Browse Topic: Aerodynamics

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Structural Robustness and Regime-Dependent Uncertainty in a Reduced-Order Physics Model for Vehicle Fuel Consumption Using Monte Carlo Analysis2026-24-0015To be published on 09/21/2026
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
Gutierrez, Marcos, Taco, Diana
Aerodynamic Disc Brake Drag: An Elusive Source of Variability2026-01-0802To be published on 09/14/2026
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 experimentally 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
Further Investigation of Brake Squeal: Effect of (Inboard/Outboard) Pads Property Differential2026-01-0799To be published on 09/14/2026
It was reported earlier that the wear differential between the inboard pad and the outboard pad leads to brake squeal generation. The (I/O) 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 properties of the pads although the pad formula may be the same. The current investigation focuses on the pad property issues. It is found that pad compressibility differential and pad hardness differential are closely related to brake squeal generation. The property differentials are caused by pad porosity variations. The implications of hardness differential on friction/vibration will be discussed.
Zou, Tianlang
Design considerations for optimizing the wheel bearing outer ring bolt‑mounting pattern for reduced drag2026-01-0830To be published on 09/14/2026
Electric vehicles (EVs) place unique and demanding requirements on wheel bearing systems due to their increased vehicle mass, higher torque output, and the need for improved energy efficiency to maximize driving range. These factors elevate the loads transmitted through the bearing‐to‐knuckle joint, often necessitating higher clamp loads to maintain joint integrity. However, increased clamp loads can amplify wheel bearing outer ring distortion, leading to higher rotational drag and reduced bearing durability. Managing and minimizing outer ring distortion is therefore critical for EV wheel bearing design, as well as for high‑performance vehicles that experience extreme 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 conducted to evaluate the influence of various
Mandhadi, Chaitanya Reddy, Lee, Seungpyo, Bovee, Benjamin, Callaghan, Kevin
Optimization of Hydraulic Disc Brake Caliper Parameters to Achieve Near Zero Residual Drag in Two-Wheeler Brake Systems2026-01-0820To be published on 09/14/2026
Residual drag in hydraulic disc brake systems is an inherent phenomenon caused by elastic deformation of piston seals, geometric tolerances, and frictional interaction between piston, seal, and brake pads. Even minimal unintended pad-to-disc contact after brake release can generate residual torque, leading to increased rolling resistance, temperature rise, accelerated pad wear, and reduced vehicle efficiency. With growing emphasis on performance optimization and energy efficiency in two-wheeler applications, minimizing brake drag without affecting braking response has become an important design objective. This paper presents the design, analysis, and experimental validation of a zero-drag floating brake caliper concept developed to reduce residual brake torque through optimization of piston seal characteristics and groove geometry. The study focuses on understanding piston rollback behavior as the primary mechanism governing pad clearance after pressure release. Analytical evaluation
Badade, Ashish Laxman
Biomimetic Design and Numerical Analysis of a VIV Suppression Fairing for Offshore Risers2026-99-1640To be published on 07/24/2026
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
Zhang, Xu, Song, Guangming, Wang, Baozhong, Zhao, Jinpeng, Chen, Qianshuo
Optimization Design and Performance Verification Method of Antiaircraft Gun Fuze2026-99-1630To be published on 07/24/2026
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 Transport2026-99-1626To be published on 07/24/2026
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
Study on the Aerodynamic Characteristics of Canard Configuration Missile Influenced by Aileron2026-99-1610To be published on 07/24/2026
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
Zhang, Zilun, Xu, Jiasheng, Mei, Zhiwei
Flight Test Analysis Method for Aerodynamic Characteristics of Helicopter Rotor in Level Flight2026-99-1821To be published on 07/17/2026
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
Zhao, Jingchao
Numerical Simulation Study on the Transformation Process of Multiple Droplets into Liquid Films2026-99-1833To be published on 07/17/2026
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
Huo, Ye, Chen, Yongheng, Sun, Cunxiang
Guidance Law Design and Simulation Verification for Multi-Missile Cooperative Attack of UAVs2026-99-1813To be published on 07/17/2026
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
Research and Analysis on Convergence in Hypersonic Slip Flow Numerical Simulation2026-99-1805To be published on 07/17/2026
