Browse Topic: Aerodynamics

Items (7,112)
Find
Evaluating the Impact of Drag Coefficient Changes on Driving Energy Using a Probability Distribution Model of Yaw Angle Based on Empirical Data from North American Highways2026-01-0615To be published on 04/07/2026
This study estimates the impact on driving energy of differences in aerodynamic characteristics for yaw angle from natural wind during North American Highway mode driving. A previous study[1] clarified the potential to estimate the fuel consumption impact of natural wind by integrating the CD yaw characteristics and yaw angle occurrence frequency. The natural wind was measured on a vehicle while driving a representative North American Highway test course[2]. The driving energy is predicted from the obtained yaw frequency and CD yaw sweep data in a wind tunnel. Measurements were conducted every weekday for 8 hours in 2023, covering 70% of the traffic volume. The validity of the measurement period was evaluated by the deviation from the annual average of wind direction and speed. Since yaw frequency varies depending on the road environment, it is necessary to weight the road environment type frequency when calculating the driving energy. The frequency was calculated using machine
Onishi, Yasuyuki, Nucera, Fortunato, Nichols, Larry, Metka, Matt
A Correction Method to Estimate Wake Effects for Aerodynamic Performance Metrics2026-01-0601To be published on 04/07/2026
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
Aerodynamic Proximity Effects Between the DrivAer and AeroSUV Standard Models, Part 1 – Same-Lane Interactions2026-01-0605To be published on 04/07/2026
Road-vehicle platooning is traditionally defined as close-distance longitudinal following in laterally-aligned formation. In this paper, the effects of aerodynamic interactions on the drag of a two-vehicle system are examined by considering the influence of separation distance, cross winds, vehicle size and shape. Testing was undertaken at 30% scale in a large wind tunnel with road-representative freestream turbulence. Separation distances of 0.5, 1.0, and 2.0 vehicle lengths were examined over a range of yaw angles between ±15deg. A highlight of the current study is the characterization of platoon drag-reduction benefits for different sizes and shapes of the lead and follower models, by using a DrivAer model and an AeroSUV model, each with slant-back (Notchback or Fastback) and square-back (Estateback) variants, providing four distinct model pairings. Drag reduction for the lead model appears to be affected mainly by the size of the follower vehicle, while the follower model shows a
McAuliffe, Brian, Ghorbanishohrat, Faegheh
Wind-tunnel investigation of snow/ice drag on a 30%-scale DrivAer model2026-01-0604To be published on 04/07/2026
Wind-tunnel tests were conducted using a 30%-scale DrivAer model, in estateback and notchback rear-geometry configurations, to investigate aerodynamic performance changes associated with snow and ice buildup on passenger vehicles. Around 20 snow/ice accumulation patterns were tested, at a Reynolds number of 2.8 million based on model wheelbase, for each of the notchback and estateback variants. 5 additional patterns were tested on the estateback with roof-rack support bars. Snow accumulation was modelled with foam, while ice accumulation was simulated with aluminum tape hand-formed to the desired shape. A simulated full-scale snow thickness of 58 mm on the hood, roof and trunk increased the wind-averaged drag coefficient by 16% for both model variants. With 90 mm of snow, the drag of the estateback variant increased by 19%. Drag changes increased with, but were not proportional to, snow thickness. Chamfered front and rear edges, representing windblown shapes, reduced the drag penalty
de Souza, Fenella, McAuliffe, Brian
Experimental Validation of a Multi-Row Tapered Roller Bearing Analytical Model for Relating Preload to Frequency Response Characteristics2026-01-0008To be published on 04/07/2026
Roller bearings are used in many rotating power transmission systems in the automotive industry. During the assembly process of the power transmission system, some types of roller bearings (e.g., tapered roller bearings) require a compressive preload force. Those bearings' rolling resistance and lifespan strongly depend on the preload set during the installation process. Therefore, accurate setting of the preload can improve bearing efficiency, increase bearing lifespan and reduce maintenance costs over the life of the vehicle. A new method for bearing preload measurement has shown potential for both high accuracy and fast cycle time using the frequency response characteristics of the power transmission system. An open problem is experimental validation of the multi-row tapered roller bearing analytical model. After validation, the analytical model can be used to predict the assembled system damped natural frequency for a desired bearing preload. This work presents the experimental
