Theory (DBEMT) and Geometrically Exact Beam Theory (GEBT), over 400 time-domain simulations were conducted to characterize instability onset and development. Results reveal four distinct aeroelastic instability regions, each dominated by specific modes. In Region A, flutter dominated by the 2nd flapwise mode is observed. In Region B, flutter dominated by the 1st edgewise mode is observed. In Region C, flutter dominated by the 2nd edgewise mode is observed. While in Region D, where the medial angle of attack (AoA) of the blade has exceeded the stall angle, stall-induced vibration dominated by the 1st flapwise mode is observed. Energy analysis shows aerodynamic work concentration near the blade tip drives instability, with diverse energy exchange patterns across regions. Except for some operating conditions in region C, where instability is dominated by edgewise energy absorption, most aeroelastic instability conditions are dominated by flapwise energy absorption. Torsional degree of freedom contributes minimally to aerodynamic work, but the torsional vibration exerts a notable influence on the AoA. This, in turn, changes the comprehensive aerodynamic forces impacting the blade as well as the general aeroelastic stability. This study clarifies the relationship between operating conditions and energy-driven instability, offering some reference values for the design work and safety assurance of ultra-long flexible blades of the wind turbine.
Wang, Su, Chen, Jiajia, Zhou, Le, Shen, Xin, Li, Chun, Du, Zhaohui
Influence of Aero Enablers on Brake Cooling Performance2026-36-03177/30/2026
Amid growing society concerns about environmental sustainability, fuel consumption has become a key factor in mitigating greenhouse gas emissions. As a result, modern vehicle design increasingly prioritizes aerodynamic drag reduction. However, aerodynamic enhancements can significantly affect brake cooling, since airflow distribution plays a crucial role in braking performance. This study explores the interplay between underbody aerodynamic features and brake cooling efficiency in production vehicles. Three body styles—compact sedan, midsize SUV, and minivan—were evaluated to determine how varying aerodynamic configurations influence airflow around the wheel assemblies. The findings highlight critical trade-offs between aerodynamic optimization and thermal management, offering valuable insights for achieving balanced vehicle development strategies.
Batista, Lorena, Motta, Daniel, Seren, Ericson, Bergel, André, Sarmento, Alisson, Terra, Rafael
A Standardized Mid-Fidelity Aerodynamic Comparison of Four Tiltrotor eVTOL Configurations Using SUAVE and VSPAero2026-99-08397/30/2026
This study compares 4 representative tiltrotor platforms: Joby S4, Archer Midnight, Vertical Aerospace VX4, and Uber eCRM-001 in a typical UAM mission profile under standardized rotor and wing assumptions using an integrated OpenVSP-SUAVE-VSPAero framework. This work aims to isolate the influence of eVTOL configuration from proprietary optimizations on thrust generation and aerodynamic interaction by using standard wing airfoils and a consistent rotor design tool. Vehicle geometries were modeled in OpenVSP. Rotor Operating conditions were obtained from the SUAVE conceptual design platform. Mid-fidelity aerodynamic analysis was done using VSPAero. SUAVE results show a decrease in thrust requirements as the tilt angle decreases, with the most complexity occurring in the transition phase where lift shifts from rotors to wing. Archer Midnight and Vertical Aerospace VX4 show higher hover thrust requirements due to their high takeoff weights. They display localized thrust increase near mid transition due to numerical adjustments made to achieve solver convergence. Joby S4 and Uber eCRM-001 display a smoother thrust requirement trend. VSPAero simulations also show a gradual decrease in thrust from hover to cruise. Joby S4’s continuously active rotor configuration maintained more stable performance than the hybrid configurations, which deactivate lift-only rotors after takeoff. A comparative flight feasibility analysis was conducted, defined as the difference between VSPAero-predicted thrust and SUAVE-required thrust. This analysis reveals that Joby S4 maintains a positive margin across most flight phases. Archer Midnight and Vertical Aerospace VX4 show a marginal deficit in near-cruise phases. Uber eCRM-001 showed negative margins throughout the mission, indicating limited aerodynamic robustness under standardized assumptions. Rotor-wing interactions enhances rotor thrust across all mission segments, while creating periodic pressure oscillations on the wings. Rotor-rotor interactions provide limited near-field benefits that dissipate in forward flight. The findings of this study highlight the significance of eVTOL configuration in determining performance and aerodynamic efficiency.