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
Hu, Junlin, Wang, Yaping, Gao, Yunguang, Wan, Lv, Pan, Sha
Load Analysis of Flap and Slat Actuators in Aircraft High-Lift Systems2026-99-1802To be published on 07/17/2026
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
Xu, Yuanze
Aerodynamic Optimization Method Based on a Hierarchical Adaptive Activation Function Neural Network2026-99-1823To be published on 07/17/2026
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
Liu, Di, Wang, Yongfeng, Wen, Hong, Wei, Yuanhang, Ma, Hengwei, Zhao, Runhui
Ground Vehicle-Mounted Testing of UAV Aerodynamic Forces2026-99-1818To be published on 07/17/2026
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 Aerodisk2026-99-1841To be published on 07/17/2026
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 Aircraft2026-99-1837To be published on 07/17/2026
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 Clustering2026-99-1858To be published on 07/17/2026
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
Tang, Longhao, Sun, Xiaoxu, Liu, Changlin
Dynamic Characteristics Study of the Deployment Process of Aircraft Folding Wing2026-99-1860To be published on 07/17/2026
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
Wei, Ting, Tong, Zongkai, Li, Naitian
Data Fusion Techniques for Optimizing Motorsport Aeromap Generation: A Survey2026-01-50587/7/2026
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
Ongley, Thomas James Henry, Teschner, Tom-Robin, Ashton, Neil, Siampis, Efstathios
From Wind Tunnels to an AI-Supported Data-Driven Development Ecosystem2026-01-07677/1/2026
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
Jacob, Jan D.
Numerical Investigation of Inverted Airfoils in Ground Effect for Motorsport Applications01-19-01-00046/25/2026
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
Chowdhury, Rohan, Shukla, Dhwanil
Effect of Static Fin on the Stability and Aerothermodynamic Characteristics of the Re-entry Vehicle01-19-01-00036/11/2026
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 FluidsAIR6232 (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 Vehicle2026-01-50356/3/2026
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
D., Lakshmanan, Swaminathan, Selvam
A Robust 6-DOF Dynamic Soaring Framework Incorporating Variable Aerodynamic Derivatives2026-26-07716/1/2026
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
Swaminathan, Bharath
Thermo-Structural Analysis of Grid Fins for Re-Entry Modules2026-26-07496/1/2026
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
Mali, Somanath Nandu, Sundar Raj, R, Sundaresan, MK, R, Suresh
Effect of Strap-On Geometry on the Aerodynamics of Multibody Launch Vehicle2026-26-07276/1/2026
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
Muraleedharan, Archana P., G, Ramana Bharathi, S, Gnanasekar
Investigation of Acoustic Fill Effect of a Launch Vehicle Payload Fairing2026-26-07596/1/2026
The payload fairing of a launch vehicle is subjected to extremely high acoustic loads, with peak levels occurring during lift-off and transonic aerodynamic regimes. The external acoustic field penetrates the fairing, producing intense internal sound pressure levels that can challenge the integrity of spacecraft components. Accurate characterization of the vibroacoustic behavior of the payload fairing and its enclosed cavity is therefore essential to ensure spacecraft survivability. The internal acoustic field is governed by the coupled dynamics of the fairing structure and the spacecraft configuration, making it critical to quantify the acoustic environment for different payload arrangements. This study presents a detailed vibroacoustic analysis of a payload fairing with multiple spacecraft configurations to evaluate the resulting internal sound pressure distribution. Vibroacoustic finite element analysis is employed in the low frequency range, while statistical energy analysis is
S R, Arun Raj, Jayan, Mahind, George, P
Accelerating Aircraft Verification and Certification through an Integrated Virtual and Physical Testing Approach2026-26-07106/1/2026
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
Hallez, Raphael, Yadabettu, Dayanand Kumar, de Boer, Jens, Aspasiou, Vicky
Design Optimization of Aircraft Light Optics: Eliminating Fasteners by Flexure-Based Clamp to Mitigate the Crack Formation and Validation through HALT2026-26-07506/1/2026
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
Vialta, Frederico, S, Nikhil, Katageri, Praveen, SP, Pradeep, Singh, Abhimanyu Kumar
Inflow-Dependent Sensitivity of Layout Optimization Performance: A Case Study of the Lillgrund Wind Farm2026-99-17385/22/2026
