Browse Topic: Aerodynamics

Items (8,394)

Structural Robustness and Regime-Dependent Uncertainty in a Reduced-Order Physics Model for Vehicle Fuel Consumption Using Monte Carlo Analysis

2026-24-0015

9/21/2026

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 Differential

2026-01-0799

9/14/2026

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 Variability

2026-01-0802

9/14/2026

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 Drag

2026-01-0830

9/14/2026

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 Nozzle

2026-99-1403

9/11/2026

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

Scaling Behavior of Levitation and Dragging Force in Electrodynamic Suspension Systems

2026-99-1210

9/4/2026

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

Aerodynamic Load Calculation and Prediction Method for Folded Wing Mechanism

2026-99-1289

9/4/2026

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

Research on Scalelike Adaptive Suction Flow for Wide-Speed Range Hypersonic Inlets

2026-99-1252

9/4/2026

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

CFD-Based Aerodynamic Stability Analysis of a Quadrotor UAV

2026-99-1253

9/4/2026

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

Dynamic Modeling and Robust Active Control of Graphene-Piezoelectric Composite Missile Wings with Elastic Boundary Constraints

2026-99-1281

9/4/2026

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 Wing

2026-99-1288

9/4/2026

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 Equipment

2026-99-0337

8/14/2026

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

Optimization of Pneumatic Conveying Elbows to Reduce Grain Particle Normal Contact Forces via CFD-DEM Coupling Method

2026-99-0116

7/31/2026

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

Numerical Study on Measurement Accuracy of Liquid Level/Capacity Measurement Device and System in a Shipboard Environment

2026-99-0122

7/31/2026

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

Characterization of Dynamic Characteristics of Pneumatic Systems Based on Aerodynamic Frequency Ratio

2026-99-0230

7/31/2026

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

Study on Energy-related Mechanisms of Aeroelastic Instability of Ultra-Long Flexible Wind Turbine Blades Under Various Working Conditions

2026-99-0134

7/31/2026

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

Angular Vibration Model of Frictional plates in High Speed Open Wet clutch

2026-99-0234

7/31/2026

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

Influence of Aero Enablers on Brake Cooling Performance

2026-36-0317

7/30/2026

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 VSPAero

2026-99-0839

7/30/2026

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 Morphing

01-19-01-0005

7/29/2026

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 Fuze

2026-99-1630

7/24/2026

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 Transport

2026-99-1626

7/24/2026

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 Machine

2026-99-1616

7/24/2026

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 Aileron

2026-99-1610

7/24/2026

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 Risers

2026-99-1640

7/24/2026

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 Systems

2026-99-1802

7/17/2026

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

Research and Analysis on Convergence in Hypersonic Slip Flow Numerical Simulation

2026-99-1805

7/17/2026

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 Network

2026-99-1823

7/17/2026

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

Numerical Simulation Study on the Transformation Process of Multiple Droplets into Liquid Films

2026-99-1833

7/17/2026

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

Flight Test Analysis Method for Aerodynamic Characteristics of Helicopter Rotor in Level Flight

2026-99-1821

7/17/2026

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

Ground Vehicle-Mounted Testing of UAV Aerodynamic Forces

2026-99-1818

7/17/2026

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

A New Spike-Dual-Disk-Channel Concept with Openings on the Aerodisk

2026-99-1841

7/17/2026

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

The Impact of Powerplant on Stall Characteristics of Propeller Aircraft

2026-99-1837

7/17/2026

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

Attitude Control of a Variant Flying Wing UAV Based on L1 Adaptive and Fuzzy Clustering

2026-99-1858

7/17/2026

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

Dynamic Characteristics Study of the Deployment Process of Aircraft Folding Wing

2026-99-1860

7/17/2026

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

Guidance Law Design and Simulation Verification for Multi-Missile Cooperative Attack of UAVs

2026-99-1813

7/17/2026

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 Applications

01-19-01-0004

7/15/2026

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 Dynamics

J2966_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

Study on the Effect of Flap Parameters on Hydrodynamic Characteristics of Marine Flap Rudder