Sawron, Md Sadat Shahrier
Systematic Assessment of State-of-the-Art Approaches Available for Variable Camber Morphing01-19-01-00057/29/2026
Aerodynamicists around the globe are developing mechanisms and structures inspired by nature that enable variable camber morphing (VCM) for aerodynamic surfaces. The implementation of the VCM mechanism in an airplane wing enhances the performance and stability during various flight segments. The present review article is focused mainly on the up-to-date VCM methods in a qualitative as well as quantitative approach that are specific to Aircraft/unmanned aerial vehicle (UAV) wing configurations. Initial literature discussions are confined to the conventional mechanisms that enable VCM in different aircraft configurations and the added aerodynamic advantages such as lift enhancement, drag reduction, boundary layer separation, and flow control. However, those designs need either external shape optimization or internal structural refinements to ensure the factor of safety (FoS). The modern aviation industry is also focused on bioinspired technology because of the adaptive flying capabilities and stall-delay characteristics. Therefore, a review of bioinspired VCM methods that are assessed based on the aerodynamic potentials is sequentially organized in the article. Additionally, considerations are motivated by the application of various compliant structural patterns for VCM in the aircraft industry. The discussion indicates the prospective benefits of morphing toward the future of the Green Aviation industry.
Manjunath, S. V., Jini Raj, R.
Optimization Design and Performance Verification Method of Antiaircraft Gun Fuze2026-99-16307/24/2026
In order to ensure that the high-caliber artillery ammunition fuses can successfully complete their combat tasks with high quality, it is necessary to optimize the design of their structure and conduct simulation verification of their performance. Through optimization design, this paper determined that the distance between the antenna plate and the wind cap of the proximity detonation module of the high-caliber artillery ammunition fuse is 6.2mm, and the thickness of the wind cap top is 12.9mm; it also determined that in the coaxial line feeding mode, a circular patch is used as the antenna shape, with the lowest return loss (reaching -38.5244 dB), which is conducive to the emission of electromagnetic wave energy; by introducing the methods and processes of intensity simulation analysis and aerodynamic thermal simulation analysis, as well as the methods of performance verification, this paper provides reference and guidance for the simulation analysis of similar systems.
Liu, Liwen, Sun, Zhangyi, Ning, Quanli, Cai, Canwei
Numerical Study of Structures for a Next-Generation Supersonic Transport2026-99-16267/24/2026
Because of the increasing requirement for frequent international traveling, developing a new generation of supersonic transport is critical for commercial aviation. The typical features of supersonic transport are a large swept-back wing and thin airfoil, potentially causing excessive tip deflection and triggering aeroelastic divergence. Hence, conducting evaluation, analysis, and optimization of the structures of an SST is essential. This study applied the finite element method to investigate the wing and fuselage structures under aerodynamic loads during cruise for a next-generation supersonic transport aircraft. Deformations and stress contributions were analyzed, showing the feasibility of the structure design and the stress concentration zones requiring reinforcement in the detailed design. Structural optimizations were also conducted, yielding significant weight reduction.
Ding, Menglong, Xu, Zhaoyang, Wang, Yongqiang, Meng, Li, Tan, Jiaxin, Xuan, Jinting, Bie, Dawei, Shao, Lintao
Parameter Identification of Projectiles Based on an Improved Butterfly Algorithm Optimizing a Mixed Kernel Extreme Learning Machine2026-99-16167/24/2026
Accurate projectile dynamic modelling requires identifying aerodynamic parameters. The traditional methods for identifying aerodynamic parameters of missiles suffer from significant modeling errors. Therefore, this study proposes an improved butterfly-shaped optimization hybrid extreme learning machine algorithm. It combines the butterfly algorithm with a hybrid extreme learning machine, Cauchy mutation, and adaptive weight. The search ability of the Butterfly algorithm is enhanced by introducing the Cauchy distribution function and adaptive weighting factors. In addition, to balance the weights of searches and to optimize the regularization coefficients and kernel function parameters, the dynamic switching probability p is introduced. The identification accuracy of four different algorithms was compared under noise-free conditions. The feasibility of the improved butterfly-optimized hybrid extreme learning machine was verified. When there is noise, the strength of the algorithm is confirmed by comparing the effect of different noise levels on how well it can identify things. The simulation results show that the improved butterfly optimization hybrid extreme learning machine algorithm has higher accuracy and better robustness in identifying projectile aerodynamic parameters. The simulation results show that the improved butterfly optimization hybrid extreme learning machine algorithm has higher accuracy and better robustness in identifying projectile aerodynamic parameters.