Layout optimization is one of the most effective approaches to reduce the power loss induced by turbine wakes. However, the performance of a wind farm is strongly affected by the inflow direction. This paper conducted a sensitivity analysis on a realistic wind farm, Lillgrund Wind Farm, to investigate the sensitivity of inflow direction on the power production of the initial layout and optimal limits. A wake model considering ambient turbulence intensity is adopted together with the wake superposition method to efficiently resolve the flow field in the wind farm. The results indicate that the power production of the initial layout had a significant discrepancy under different inflow directions, and relies on the consistency of inflow direction and layout array directions. The feature of the two main directional sectors is observed from a realistic wind rose. Therefore, two-sector wind roses are adopted in optimization, and the angles of sectors vary among 51 cases. After optimization
Yang, Kun, Deng, Xiaowei
Aerodynamic Performance and Wake Characteristics of Floating Offshore Wind Turbine under Pitch Motion2026-99-17155/22/2026
In actual marine environments, the aerodynamic behavior and wake properties of floating offshore wind turbines (FOWTs) are largely shaped by the pitching movement of their supporting platforms. The present study examines the aerodynamic performance and wake characteristics of a complete wind turbine system, encompassing its blades, nacelle, and tower, through the application of computational fluid dynamics (CFD) and the overset mesh method. This paper conducts an in-depth examination of how the amplitude and period of pitching motion influence the aerodynamic loads and flow field associated with wind turbines. The power and wake velocity results calculated in the study are compared with those obtained from numerical simulations by other researchers. The results indicate that the mesh and simulation parameters employed in this research precisely capture the aerodynamic characteristics and flow field surrounding the turbine. This work deliberates on how the amplitude and period of pitch
Chen, Wei, Chen, Jian, Chen, Ye, Sun, Haiying
Aerodynamic Load Characteristics of Maglev Trains in Tunnel Operation Scenarios2026-99-17295/22/2026
High-speed maglev trains are recognized for their superior velocity, environmental benefits, and enhanced passenger comfort, positioning them as a key area of interest in modern transport research. Nonetheless, tunnel operations introduce complex aerodynamic challenges that can impede performance. This research examines the aerodynamic load behaviors of maglev trains in single and double-track tunnel settings, with particular emphasis on transient drag variations in lead and trail cars during solo and passing operations. A computational fluid dynamics model was constructed to capture detailed flow field attributes, including pressure wave propagation, reflection, and superposition. Findings indicate that aerodynamic loads intensify with increasing speed. When velocity rises from 300 km/h to 600 km/h during solo tunnel transit, the lateral force on the head-car and the drag on the trail-car both surge approximately fivefold. During meets in double-track tunnels, the head-car’s lift
Zhu, Fentian, Ma, Yamin, Zhang, Yaowen, Yuan, Yeping, Gong, Peilin, Niu, Jiqiang
Computational Analysis of Platform Motion and Wave Effects on the Aerodynamics and Wake of the IEA 22 MW Floating Wind Turbine2026-99-17355/22/2026
This study investigates the unsteady aerodynamic response, wake evolution, and vortex dynamics of an ultra-large floating offshore wind turbine (FOWT) under coupled motion–wave conditions. A high-fidelity aero–hydrodynamic CFD model is employed for the IEA 22 MW reference turbine. Platform pitch and surge motions are prescribed via sinusoidal functions, and wave conditions are independently introduced by considering two representative sea states (H = 4 m and 7 m) and a no-wave case. Results show that pitch and combined pitch–surge motions significantly amplify unsteady aerodynamic effects, increasing peak power from 81.1 MW (P5S0) to 92.6 MW (P5S5), with periodic negative power output and severe dynamic stall. Under strong motion, waves further raise peak power to 93.4 MW (H7P5S5), indicating a coupled amplification effect. Dynamic stall is mainly triggered by pitch motion, expanding in scope and duration with motion amplitude; wave effects on stall remain limited. Platform motion also
Xie, Bin, Sun, Haiying, Chen, Ye
The Aerodynamic Performance of Lotus EMEYA15-19-02-00075/18/2026
In this article, the aerodynamic features of two configurations of Lotus EMEYA are introduced. The first configuration includes a fixed air dam and an active rear spoiler (ARS) assembly, which has two active blades in order to obtain the aerodynamic drag and lift performance required. The second configuration includes an Active Air Dam (AAD) assembly and a gurney flap mounted on the ARS in order to achieve more aggressive aerodynamic performance. The aerodynamic bandwidths and the lift balances of both configurations are demonstrated, and the strategies of active aero components of the two configurations are also introduced. Through active aerodynamics and control strategies, the two configurations of Lotus EMEYA can meet the performance requirements of users in different scenarios.