2026-99-0526

7/10/2026

By tweaking the flap’s deflection angle, the flap rudder significantly enhances the hydrodynamic performance. This study investigates the influence of the location of the flap rotation axis and the size of the flap’s deflection affect how well the rudder performs in the water, using computer simulations to obtain high-resolution flow-field data. The results demonstrate that the flap rudder consistently generates more lift than your standard rudder. Prior to stall, pushing the flap rotation axis further back results in less lift, but also less drag. For maximum lift at small or moderate angles of attack, a rotation axis located at 0.75 c provides the highest lift coefficient, whereas the 0.85 c configuration combined with δ = 25° offers the best compromise between postponed stall and maintained lift-to-drag ratio. Put the pivot at 85% chord and set the flap deflection to 25 degrees, and an optimal configuration is achieved in terms of lift and drag. The configuration yields a stall angle pushed out to 16 degrees and a maximum lift coefficient that jumps to 3.86. That’s a significant increase of 15.77 % over what you’d get with 15° flap deflection. Ultimately, this research lays the groundwork for designing better flap rudders and gives us some serious pointers on how to increase the performance of ship rudders in the real world.

Liu, Zirong, Wang, Jianming

Data Fusion Techniques for Optimizing Motorsport Aeromap Generation: A Survey

2026-01-5058

7/7/2026

This paper reviews data fusion strategies for generating aerodynamic databases and evaluates their suitability for motorsport aeromaps, with emphasis on the operational constraints specific to Formula One. A structured survey and classification of the state of the art is presented, grouping approaches into (i) surrogate-agnostic methods, (ii) kriging-based methods, and (iii) neural network–based methods. In addition, the survey explores advanced techniques currently underutilized in aerodynamic database applications but that show promise. These methodologies are discussed in the context of addressing limitations inherent in traditional approaches, such as dependency on nested sampling plans and linear correlation assumptions between low- and high-fidelity datasets. The review indicates that, although multi-fidelity data fusion is well established in aerospace aerodynamic database generation, its direct translation to motorsport requires additional considerations. In the Formula One context, the most plausible deployment may involve fusing legacy and current datasets, rather than combining low- and high-fidelity evaluations of the same geometry. This shift in premise could increase exposure to negative transfer and therefore necessitate additional methods to minimize it. This study provides one of the first motorsport-focused reviews and syntheses of data fusion methods for aerodynamic database generation. It is intended to guide motorsport engineers and researchers toward more efficient and effective aeromap generation strategies. Collectively, the findings establish a foundation for subsequent phases of a broader project to minimize the number of data points required to generate an aeromap, with the present survey constituting the first part of that effort.

Ongley, Thomas James Henry, Teschner, Tom-Robin, Ashton, Neil, Siampis, Efstathios

From Wind Tunnels to an AI-Supported Data-Driven Development Ecosystem

2026-01-0767

7/1/2026

Despite advances in CFD, wind tunnel testing remains indispensable for aerodynamic validation, correlation, and homologation. Increasing configuration complexity, shortened development cycles, and stringent result robustness and documentation requirements demand a shift from isolated facilities to integrated, data-driven ecosystems within the overall development and company-wide test processes. We present a software-centric approach integrating wind tunnel operations into a strategic element of the Digital Thread. By orchestrating test planning, execution, data acquisition, and documentation within a unified framework, experimental data becomes reusable across projects and traceable for compliance and homologation. The interaction between CFD and physical testing is important. Such approach systematically improves simulation models with wind tunnel tests. And CFD results guide efficient test matrix definition. Extended measurement methodologies include automated actuation of active aerodynamic components in test sequences, while BEVs introduce further aerodynamic and thermal aspects for range and efficiency. Thus, extended and automated test definition down to the step-level of test sequences is introduced. Within such integrated environment, AI can be a supporting engineering tool to enhance testing. AI-based methods can assist in identifying relevant test points within complex parameter spaces and in correlating experimental and simulated results, assisting but not replacing established engineering judgment. Also, for the operating department, analyzing process data for maintenance predictions and efficiency optimizations can be assisted by AI-based methods and supporting AI-agents. The approach boosts efficiency by reducing test effort and tedious manual tasks, leading to shorter development cycles, supporting improved time-to-market. Structured workflows and standardized data handling enhance data quality, improve comparability of results, and ensure robust documentation for reliable audit trails. By combining physical testing, simulation, and intelligent processing, the wind tunnel becomes a reproducible, innovation-enabling element in modern product development, positioning software as the backbone of efficient, future-proof aerodynamic testing.

Jacob, Jan D.