Wang, Qianqian, Wang, Kangjian, Jiao, Wenjie, Yi, Wenjun, Chen, Jintong
Study on the Aerodynamic Characteristics of Canard Configuration Missile Influenced by Aileron2026-99-16107/24/2026
The canard configuration has been widely adopted in short-range missiles. However, its main drawbacks include difficulties in roll control and a limited angle-of-attack (AoA) range. Compared to conventional canard missiles, the addition of a pair of control surfaces (referred to as “aileron”) behind the canard control surfaces achieves decoupling between the roll channel and pitch-yaw channel. To investigate the influence of ailerons on the aerodynamic characteristics of canard configuration missiles, numerical simulations were conducted for two typical flow conditions: subsonic (Mach 0.5) and supersonic (Mach2.0). The results show that the introduction of ailerons increases the normal force of missiles, causes the center of pressure to shift forward, and reduces the static stability of missiles, thus enhancing their maneuverability. When the ailerons control the roll channel, the effectiveness of the rolling moment remains consistent over the entire AoA range without adverse effects. However, when the canards control the pitch channel, the interference caused by the deflection of the canards on the ailerons leads to increased lift and generates additional nose-up pitching moments, which reduces the pitching moment effectiveness of the missile.
Zhang, Zilun, Xu, Jiasheng, Mei, Zhiwei
Biomimetic Design and Numerical Analysis of a VIV Suppression Fairing for Offshore Risers2026-99-16407/24/2026
As oil and gas exploitation advances into deep seas, risers linking offshore platforms and subsea extraction systems endure long-term complex marine loads. Fatigue damage from Vortex-Induced Vibration (VIV) has become a key factor limiting the safe operation of deep-sea engineering structures. To address this issue, a bionic adaptive rotating fairing, which is adjustable to ocean current directions, was designed. Its main components include buoyancy blocks, a fairing with spiral guide rails on the inner wall, and clamps, which work together to reduce VIV by regulating flow patterns. Numerical simulations of concave and convex fairings showed that under subcritical flow, shifting from a concave to convex cross-section gradually enhances the fairing’s drag and lift reduction effects on risers, with a steady improvement trend. Further comparisons were made between 0.25D convex fairings, 0.35D convex fairings, and bare risers, focusing on drag/lift reduction, vortex shedding frequency, and Strouhal number. Both convex fairings exhibited similar VIV suppression performance to the bare riser, but differed significantly in the percentage reduction of vortex shedding frequency and Strouhal number. Thus, the 0.25D convex fairing was identified as the optimal configuration for VIV suppression among the concave-convex fairings studied.
Zhang, Xu, Song, Guangming, Wang, Baozhong, Zhao, Jinpeng, Chen, Qianshuo
Load Analysis of Flap and Slat Actuators in Aircraft High-Lift Systems2026-99-18027/17/2026
This study develops an end-to-end load analysis scheme for flap and slat actuators, which comprise the aircraft’s high-lift system, and the analysis results are directly integrated into hardware optimization. Because they shoulder heavy responsibilities during the takeoff and landing phases, whether they can remain rock-solid under complex aerodynamic conditions or even remain unmoved in emergencies is directly related to their overall safety performance. This work process is closely linked and includes three major links. First of all, according to the CCAR-25.301 standard, the load envelope under normal working conditions is sorted out, and the limit cases of abnormal faults are exhausted. Subsequently, ANSYS Workbench pulled silk and peeled off the cocoons to capture the peak stress at the engagement between the output shaft and the gear. In the end, the closed-loop verification of the customized test bench made the theoretical calculations and the hardware-measured data exactly the same. The entire package provides designers with hardcore data support, and always uses airworthiness, not convenience, as the criterion when improving actuator performance.