Yuan, Qingpeng, Yang, Lei, Li, Bo, Ni, Li, To, Chi Hin, Xiong, Zhenfeng
A Deep Learning Framework for Fast Prediction of Automotive Drag and Pressure Fields2026-99-07485/15/2026
Computational fluid dynamics (CFD) is crucial for automotive design, requiring analysis of 3D point clouds to investigate how vehicle geometry affects pressure fields and drag. Running CFD on high-resolution 3D geometry quickly becomes computationally heavy, and many solvers slow down noticeably as the geometric detail increases. We therefore introduce a dual-task deep learning framework, named AeroFormer, that predicts aerodynamic quantities directly from the vehicle’s surface geometry and avoids the need for full CFD simulations. The model is organized into two parts. One branch, AeroFormer-Cd, predicts the overall drag coefficient (Cd), while the other, AeroFormer-Press, reconstructs the pressure distribution over the vehicle’s surface. Both branches rely on a shared curvature-guided adaptive sampling process and a physics-aware attention encoding module, which enable the network to emphasize fine geometric details in aerodynamically sensitive regions such as the front bumper, A
Yan, Shengmao, Deng, Shisong, Jiang, Yanzhen, Jin, Xinyu, Cai, Zhengyang
An Energy-Saving Coupling-Decoupling Optimization Strategy for Electric Modular Buses Considering Vehicle to Vehicle Charging2026-99-07305/15/2026
As an emerging innovative mode of public transportation, electric modular buses (EMBs) offer a novel solution to the problems of existing public transportation systems, due to the coupling-decoupling processes. In this paper, we study the energy consumption characteristics of EMBs by joining vehicle-to-vehicle (V2V) charging and reduction in aerodynamic drag due to coupling. For the pursuit of energy economy, ride comfort, and operational efficiency, we constructed an optimization scheme based on the simulated annealing (SA) algorithm to facilitate the coupling-decoupling process. The simulation results show that EMBs can meet 82.5 % of service requests compared with 61.8 % for the benchmark group, and V2V presents a significant contribution to energy efficiency, especially at low battery state of charge (SOC). Additionally, sensitivity analysis is conducted to study the impact of initial SOC, operation interval, and route type. The results provide insights for optimizing EMBs
Liao, Peng, Guo, Jiahe, Ning, Donghong, Li, Sijia, Wang, Tao
Design of a Novel Intelligent Monitoring Platform for Low and Medium Altitudes2026-99-07395/15/2026
This paper presents the design of a novel intelligent monitoring platform for low and medium altitudes, aiming to offer a new solution for the development of intelligent equipment operating in this airspace. Current monitoring tasks are primarily performed by fixed-wing and multi-rotor UAVs, but these platforms face significant technical bottlenecks in flight endurance and monitoring precision. This research aims to address these deficiencies. The platform is based on a small-scale unmanned airship featuring a semi-rigid, hybrid lift-body structure. Improvements were made upon the traditional ellipsoidal hull; the hull profile was optimized using a geometric superposition method, introducing an aerodynamic camber line with a maximum camber (m) of 4% to enhance aerodynamic performance at small angles of attack. In terms of its energy system, the platform is powered by a purely electric energy system composed of solar panels and batteries; solar energy is used during the day, while
Song, Ziang, Gao, Wenxuan, Cao, Xiaochuan, Zheng, Xing, Zhao, Chong
Truck and Bus Coastdown ProcedureJ2978_202604 (Current)4/28/2026
This document describes a rigorous engineering test procedure that utilizes industry-accepted data collection and statistical analysis methods to determine the road load and to estimate the aerodynamic drag area of trucks and buses weighing more than 10000 pounds. The test procedure may be conducted on a test track or on a public road under controlled conditions and supported by extensive data collection and data analysis constraints. The estimated aerodynamic-drag-area result represents a single-speed and single-yaw-angle condition. Test results that do not rigorously follow the method described herein shall not be represented as an SAE J2978 result.