Effect of Static Fin on the Stability and Aerothermodynamic Characteristics of the Re-entry Vehicle

01-19-01-0003

6/11/2026

Investigating high-speed aerodynamics and aerothermodynamics presents a significant challenge for manned re-entry missions. The thermal effects on the surface of the re-entry vehicle and atmospheric stresses are primarily influenced by re-entry type and flight trajectory. This study investigates the monostability characteristics and aerothermodynamics of the Orion re-entry vehicle by incorporating static fins onto the aft fuselage of the vehicle, ensuring the lift-to-drag ratio remains unaffected throughout the numerical simulations. The study evaluated two different Mach numbers of 7 and 9 at various altitudes. The models were analyzed at different angles of attack from 0° to 90° in increments of 15°. The model with static fins exhibits a displacement in the monostable trim point, a reduction in the heat-shield pressure coefficient, and enhanced heat transfer throughout the re-entry vehicle.

Sabapathy, Santhosh

Aircraft Surface Coating Interaction with Aircraft Deicing/Anti-Icing Fluids

AIR6232 (Current)

6/10/2026

This SAE Aerospace Information Report (AIR) provides descriptions of test methods for determining if an aircraft surface coating of any thickness has adverse effects on aircraft deicing/anti-icing fluids with respect to fluid holdover time performance and aerodynamic performance. Although not the primary mandate of the G-12 Aircraft Ground Deicing Committee, this document also provides descriptions of suggested test methods for evaluating aircraft surface coatings with respect to durability, hardness, weathering, aerodynamic drag, ice adhesion, ice accumulation, contact angle, and thermal conductivity. These additional tests can provide informational data for characterizing the coatings and may be useful to operators when evaluating the coatings.

G-12ADF Aircraft Deicing Fluids

An Investigation on Eppler 387 and Selig 1223 Airfoils Integrated Wing Section for Solar-Powered Unmanned Aerial Vehicle

2026-01-5035

6/3/2026

This study examines the aerodynamic performance of a wing section incorporating high-lift airfoils for use in a solar-powered Unmanned Aerial Vehicle (UAV) operating at low speeds. This paper evaluates the aerodynamic performance of a wing section integrated with high-lift airfoils for application in a solar-powered UAV. The primary objective is to simulate low-speed flight conditions representative of solar-powered UAV missions in order to obtain relevant aerodynamic parameters by adopting Eppler 387 and Selig 1223 airfoils. Experimental and Numerical simulations are performed over a range of angles of attack to systematically assess key aerodynamic coefficients, including the coefficient of lift (Cl), coefficient of drag (Cd), and coefficient of pressure (Cp) to sustain the flight physics and steady level flight. A scaled prototype of the wing section is experimentally evaluated in a low-subsonic wind tunnel to validate the computational results under low-speed operating conditions. An insightful study on the distribution of static and dynamic pressure over the wing surface is analyzed using computational fluid dynamics (CFD) techniques to quantify aerodynamic performance. The Eppler 387-Selig 1223 twin-airfoil wing section attained the coefficient of lift Cl = 1.89 at 13° angle of attack (α), and it is suggested to utilize it for commercial solar-powered UAVs at low-speed operating conditions.

D., Lakshmanan, Swaminathan, Selvam

Q&A

26AUTP06_14

6/1/2026

Neural Concept is an AI-first engineering platform that is being used at OEMs, including Subaru, Jaguar Land Rover (JLR) and General Motors. The company, which grew out of the Swiss Federal Institute of Technology Lausanne in 2018, is applying AI in real aerodynamic engineering workflows, visualized through NVIDIA Omniverse. Today, the company has 120 employees and works with companies in Europe, the U.S., India, South Korea and Japan. SAE Media met up with Thomas von Tschammer, managing director of Neural Concept USA, at WCX in Detroit in April. This has been lightly edited for clarity.