Xu, Yuanze
Flight Test Analysis Method for Aerodynamic Characteristics of Helicopter Rotor in Level Flight2026-99-18217/17/2026
To analyze flight test failures, ensure flight safety, and provide data support for the aerodynamic design of helicopters, it is necessary to conduct aerodynamic characteristic analysis of helicopter rotors based on flight test data. This article establishes a helicopter rotor aerodynamic model and an aerodynamic parameter identification method in level flight. In this article, we take the flight test data of a helicopter’s level flight performance as an example, and use the genetic algorithm and Particle Swarm Optimization for parameter identification calculation. We obtain aerodynamic parameters such as rotor angle of attack and rotor lift-to-drag ratio in the helicopter’s level flight state, and so on, and analyze the aerodynamic characteristics of the helicopter’s rotor. The results show that the method established in this paper can accurately and effectively obtain the aerodynamic parameters of the helicopter rotor through flight tests. It can also evaluate the aerodynamic characteristics of the helicopter rotor and meet the requirements of the American standard ADS40 for obtaining the aerodynamic characteristics of the helicopter through flight tests. Thus, it has great engineering application value.
Zhao, Jingchao
The Impact of Powerplant on Stall Characteristics of Propeller Aircraft2026-99-18377/17/2026
This study focuses on a compact-layout propeller aircraft, investigating how its powerplant influences stall characteristics via combined theoretical analysis of aerodynamic principles and validation with flight test data. Special attention is paid to the effects of propeller slipstream, appropriate evaluation criteria are selected to assess the aircraft’s high-angle-of-attack performance and stall behavior, and the Weissman chart criteria are further adopted to analyze its lateral-directional departure tendencies. A theoretical analysis of the stall characteristics of compact-layout propeller aircraft is conducted. Through flight test data analysis, the stall characteristics of compact-layout propeller aircraft are studied, with an emphasis on understanding how slipstream effects influence their longitudinal and lateral-directional stall characteristics.
Fang, Shengyou, Yang, Xiaoli, Jiang, Tianjun, Fu, Yi
Ground Vehicle-Mounted Testing of UAV Aerodynamic Forces2026-99-18187/17/2026
The rapid advancement of Unmanned Aerial Vehicles (UAVs) has imposed increasingly demanding requirements on aerodynamic force testing. Ground vehicle-mounted testing provides a safe, relatively accurate, and cost-effective experimental method for testing UAV aerodynamic forces. This paper focuses on a ducted fan as the research object and presents a ground vehicle-mounted testing system designed to investigate its aerodynamic characteristics. The testing process includes building a testing platform, ground static testing, vehicle-mounted testing, and systematic data analysis. Comparative results between experimental tests and Computational Fluid Dynamics (CFD) simulations demonstrate that the vehicle-mounted testing method can accurately provide the aerodynamic force of the ducted fan, with errors in aerodynamic force and moment measurements being less than 5%. This approach could provide important technical support for the design and optimization of ducted UAVs.
Mao, Sen, Zhao, Chuangxin, Wu, Shuang, Feng, Yupeng, Zhang, Yanwu, Chen, Lin
Numerical Simulation Study on the Transformation Process of Multiple Droplets into Liquid Films2026-99-18337/17/2026
The numerical simulation of the transformation process of multiple droplets into liquid films is a complex problem involving multiphase flow, interface dynamics, and heat and mass transfer. It usually requires the combination of fluid mechanics, interface science, and numerical calculation methods. Based on the smooth particle fluid dynamics method, this paper establishes a multiphase fluid-solid coupling interaction model among droplets, surrounding air and solid walls, and studies the dynamic change process of multiple raindrops dispersed in different grooves. The results show that when the contact Angle is small, the boundaries of multiple raindrops do not come into contact. The multiple raindrops evolve in their respective grooves and eventually form multiple raindrops that approach the steady-state contact Angle. The second situation is that the boundaries of multiple raindrops do not come into contact, the raindrops start to fuse, and multiple raindrops form a larger one. At this point, the contact point of the gas-solid-liquid phase disappears, that is, the "regulating force" of the contact Angle is 0. This paper provides important numerical simulation references for flight safety, aerodynamic performance and anti-icing/de-icing technologies during the flight of aviation aircraft.