Truck and Bus Aerodynamics and Fuel Economy Committee
Real Turbulent Flow in Vehicle Aerodynamics: Overview of On-Road Measurements and Turbulence Generation in Wind Tunnels2026-01-50294/22/2026
Flow conditions on the road are quite different from the conditions used to develop vehicle aerodynamics. However, a significant amount of statistical data now exists that describes realistic road conditions. Some of these on-road flow characteristics can be replicated in wind tunnels. This paper reviews technical facilities designed to simulate on-road flow characteristics, such as turbulence intensity, turbulent length scales, and flow angle distribution. Reconstruction of a flow field that matches real road conditions is made possible by using active or passive turbulence generators within the wind tunnel. This review provides a comprehensive overview of these facilities, offering readers key insights into the challenges involved in replicating real-world flow conditions in wind tunnels.
Vondruš, Jan, Vančura, Jan
Enhancing the Aerodynamic Performance of Diffusers in High-performance Vehicles Using Trapped Vortex Cavities2026-01-50274/9/2026
Motivated by the inclusion of active flow control provisions in the 2026 Formula One regulations, and building upon previous studies of Trapped Vortex Cavity (TVC) implementation in inverted front wings, this paper investigates the effectiveness of TVC as a flow control mechanism applied to vehicle diffusers. Both active and passive configurations were considered for three diffuser geometries: a base straight-line diffuser, an inverted airfoil-shaped diffuser, and a diffuser inspired by a Formula One car. The study employed numerical simulations to evaluate the aerodynamic performance and the potential benefits of integrating TVC systems. Across all types of diffusers, the implementation of a circular TVC cavity resulted in a significant improvement in the lift-to-drag ratio (CL/CD). In the active flow control configuration, a 10% improvement was observed in the straight diffuser under a limited mass-flow rate. With optimized cavity positioning and radius, the airfoil-shaped and
Ming Kin, NG, Teschner, Tom-Robin
A Correction Method to Estimate Wake Effects for Aerodynamic Performance Metrics2026-01-06014/7/2026
Wake effects modify the aerodynamic performance of a road vehicle when driving in traffic. Analysis of wind-tunnel measurements conducted in flows with wake characteristics, using a traffic-wake-simulation system, suggests that conventional uniform-wind performance coefficients can be scaled, using wake-flow-field information, to predict the influence of wake effects. This paper presents a flow-field-averaging method that estimates a dynamic-pressure correction and yaw-angle correction for application to uniform-wind data, to account for changes in performance due to wake effects. This first-order method is shown to provide reasonably-good accuracy when reverse correcting the wind-tunnel wake-effects measurements. Drag-coefficient data for light-duty-vehicle models, which showed wake effects exceeding 20%, were corrected to within 5% of uniform-wind values, while data for heavy-duty-vehicle models, which showed wake effects exceeding 15%, were corrected to within 2% of uniform-wind
McAuliffe, Brian
Wind-Tunnel Study of the Traffic-Wake Impacts for Road-Vehicle Aerodynamics2026-01-06134/7/2026
When driving in traffic, the wakes of leading vehicles reduce the wind speed experienced by a following vehicle, lowering its drag relative to isolated driving. These wake effects can persist to large inter-vehicle distances, on the order of hundreds of meters, while lateral convection due to cross winds can influence vehicles in adjacent lanes. Wind tunnel testing was conducted at 30% scale for light- and heavy-duty-vehicle models in a large wind tunnel with a traffic-wake simulation system, expanding upon a previous study that examined only heavy vehicles. Three variants of the DrivAer model, four variants of the AeroSUV model, and three variants of a zero-emission heavy-duty-truck model were tested with a range of simulated wake conditions that varied the type, forward distance, and lane position of the wake-source vehicle(s), for a range of yaw angles up to 11°. Results show drag reductions of up to about 10% for the heavy-duty-truck model, and up to about 20% for the passenger
McAuliffe, Brian, Ghorbanishohrat, Faegheh, Barber, Hali
Parametric Aerodynamic Design and Development of a Formula 1 2026 Front Wing with Wind Tunnel Validation2026-01-06464/7/2026
The front wing of a Formula 1 car is one of the most important aerodynamic components in design development. Particularly, as it is the first to interact with the upcoming airflow, the aerodynamic flow structures generated will have a strong interaction with the remainder of the car’s components. In 2026, the Fédération Internationale de l’Automobile will introduce new regulations that incorporate new aerodynamic philosophies for the front wing, including active aerodynamics. This paper presents a design methodology study for the development of a Formula 1 2026 front wing, compliant with Issue 9 of the technical regulations. A computational-based, structured optimisation series was conducted to enhance the aerodynamic performance of a front wing concept with a focus on improving downforce, maximising efficiency, and enhancing trailing flow for the remainder of the car. The final front wing concept at 40%, running at 30 m/s, generated 189 N of downforce and 19 N of drag. Active
Jacoulot, Santiago, Soares, Renan F., Marshall, David W.