Gruzwalski, David, Mynderse, James
Development and Application of CAE Methods for Predicting Snow Accumulation on Floor Undercovers During Snowy Road Driving2026-01-0482To be published on 04/07/2026
The automotive industry is increasingly challenged to address environmental concerns, particularly the goal of achieving carbon neutrality (CN). Japan has committed to CN by 2050 and aims for 100% electric vehicle (EV) sales by 2035. A key factor influencing EV adoption is driving range, which is significantly affected by driving resistance—especially aerodynamic drag. Underbody covers (undercovers) are widely used to improve aerodynamic performance, but they are exposed to various environmental stresses, including water intrusion, stone chipping, and snow accumulation during winter driving. While previous studies have effectively simulated water and chipping stresses, research specifically targeting snow stress has been limited. This study proposes a novel simulation approach to evaluate snow stress on undercovers, focusing on slushy road conditions commonly found in Japan’s snowy regions. A particle-based method was employed to model the interaction between slush and underbody
Matsuura, Tadashi, Annen, Teruyuki, Harada, Takeyuki, Ueno, Shigeki, Asai, Mikio, Watanabe, Haruyuki
Research on Vehicle and Longitudinal Tire Model Parameters Identification Based on Electro-Mechanical Brake System2026-01-0634To be published on 04/07/2026
The Electro-Mechanical Brake (EMB) system is a novel type of brake by wire systems with independently controllable characteristics. This system aids in the decoupling analysis of the vehicle and actuator dynamics, thereby improving the accuracy of parameter identification. Therefore, this paper proposes an innovative parameter identification method for vehicle parameters and longitudinal tire model parameters, based on the characteristics of the EMB system and onboard sensors. First, based on the wind resistance and rolling resistance coefficients obtained from the vehicle coasting conditions, a decoupled constant clamping force sequence braking condition for the front and rear axles is designed by integrating the characteristics of the EMB actuator and vehicle dynamics. This approach enables the identification of vehicle and nonlinear longitudinal tire model parameters, significantly improving the accuracy of parameter identification. Next, considering the nonlinear characteristics of
Huang, Jiayi, Cheng, Yulin, Zhuo, Guirong, Le, Qiao, Wei, Wei, Shu, Qiang
Elucidation of Flow Mechanisms Modulating Vehicle Wind Noise by using Large-Scale CFD Simulation2026-01-0614To be published on 04/07/2026
In vehicle development, noise reduction is critical for ensuring passenger comfort. As electric vehicles become prevalent and engine noise is minimized, wind noise becomes more noticeable. Modulated wind noise, which causes a sense of fluctuation due to atmospheric turbulence, wind gusts, and preceding vehicle wakes, causes significant discomfort. This noise is characterized as a high-frequency sound above 1 kHz, modulated at low frequencies owing to the wind velocity and direction fluctuating at several Hz. However, the mechanisms behind wind noise modulation are not fully understood, and no established countermeasures have been developed. This is because wind noise perceived through the side window is primarily caused by the A-pillar vortex and door mirror wake, which coexist as complex turbulent flows around the vehicle. Therefore, identifying the source of modulated wind noise around vehicles under fluctuating wind conditions is difficult. This study aims to identify the source of
Tajima, Atsushi, Hirata, Takumi, Ikeda, Jun, Kamiwaki, Takahiro, Wakamatsu, Junichi, Tsubokura, Makoto
Investigation of the Blockage Phenomenon in Closed Wall Wind Tunnels During the Testing of Bluff Automotive Bodies with Small Wakes in Yawed Configurations2026-01-0607To be published on 04/07/2026