Huo, Ye, Chen, Yongheng, Sun, Cunxiang
A New Spike-Dual-Disk-Channel Concept with Openings on the Aerodisk2026-99-18417/17/2026
To reduce the drag and intense heating faced by the hypersonic vehicle during flight, a novel spike–dual-disk–channel configuration is proposed, featuring a slotted channel at the head and exhaust at the second aerodisk. Numerical simulations were conducted using Fluent at 30 km and 5 Ma in free-flow. The new configuration's comprehensive aerodynamic performance were evaluated and compared to those of the single-disk and dual-disk configurations. The simulation results indicate that the new configuration exhibits superior comprehensive aerodynamic performance compared to the single-disk configuration. In contrast to the dual-disk configuration, the new configuration slightly compromises drag reduction (by approximately 1%), but achieves significantly better thermal protection (by approximately 10%).
Luo, Shenxing, Fang, Shuzhou, Ye, Chen
Dynamic Characteristics Study of the Deployment Process of Aircraft Folding Wing2026-99-18607/17/2026
Folding wing mechanisms are widely applied in aircraft structural design. This design reduces the size of the aircraft, making it easier to store and transport. Whether the foldable wing can successfully deploy determines the completion of the flight mission. Therefore, it is crucial to study the kinematic and dynamic parameters of the mechanism during the deployment process. The deployment of the folding wing typically occurs within milliseconds. The flow field imposes aerodynamic loads on the mechanism, causing it to move, while the large deformation motion of the mechanism, in turn, affects the aerodynamic loads from the flow field. This is a typical fluid-structure interaction (FSI) process. Traditional CFD methods for solving the deployment process in a decoupled manner often result in large errors and cumbersome procedures. To investigate the aerodynamic loads and deformation of the folding wing mechanism during deployment, the ALE algorithm in LS-DYNA was selected to directly solve the kinematic and dynamic parameters of the mechanism in unsteady flow fields, guiding the design of foldable wing mechanisms.
Wei, Ting, Tong, Zongkai, Li, Naitian
Research and Analysis on Convergence in Hypersonic Slip Flow Numerical Simulation2026-99-18057/17/2026
With CFD technology, a numerical simulation method based on the Navier-Stokes (NS) equations with slip boundary conditions was established. For the flow conditions at altitudes of 60 km and 70 km with a Mach number of 20, the calculation convergence problem of slip flow was analyzed through a flat plate. The research shows that as the altitude increases, the degree of rarefaction increases, and the frictional drag decreases. Without slip, the viscous drag decreases from 17.8 N at an altitude of 60 km to 9.97 N at 70 km. With a slip, it decreases from 17.5 N to 9.63 N. After adding the slip condition, the calculation convergence is slower compared with that of the non-slip attached flow. The difference between the calculation results with and without slip increases as the altitude increases. During the iteration process, the difference between the cases with and without slip gradually decreases. The difference in viscous force between the cases with and without slip is 1.76% at 60 km and reaches 3.47% at 70 km.
Hu, Junlin, Wang, Yaping, Gao, Yunguang, Wan, Lv, Pan, Sha
Aerodynamic Optimization Method Based on a Hierarchical Adaptive Activation Function Neural Network2026-99-18237/17/2026
Efficient optimization of aerodynamic shapes is a critical challenge in aircraft design. Traditional CFD-based optimization workflows suffer from high computational costs and low efficiency, which severely restricts their practical engineering application. In this paper, a novel aerodynamic optimization method based on a hierarchical neural network with adaptive activation functions is proposed. The network adopts learnable B-spline activation functions and is hierarchically constructed in accordance with the sharing status of B-spline control points. After being trained to achieve fast and accurate prediction of aerodynamic performance, the network can effectively replace the traditional CFD module in the optimization loop. The primary advantage of the proposed method is that it significantly reduces the computational cost during the optimization process while ensuring that the prediction accuracy is not compromised. This work thereby presents a novel strategy and technical framework for streamlining the design process of hypersonic vehicles.