Study of the Vortex Flow over a Generic Open-Wheel Race-Car2026-01-06494/7/2026
Open wheel race cars present a challenge to the aerodynamic designer because of the numerous wakes and vortices created by the various body components. The present study follows the development of a high-downforce race car and investigates possible vortex manipulations to increase its aerodynamic efficiency. The tools used for this study involved computational fluid dynamics and small-scale wind tunnel testing. Once the basic geometry of the racecar was finalized, cost effective measures were tested to improve its downforce to drag ratio. As an example, by fine tuning the position of different body components, such as the rear wing location relative to the underfloor diffuser exit, vehicle’s aerodynamic performance can be modified. The results of both the wind tunnel and the computational investigations indicated that such simple modifications can positively improve the race-car downforce to drag ratio. Also, once the baseline vehicle’s geometry was frozen and observing that the
Okpysh, Christian, Katz, Joseph, Shute, Robin
The Development of an Experimental Methodology for the Measurement of Aeroelastic Components2026-01-06484/7/2026
In high-end motorsport engineering, aerodynamic devices such as front and rear wings are prone to aeroelastic deformations under certain conditions, which can be exploited for vehicle performance gains. Considering the complex interactions between the aerodynamics and structures, experimental evaluation can prove to be a time-effective approach for design, optimisation, research and development regarding aeroelastic bodies. This study presents the development and experimental validation of a deformation tracking system using depth-sensing LiDAR (Light Detection and Ranging) camera technology. The system is based on the use of reflective markers mounted on a given model of interest; this project, a front wing model with a flexible, 3D printed flap element was used as a benchmark. Surface deformation is captured by post-processing point cloud data to extract three-dimensional displacement vectors. A series of controlled measurement tests were first conducted to assess accuracy and
Altinbas, Koray, Soares, Renan F.
Extreme Scale Automotive Aerodynamic Simulations2026-01-05974/7/2026
Achieving an optimal balance between simulation accuracy and computational efficiency remains a central challenge in automotive aerodynamics. While the adoption of AI and machine learning (ML) methods in vehicle development is expected to grow significantly, the demand for highly scalable, computationally efficient, and accurate computational fluid dynamics (CFD) methods persists. The emergence of GPU (graphics processing unit) technology presents new opportunities to deliver cost-effective, high-fidelity, scale-resolving simulations to industrial users. A comprehensive evaluation of Simcenter STAR-CCM+’s parallel scalability and accuracy across extensive CPU and GPU resources was executed on the Frontier supercomputer at Oak Ridge National Laboratory (ORNL). Steady-state and transient aerodynamic scalability simulations were executed using the DrivAer notchback vehicle configuration. Simulation accuracy was evaluated through transient simulations employing the SST-DDES turbulence
Larsson, Torbjörn, Grover, Ronald O., Landi, Simone, Altmann, Peter, McManus, Liam, Dowding, Steven
Aerodynamic Proximity Effects between the DrivAer and AeroSUV Standard Models, Part 2 – Adjacent-Lane and Lateral-Offset Interactions2026-01-06064/7/2026
Aerodynamic interactions between two 30%-scale passenger vehicles in close proximity were examined experimentally in a large wind tunnel, with a focus on longitudinal separations up to two vehicle lengths, lateral separations up to one lane width, and combinations thereof. Part 1 of this paper described the longitudinal following (platooning) configurations of these results, while this paper concentrates on adjacent-lane influences and lateral-offset effects when platooning at a single separation distance. Test models were based on the DrivAer and Aero-SUV open-access geometries, each with slant-back (Notchback or Fastback) and square-back (Estateback) variants. This provided four distinct model pairings, not all of which were tested in each positional arrangement. Adjacent-lane results matched the trends from a smaller-scale study in a different wind tunnel using the same geometry pair, with small-but-distinct differences attributed to different blockage ratios in the two wind-tunnel
McAuliffe, Brian, Ghorbanishohrat, Faegheh
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