The difficulties of testing a bluff automotive body of sufficient scale to match the on-road vehicle Reynolds number in a closed wall wind tunnel has led to many approaches being taken to adjust the resulting data for the inherent interference effects. But it has been very difficult to experimentally analyze the effects that are occurring on and around the vehicle when these blockage interferences are taking place. The present study is an extension of earlier works by the author and similarly to those studies uses the computational fluid dynamics analysis of five bodies that generate relatively small wakes to examine the interference phenomena in solid wall wind tunnels and the effects that they have on the pressures, and forces experienced by the vehicle model when it is in yawed conditions up to 20 degrees. This is accomplished by executing a series of CFD configurations with varying sized cross sections from 0.4% to 14% blockage enabling an approximation of free air conditions as a
Gleason, Mark, Riegel, Eugen
Leveraging Large Language Models for CAD Automation and Multi-Objective Optimization of Automotive Heat Exchangers2026-01-0506To be published on 04/07/2026
The design of automotive heat exchangers is a critical challenge, requiring the careful balance of thermal performance, aerodynamic efficiency, structural integrity, and manufacturability. Traditional design processes rely heavily on manual CAD modeling and iterative simulations, which are both time-intensive and computationally demanding. Recent advances in artificial intelligence, particularly in Large Language Models (LLMs) and Transformer-based architectures, open new possibilities for automating these tasks. This work introduces a novel framework that integrates LLMs with CAD kernels to generate parametric heat exchanger geometries directly from natural language descriptions. The models are automatically exported into standard formats for computational fluid dynamics simulations and seamlessly incorporated within a multi-objective optimization pipeline. By coupling natural language-driven CAD automation with advanced optimization techniques, the framework enables rapid exploration
Chaudhari, Prathamesh, Tovar, Andres
Hybrid Computational Tire-Sand Interaction: A Tractive Effort and Rolling Resistance Analysis2026-01-0213To be published on 04/07/2026
This paper investigates the performance of a computational radial passenger car tire over winter road sand at different operating conditions. An experimental direct shear-strength test was conducted using winter road sand to obtain the density, internal friction angle and cohesion. A simulated direct shear-strength test was then validated in a Finite Element Analysis (FEA) software called Virtual Performance Solution (VPS) using a Smoothed-Particle Hydrodynamic (SPH) technique to model the sand. Once the sand was validated against physical testing data the sand was layered atop an icy road surface to understand the influence sand has on tractive effort and rolling resistance performance. With modelled and validated winter road sand and a Continental CrossContact LX Sport tire size 235/55R19, testing conditions were set up. The tire-sand interaction was simulated using a node-to-segment contact algorithm with edge treatment on a low friction surface for both the tire-road and the sand
Fenton, Erin, El-Sayegh, Zeinab
Advancing Electric Drive Unit Design with Smoothed Particle Hydrodynamics (SPH).2026-01-0413To be published on 04/07/2026
The performance of Electric Drive Units (EDUs) in electrified powertrains heavily depends on efficient thermal and lubrication management. Accurate assessment of lubrication flow, particularly in terms of wettability and churning losses, is essential for optimizing EDU performance across various driving conditions. This paper presents a comprehensive numerical investigation of lubrication flow behavior within an EDU using an advanced Smoothed Particle Hydrodynamics (SPH) method. The mesh-free SPH approach provides significant advantages in modeling intricate oil dynamics, such as oil splashing, and the behavior of oil in contact with rotating components. The primary focus of this study is to investigate the phenomena of splashing, wettability, and churning losses under various operating conditions within the gearbox environment. Key flow characteristics such as oil distribution, particle trajectories, torque resistance due to fluid drag, and oil volume fraction are analyzed under
Chintala, Paramesh, Inada, Jorge, Flores Solano, Cesar Alfonso, Gingade, Suresh
26M-00552026-01-0603To be published on 04/07/2026