Liu, Di, Wang, Yongfeng, Wen, Hong, Wei, Yuanhang, Ma, Hengwei, Zhao, Runhui
Attitude Control of a Variant Flying Wing UAV Based on L1 Adaptive and Fuzzy Clustering2026-99-18587/17/2026
This study presents a full-envelope attitude-stabilisation and trajectory-tracking strategy for morphing flying-wing UAVs operating in highly nonlinear and strongly coupled conditions. The approach integrates fuzzy C-means (FCM) envelope partitioning with L1 adaptive control. Small-disturbance linear models are first generated at multiple altitude–Mach trim points; the FCM algorithm then performs unsupervised clustering in the state space, yielding representative subintervals that capture local flight-dynamic characteristics. The optimal cluster number and fuzziness exponent are selected using the partition coefficient, partition index, partition entropy, and Xie–Beni indices. For each sub-interval, an LQR baseline controller is designed and augmented by an L1 adaptive compensator, where a low-pass filter decouples adaptation from robustness to guarantee specified transient-performance bounds under matched/unmatched uncertainties, actuator saturation, and external disturbances. A feed-forward pre-filter realises online decoupling of the multi-input multi-output channels, thereby enhancing adaptability to variable sweep angles and large aerodynamic variations. Simulations covering low-speed/small-sweep and high-speed/large-sweep scenarios demonstrate that the proposed method sustains robust stability across the clustered envelope, outperforming conventional control schemes and confirming its engineering applicability.
Tang, Longhao, Sun, Xiaoxu, Liu, Changlin
Guidance Law Design and Simulation Verification for Multi-Missile Cooperative Attack of UAVs2026-99-18137/17/2026
With the increasing demand for multi-unmanned aerial vehicle (UAV) cooperative operations, the design of guidance laws with time and angle synchronization constraints has become a critical technology to enhance strike precision. This paper focuses on a UAV-launched multi-missile cooperative attack scenario, proposing a composite guidance law that integrates the advantages of existing optimal time/angle control guidance laws. By introducing a time error feedback term and an angle constraint term, combined with an adaptive disturbance observer to compensate for aerodynamic errors and target maneuvers, the proposed guidance law ensures a terminal miss distance of less than 0.5 m while achieving a time error ≤0.6 s and an incidence angle deviation ≤2° among multiple missiles. Simulation and test results both demonstrate that the four-missile cooperative attack achieves time dispersion within 1s, satisfying engineering practicality and anti-interference requirements.
Xie, Lijun, Wang, Deshuang, Yang, Xiaodong, Zhang, Tingting, Li, Yang
Numerical Investigation of Inverted Airfoils in Ground Effect for Motorsport Applications01-19-01-00047/15/2026
Ground effect plays a critical role in enhancing the aerodynamic performance of race cars by increasing downforce without a proportional rise in drag. Despite its importance, the influence of airfoil geometry on inverted airfoils operating in ground proximity remains underexplored in open literature. This study addresses this gap through a detailed numerical investigation of chord-dominated ground effect using two-dimensional Reynolds-Averaged Navier–Stokes (RANS) simulations. A range of NACA four-digit airfoils is systematically analyzed to isolate the effects of camber, thickness, and camber location on aerodynamic performance in ground proximity. Results show that increased camber enhances downforce and efficiency both in and out of ground effect; thinner airfoils yield higher downforce and efficiency in ground effect; and forward camber locations outperform rearward ones in maximizing downforce contrary to out-of-ground-effect trends. Detailed pressure distribution and flow separation analyses explain the underlying mechanisms, offering actionable guidelines for optimizing ground effect airfoil design in motorsport.
Chowdhury, Rohan, Shukla, Dhwanil
Guidelines for Aerodynamic Assessment of Medium and Heavy Commercial Ground Vehicles Using Computational Fluid DynamicsJ2966_202607 (Current)7/14/2026
This document outlines general requirements for the use of CFD methods for aerodynamic simulation of medium and heavy commercial ground vehicles weighing more than 10000 pounds. The document provides guidance for aerodynamic simulation with CFD methods to support current vehicle characterization, vehicle development, vehicle concept development, and vehicle component development. The guidelines presented in the document are related to Navier-Stokes and Lattice-Boltzmann based solvers. This document is only valid for the classes of CFD methods and applications mentioned. Other classes of methods and applications may or may not be appropriate to simulate the aerodynamics of medium and heavy commercial ground vehicle weighing more than 10000 pounds.
Truck and Bus Aerodynamics and Fuel Economy Committee
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