Blanco, Sebastian

Accelerating Aircraft Verification and Certification through an Integrated Virtual and Physical Testing Approach

2026-26-0710

6/1/2026

Aircraft verification and certification entail a variety of testing tasks and require coordination among numerous stakeholders across different disciplines to ensure alignment on requirements. Historically, certification strategies have relied on both physical testing and high-fidelity simulation. The integration of these complementary approaches is essential to address their respective blind spots and to support credible certification evidence. A key challenge lies in the rigorous correlation of simulation models with physical test data. Flutter verification, for instance, is a critical component in defining the aircraft’s flight envelope and plays a foundational role in certifying safe operational boundaries. In this work, the process of freedom from flutter verification is demonstrated. This work introduces a novel approach to combining simulation and test data with the aim to accelerate and streamline the verification process leading to more efficient and cost-effective aircraft development. In addition, it is shown how the flutter verification process can be deployed using a simulation process and data management (SPDM) tool from which tasks are assigned and results are collected allowing transparency about the status of the workflow and providing stakeholders access to the data they need when they need it. The workflow is demonstrated using ground vibration test measurement performed on a full-scale F16 aircraft. Throughout the process, simulation data, test results, requirements, and supporting documentation are systematically managed within the SPDM framework. This enables effective cross domain collaboration between simulation and test engineers while also maintaining a single source of truth for proof of compliance and progressively building a robust digital thread throughout the development lifecycle.

Hallez, Raphael, Yadabettu, Dayanand Kumar, de Boer, Jens, Aspasiou, Vicky

Effect of Strap-On Geometry on the Aerodynamics of Multibody Launch Vehicle

2026-26-0727

6/1/2026

Strap-on boosters play a crucial role in heavy launch vehicles by providing additional liftoff thrust without major changes to the baseline design, enabling launch with existing propulsion systems. However, strap-on boosters introduce additional pressure drag and alter the overall aerodynamics of the vehicle. While efforts have been previously made to derive empirical relationships to predict the aerodynamics of different strap-on configurations, most are case-specific and primarily limited to estimating drag coefficients (CD). The present study focuses on geometric parameters of strap-on such as length, diameter and radial gap between strap-on and core. The results are used to derive an empirical relationship which can be applied during preliminary design stage of a launch vehicle to predict axial force coefficient (CA), normal force coefficient (CN) and pitching moment coefficient (CPM), which are required for mission design and structural load estimation. In the current study, systematic CFD based parametric studies were conducted using Reynolds-averaged Navier-Stokes based in-house solver PARAS 3D. Simulations were performed at transonic (Mach=1.2) and supersonic (Mach=1.8) regimes in pitching condition at an angle of attack 4°. The study considers a simplified configuration with two parallel strap-on boosters. Parameters were evaluated relative to a clean-core baseline configuration. An empirical relation between aerodynamic coefficients and strap-on geometry was derived and were validated against different configurations. The derived relations provide a rapid and practical tool for preliminary aerodynamic assessment of multibody launch vehicles.

Muraleedharan, Archana P., G, Ramana Bharathi, S, Gnanasekar

A Robust 6-DOF Dynamic Soaring Framework Incorporating Variable Aerodynamic Derivatives

2026-26-0771

6/1/2026

Dynamic soaring is a flight technique that exploits wind shear for sustained flight. It is commonly observed in birds such as albatrosses and holds significant potential for unmanned aerial vehicle (UAV) missions. Previous research has primarily focused on trajectory generation using direct optimal control or differential flatness. This paper proposes an enhancement to the existing six-degree-of-freedom (6-DOF) trajectory generation method based on differential flatness. The proposed formulation includes sideslip and accounts for all stability and control derivatives. A Vortex Lattice Method (VLM) solver is then used to compute steady aerodynamic forces and moments, which are compared against the constant-derivative-based trajectories. To assess the validity of the constant-derivative assumption, a 6-DOF UAV model is simulated in a dynamic soaring orbit with stability augmentation provided by a Linear Quadratic Regulator (LQR). The observed divergence in this simulation highlights the limitations of the constant-derivative approach. Trajectory generation is then refined by incorporating the variation of aerodynamic derivatives with flight conditions, using data from a lookup table generated using a VLM solver. The effectiveness of this improved approach is demonstrated through simulation results. The main contributions of this work are: (i) a differential-flatness-based dynamic soaring formulation that includes sideslip and full derivative coupling, (ii) a validation framework that exposes limitations of constant-derivative assumptions, and (iii) a lookup-table-based trajectory generation method that enhances stability and realism, providing a practical pathway toward experimentally realizable dynamic soaring trajectories.