Since air drag is proportional to the square of the speed, it is expected that reducing air drag will significantly improve fuel efficiency for long-distance trucks and buses, which are often driven at high speeds. Therefore, the purpose of this study is to propose a conceptual shape that will dramatically improve the aerodynamic performance of heavy-duty vehicles, assuming that restrictions on overall length will be relaxed in the future. Using NSGA-II, a genetic algorithm, the overall vehicle shape was optimized with the objective functions CD and CL values and design variables as parameters in a total of 13 locations. Among the Pareto solutions, CD = 0.08 was obtained when the CD value was the lowest. Since the CL value remains low with this shape, it can be seen that driving stability does not deteriorate. Among the design variables in optimization, it was confirmed that the corner radius of the vehicle side was particularly effective in reducing the CD value. In addition, when
Kawano, Daisuke
From CFD Simulations to Machine Learning: A Comparative Study of ML Tools for Aerodynamic Drag Prediction2026-01-0598To be published on 04/07/2026
This study presents the development of machine learning frameworks for predicting aerodynamic drag coefficients in automotive vehicle designs using data derived from computational fluid dynamics (CFD) simulations. The input data includes both structured tabulated design parameters and unstructured geometric representations in the form of point clouds, enabling a multi-modal approach to aerodynamic modeling. A range of machine learning models was explored, from traditional regression techniques to advanced deep learning architectures such as graph neural networks (GNNs), each tailored to handle specific data formats. These frameworks were designed to integrate seamlessly with CFD workflows, supporting efficient training and evaluation using standard regression metrics. The work aims to establish a foundation for data-driven aerodynamic analysis in automotive design, emphasizing the role of machine learning in enhancing simulation-based engineering processes.
Kumar, Gaurav, Khanna, Susheel
Digital Twin Aerodynamics Model Validation for HALO Wind Tunnel2026-01-0610To be published on 04/07/2026
A simulation-based aerodynamics model of the Honda Automotive Laboratories of Ohio (HALO) Wind Tunnel, a three-quarter open-jet (ground plane) configuration opened in 2022 for full-scale automotive testing, is under development to support data fusion for more accurate surrogate models in vehicle engineering programs. The objective is to demonstrate that a matched set of boundary values between the physical wind tunnel and the three-dimensional numerical model yield correct responses for several key flow field quantities, starting with the baseline empty tunnel case: (1) streamwise static pressure distribution, (2) evolution of the free shear layers downstream of the nozzle exit plane, and (3) ground-plane boundary layer development. Pressure-based measurement probes were deployed in these regions using a four-axis overhead traverse to acquire validation data in the large facility, including instrument verification between a 14-hole probe and Pitot-static rake. Detached eddy simulation
Patel, Sajan, Disotell, Kevin, Eagles, Naethan
Automotive Aerodynamics Surrogate Modeling using NVIDIA PhysicsNeMo on Mid-Sized SUV GM Dataset2026-01-0600To be published on 04/07/2026
Aerodynamic simulations are crucial in vehicle design and performance evaluation. Traditionally, these simulations utilize Computational Fluid Dynamics (CFD) techniques to compute flow quantities such as velocity, pressure, and wall-shear stresses. Accurate prediction of these quantities is vital for estimating drag and lift forces, which directly impact fuel efficiency, stability, and acoustics. This study focuses on developing an AI surrogate for aerodynamic design of production mid-size SUVs using NVIDIA’s PhysicsNeMo framework. Firstly, high-fidelity 3D CFD data are generated using first-principles solvers on 100 different geometry variants at a uniform inlet velocity of 38.89 m/s and a fixed set of boundary conditions. The DoMINO (Decomposable Multiscale Iterative Neural Operator) AI model, part of the PhysicsNeMo framework, is then used to train on this dataset, accurately predicting surface pressure and flow fields around vehicles for rapid estimation of critical aerodynamic
Keum, Seunghwan, Raul, Vishal, Grover, Ronald, Parrish, Scott, Ranade, Rishikesh, Ghasemi, Abouzar, Kamenev, Alexey, Tadepalli, Srinivas
An Updated Correlation Study between the Full Size Wind Tunnels of General Motors, Ford Motor Company, and FCA US LLC2026-01-0612To be published on 04/07/2026
As automotive aerodynamic testing facilities evolve to capture more real-world behavior, updating the correlation between old and new technologies is essential. Recently, the three-member consortium of the United States Council for Automotive Research (USCAR) - FCA US LLC, Ford Motor Company, and General Motors - transitioned from full-size static ground plane facilities to 5-belt moving ground plane wind tunnel facilities. The primary objective of this study was to update the correlation data sets to maintain consistent and robust data sharing among companies, which is the cornerstone of USCAR efforts. To achieve this, a set of updated correlation data sets were calculated to replace the original correlation study results from 2008. Additionally, the methodology for applying correlation equations was revised from using averaged wind tunnel data to employing direct wind tunnel-to-wind tunnel correlation equations. In a two-phase correlation effort conducted in 2022 and 2025, the three
Nastov, Alexander, Lounsberry, Todd, Madin, Trevor, Langmeyer, Gregory, Fadler, Gregory, Skinner, Shaun, Horton, Damien
Modelling and Analysis of Rolling Truck Tire over Dry and Snow-Covered Surfaces Using Advanced Computational Techniques2026-01-0591To be published on 04/07/2026
This paper presents a novel approach to modelling and analyzing a 315/80R22.5-sized truck tire under snow-covered road conditions. The tire is modelled using Finite Element Method (FEM) in ESI Virtual Performance Solutions (VPS) software. The tire model consists of various parts representing the tread, under tread, carcass, sidewalls and beads in addition to the rim. The tire model is then verified in both static and dynamic domains against experimental data. The experimental results were conducted over a dry surface at a high-speed test track in Hällered, Sweden, at a constant travelling speed of 80 km/h, and a constant vertical load of 27 kN with sensors depicting both temperature and inflation pressure changes throughout a 40-minute run. A tire thermal model is developed, and the simulation results are correlated with the measured temperature of the tested tires. In addition, the rolling resistance variation with speed, temperature and inflation pressure is predicted and analyzed
Opatha, Dillon, Oijer, Fredrik, El-Sayegh, Zeinab, El-Gindy, Moustafa
Wind-Tunnel Study of the Traffic-Wake Impacts for Road-Vehicle Aerodynamics2026-01-0613To be published on 04/07/2026
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 intervehicle 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 11deg. Results show drag reductions of up to about 10% for the heavy-truck model, and up to about 20% for the passenger-vehicle
McAuliffe, Brian, Ghorbanishohrat, Faegheh, Barber, Hali
Aerodynamic Development of Maruti Suzuki VICTORIS2026-01-0602To be published on 04/07/2026
MSIL (Maruti Suzuki India Limited), India's leader in automotive sector, has various SUVs (Sports Utility Vehicle) in its model lineup. Conventionally, SUVs are considered to have an aggressive stance with a bold on-road presence, and this bold design language often deteriorates aerodynamic drag performance. In the past decade, the demand for this segment has significantly grown, whereas the CAFE (Corporate Average Fuel Economy) norms have become more stringent. To cater to this growing market demand, MSIL planned for a new compact SUV - VICTORIS with targeted best-in-class aerodynamic performance. This paper illustrates the aerodynamic development process for the vehicle using CFD (Computational Fluid Dynamics) and full scale WTT (Wind Tunnel Test). During the initial stages, the bolder design of the VICTORIS deteriorated the aerodynamic drag of the vehicle. Styling exterior surface modifications and addition of new aero parts facilitated the recovery of aerodynamic drag performance
Dey, Sukanta, Singh, Shekhar, Kumar, Chandan, Alphonse, Felix Regin
Quantifying the Impact of Towing on BEV Energy Use: Instrumented On Road Testing and Chassis Dynamometer Reproduction2026-01-0431To be published on 04/07/2026
Electrification is rapidly entering all vehicle classes, including light- and heavy-duty trucks designed for heavy towing capabilities. Still, the quantitative impact of towing on battery-electric vehicle (BEV) energy use and range remains under-characterized. We conducted controlled towing tests with a Ford F-150 Lightning using two trailers of different sizes and varying payloads to isolate aerodynamic and mass effects across the vehicle’s rated towing capacity. The vehicle was instrumented at the CAN bus level to capture motor power, torque, speed, and other related internal signals. On-road testing consisted of repeated back-and-forth passes on level, straight road segments at set speeds focusing on highway operation, where aerodynamic drag is stronger and real-world towing use cases occur. From these data, we extracted road load equations and dynamometer coefficients for each trailer combination, then reproduced equivalent conditions on a four-wheel drive chassis dynamometer