Swaminathan, Bharath

Thermo-Structural Analysis of Grid Fins for Re-Entry Modules

2026-26-0749

6/1/2026

Grid fins are non-conventional aerodynamic lifting and control surfaces which are made of a frame supporting lifting surfaces positioned in the form of a lattice structure. Grid fins are also called as lattice fins and are used as control surfaces in launch vehicles, crew escape systems, missiles etc. to achieve static stability. Each panel of the grid fin acts as fin and it produces force which increases stability of the vehicle. For a crew escape system module, grid fins are used as a passive aerodynamic control surfaces to achieve static stability. Grid fins are positioned at the end of crew escape system module to provide required static margin by increasing moment arm. In contrast to conventional fins, grid fins incorporate a distinctive waffle-like pattern or grid pattern configuration, offering superior aerodynamic performance in supersonic regimes and enabling compact storage in stowed position during launch followed by deployment at the time of exigency. In case of an emergency, crew escape system is activated and it will take crew escape module away from the launch vehicle during atmospheric regime. In this scenario, grid fins are deployed simultaneously along with firing of high-thrust, fast-acting solid rocket motors (SRMs) which provide the impulsive force needed for clean separation. Grid fins help to stabilize the crew escape system module by counteracting aerodynamic instabilities, especially when the module is moving through the atmosphere at high speeds. The primary structural loads acting on grid fins include deployment forces (hinge forces, locking), aerodynamic, and inertial forces. Additionally, the exhaust plumes from the firing of SRMs impinge directly upon the grid fins, generating intense thermal loads characterized by rapid temperature gradients and localized heating. The simultaneous presence of thermal and structural loads influences displacements, stresses, interface joints integrity and maximum buckling loads. Furthermore, elevated temperatures degrade mechanical properties such as yield strength, ultimate strength, and Young’s modulus, therefore a thermo-structural analysis is carried out to study the effects of these combined loads on grid fins. This paper presents typical grid fin configuration, thermo-structural formulation, finite element model details, and thermo-structural analysis results including stress margins, deformations, buckling load factors and preload variations for the maximum design load case.

Mali, Somanath Nandu, Sundar Raj, R, Sundaresan, MK, R, Suresh

Design Optimization of Aircraft Light Optics: Eliminating Fasteners by Flexure-Based Clamp to Mitigate the Crack Formation and Validation through HALT

2026-26-0750

6/1/2026

Aircraft lighting systems play a vital role in ensuring operational safety, visibility, and regulatory compliance. Exterior lighting systems are essential for aircraft identification, navigation, collision avoidance, and ground operations under varying environmental conditions. These systems typically include navigation lights, anti-collision lights, landing and taxi lights. An aircraft lighting system comprises light sources, optical elements, electronic control units, power interfaces, wiring harnesses, and mechanical mounting structures. Among these components, optics are critical as they control light distribution, intensity, color accuracy, and efficiency while withstanding harsh aerospace environments such as vibration, thermal cycling, and aerodynamic loads. Aircraft exterior lights are subjected to severe thermo-mechanical stresses due to aerodynamic loading, vibration, and thermal cycling. The use of high-performance optical polymers such as Cyclo Olefin Polymers (COP) provides excellent light transmission and stability; however, their relatively lower mechanical toughness makes them susceptible to stress-induced cracking during assembly. In the baseline configuration, the Circuit Board Assembly (CBA) was fastened directly onto the optic using self-tapping screws. During assembly, frequent crack initiation was observed in the optic around the fastener locations, leading to concerns regarding reliability and maintainability. To address this issue, a redesigned mounting approach was developed that eliminated direct fastener penetration into the optic. Instead, the CBA is retained using a precision clamping mechanism, thereby distributing assembly loads uniformly and avoiding localized stress concentrations. COP material was retained due to its superior optical characteristics and compliance with photometric requirements for aircraft lighting applications. The redesigned optic-CBA interface was validated through Highly Accelerated Life Test (HALT), incorporating combined vibration, temperature, and thermal shock profiles. Test results confirmed that the new clamping design prevented crack formation, improved mechanical robustness, and ensured long-term optical performance. This paper presents the problem definition, root cause analysis of fastener-induced cracking, the design rationale for adopting a clamp-based mechanism, and detailed HALT validation results. The study highlights the importance of integrating material properties, fastening strategies, and environmental testing in the design of aerospace lighting systems. The proposed design methodology provides a pathway to enhance reliability and lifecycle performance of critical optical components in aircraft applications.

Vialta, Frederico, S, Nikhil, Katageri, Praveen, SP, Pradeep, Singh, Abhimanyu Kumar

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