Timermans Ladero, Inigo
From Static Ground to Moving Ground Wind Tunnels: Feature Selection for Reliable Estimation of Drag Coefficient Discrepancies2026-01-0203To be published on 04/07/2026
Moving ground wind tunnels offer a more accurate test environment for ground vehicle drag coefficient measurement due to their highly realistic representation of the boundary layer phenomenon. However, historically most vehicles have been tested on static ground wind tunnels. As a result, the measured drag coefficient of these vehicles may not be sufficiently realistic for certification purposes. Therefore, it is valuable to build statistical models to estimate moving-ground wind tunnel drag coefficient by using information from a static-ground wind tunnel and other relevant vehicle characteristics such as presence of aerodynamic devices (spoilers, air dams, etc.). However, to build accurate statistical models, appropriate predictive features must be identified as a first step. In this paper, an aerodynamic feature selection study has been conducted to identify vehicle characteristics that contribute to drag coefficient estimation discrepancies between a static- and a moving-ground
Singh, Yuvraj, Jayakumar, Adithya, Rizzoni, Giorgio
Time-Step Analysis of Sliding Mesh Rotation Modeling15-19-01-00043/13/2026
The current work analyzes the effect of time-step size on the predictive capability and computational cost of the Sliding Mesh (SM) method for modeling flows around the rotating wheels of a mass-production luxury sport utility vehicle (SUV). Two unsteady turbulence models [Unsteady Reynolds-Averaged Navier–Stokes (URANS) and Delayed Detached Eddy Simulations (DDES)] were tested using time-step sizes ranging from the current recommended time-step size of 1 degree of rotation per time-step (1 D/TS) up to 50 degrees of rotation per time-step (50 D/TS). The flow field predictions compare favorably to the 1 D/TS case for a time-step size as large as 5 D/TS. Using this time-step size leads to a reduction in computational cost of approximately 80% for both unsteady methods. At a time-step of 5 D/TS, the computational cost of the SM method is comparable to the more commonly used Moving Reference Frame (MRF) method. However, drag and flow field predictions by the SM method at this larger time
Struk, Michael, Aultman, Matthew, Disotell, Kevin, Duan, Lian, Bianco, Antonello, Metka, Matthew, Khasdeo, Nitin
Experimental Investigations on Appendages of a Racing Motorcycle2026-01-50112/20/2026
In this experimental work, a detailed analysis of the wind tunnel measurements on scaled motorbike models equipped with different front wings was performed considering four wing configurations operating at different Reynolds numbers and roll angles. Global forces acting on the models were measured by a high-resolution dynamometric balance, while velocity fields in the wake were measured by means of the Particle Image Velocimetry technique. Throughout the paper, overall models’ performances are investigated, demonstrating similar behavior for drag coefficients and various trends for lift coefficients. The without- and single-wing configurations were shown to have positive sign, and conversely, the double- and closed-wing cases—with negative sign—generated downforce due to the presence of significant upward velocities, which in turn modified the wake shape. Furthermore, the improvements in closed-wing configuration compared to without- and single-wing ones were noticeable, while slight
Moscato, Giorgio, Romano, Giovanni Paolo
Understanding Prevailing Physics in Automotive Aerodynamics Applications—Detached Eddy Simulation vs Reynolds-Averaged Navier–Stokes Approach02-19-04-00232/6/2026
This study presents a structured approach to the aerodynamic evaluation of commercial heavy-duty vehicles by categorizing the underlying flow physics into three primary phenomena: pressure-induced separation, geometry-induced separation, and flow diffusion. Furthermore, the study gives insights into the benefits of Detached Eddy Simulations (DES) over traditional Reynolds-Averaged Navier–Stokes (RANS) approaches by analyzing the flow behavior in cases that correspond to these phenomena. Fundamental insights on pressure and geometry-induced separation were developed through simulations of flow over a sphere and a rectangular cylinder at a Reynolds number of 2.8 × 106. Additionally, flow diffusion was investigated using a coaxial jet interacting with surrounding fluid at a Reynolds number of 2.1 × 104. These cases were analyzed using three turbulence modeling techniques: k-ε, k-ω SST, and DES. To demonstrate the practical relevance of these phenomena, a comprehensive aerodynamic
Sankar, Hari, Holay, Sarang, Ikeda, Masami, Singh, Ramanand
The Normalized Lift and Drag as Efficiencies According to the Aerodynamic Equation of State2026-01-60002/3/2026
The wetted surface of a wing induces a three-dimensional pressure distribution onto the surrounding flow field that generates lift. In a similar way, the wetted surface of an aircraft generates parasite drag. Computational fluid dynamics mimics this process by constructing a surface mesh as a grid that recreates the outer mold line (OML) or wetted surface of a wing or aircraft, and used as a geometric reference for calculating the lift and parasite drag. Once the lift and drag are obtained using these physics-based wetted surfaces as geometry references, the legacy lift and drag coefficients are calculated by resorting to the planform area of the wing, and not their aforementioned wetted surfaces. This re-referencing that results from using a planform area instead of a wetted surface results in an overestimation of the lift and drag coefficients that are devoid of a physical meaning and yield misleading results when used to compare the lift or drag of different aircraft. This paper
Burgers, Phillip
Certain Investigations to Improve the Aerodynamic Performance Parameters of a Surface-Modified Airfoil Structure2026-01-60012/3/2026
Flight vehicles operating in low-speed environments face significant aerodynamic challenges due to weak laminar boundary layers, which lead to early flow separation, reduced lift, and increased pressure drag. Airfoils often experience laminar separation bubbles and abrupt stall, making their performance unstable and difficult to predict. This paper aims to address the low-speed aerodynamic parameter analysis using passive flow control techniques on modified NACA 0021 airfoil profile. The novelty of this research method lies in the integration of dimple-based passive flow control structures on the upper surface of a NACA 0021 airfoil specifically designed to delay flow separation and enhance low-speed aerodynamic performance. Unlike most previous studies that focus on conventional vortex generators or active flow control methods, this work uniquely demonstrates that strategically dimple on the airfoil surface modifications significantly improves the lift characteristics. The methodology
Lakshmanan, D., Raman, Senthil Kumar Bella, Sivakumar, Aravinth, Pillai, Balaji Shanmuga
A Rainfield Simulator for Hypersonic Testing26AERP02_072/1/2026
The U.S. Army Space and Missile Defense Command Technical Center's Aerophysics Research Facility, (ARF), fired a successful hypersonic shot to test its new rainfield simulator. U.S. Army Space and Missile Defense Command Technical Center, Huntsville, AL Zack Perrin, ARF manager and technical lead engineer of the U.S. Army Space and Missile Defense Command (USASMDC's) Targets and Test Resources Branch of the Ronald Reagan Ballistic Missile Defense Test Site, said ARF is SMDC's premier hypersonic flight and hypervelocity impact laboratory. Perrin said their largest gun system, the 254 mm light gas guns, or LGGs, is the fastest gun in the Army and can launch projectiles 6 inches in diameter to speeds up to 3 kilometers per second or smaller projectiles on the order of 2.7 inches in diameter to velocities exceeding 6 km/s. “I like to tell people that the facility is a gun range the size of an aircraft carrier and within the facility are multiple engineering tools, called light gas guns
Evaluating Thermal Control Strategies to Improve Electric Vehicle Range Using GT Suite2026-26-03621/16/2026
This study focuses on enhancing energy efficiency in electric vehicle (EV) thermal management systems through the development and optimization of control logic. A full vehicle thermal management system (VTMS) was modeled using GT-Suite software, incorporating subsystems such as the high voltage battery (HVB), Electric powertrain (EPT), and an 8-zone cabin. Thermal models were validated with experimental data to ensure accurate representation of key dynamics, including coolant to cell heat transfer, cell-to-ambient heat dissipation, and internal heat generation. Control strategies were devised for Active Grille Shutter (AGS) and radiator fan operations, targeting both cabin cooling and EPT thermal regulation. Energy consumption was optimized by balancing aerodynamic drag, fan power, and compressor power across various driving conditions. A novel series cooling logic was also developed to improve HVB thermal management during mild ambient conditions. Simulation results demonstrate
Chothave, Abhijeet, Kumar, Dipesh, Gummadi, Gopakishore, Khan, Parvej, Thiyagarajan, Rajesh, Pandey, Rishabh, S, Ananth, Anugu, Anil, Mulamalla, Sarveshwar, Gangwar, Adarsh
Electroluminescent Coating Systems for Heavy-Duty Trucks: Advancing Safety and Sustainability through Smart Surface Technology2026-26-02751/16/2026
As the transportation industry pivots towards safer and more sustainable mobility solutions, the role of advanced surface technologies is becoming increasingly critical. This paper presents a novel application of electroluminescent (EL) coating systems in heavy-duty trucks, exploring their potential to enhance vehicular safety and reduce environmental impact through lightweight, energy-efficient lighting integration. Electroluminescent coatings, capable of emitting light uniformly across painted surfaces when electrically activated, offer a transformative alternative to conventional external lighting and reflective materials. In the context of heavy-duty trucks, these systems can significantly improve visibility under low-light and adverse weather conditions, thereby reducing the risk of road accidents. Furthermore, the uniform illumination achieved without bulky fixtures contributes to aerodynamic efficiency, supporting fuel economy and reducing carbon emissions. use of this coating
Harel, Samarth Dattatraya, Borse, Manoj, L, Kavya
Predictive Simulation Framework for Tyre Curb Impact Durability Assessment and Design Optimization2026-26-03961/16/2026
With increased deterioration of road conditions worldwide, automotive OEMs face significant challenges in ensuring the durability of structural components. The tyre being the primary point of contact with the road is expected to endure harshest of impacts while maintaining the other performance functions such as Ride & Handling, Rolling resistance, Braking. Thus, it is considered as the most challenging component in terms of design optimization for durability. The current development method relies on physical testing of initial samples, followed by iterative construction changes to meet durability requirements, often giving trade-off in Ride & Handling performance. To overcome these challenges, a frugal simulation-based methodology has been developed for predicting tyre curb impact durability before vehicle-level testing so that corrective action can be taken during the design stage.
Sundaramoorthy, Ragasruoban, Lenka, Visweswara
Qualitative and Quantitative Correlation Study for Exterior Aerodynamics for Automotive Veshicle2026-26-04071/16/2026
Reducing drag forces and minimizing the rear wake region are the main goals of evaluating exterior aerodynamic performance in automobiles. Various literature and experiments shows that the overall fuel computations of the road vehicle improves significantly with the reduction in aerodynamic drag force. In the road vehicle major components of the drag is due the imbalance in pressure between front and rear of the vehicle. At high vehicle speed, aerodynamic drag is responsible for approximately 30 to 40% of the energy consumption of the vehicle. In the recent year, cost of high-performance computing (HPC) has reduced significantly, which helped computational fluid dynamics (CFD) is an affordable tool to the automotive industry for evaluating aerodynamic performance of the vehicle during developing phase. The vehicles aerodynamic performance is greatly impacted by the dynamic environmental conditions it encounters in the real world. Such environmental conditions are difficult to replicate
Chalipat, Sujit, Biswas, Kundan, Tare, Kedar
Drive Cycle Based Energy Audit & Range Estimation for 4X2 Electric Truck2026-26-01631/16/2026
Transportation sector in India accounts for 12% of total energy consumption. Demand of energy consumption is being met by the imported crude oil, which makes transportation sector more vulnerable to fluctuating international crude oil prices. India is mindful of its commitment in 2016 Paris climate agreement to reduce GHG emissions intensity of its GDP by 40% by 2030 as compared to 2005 levels. To fast track the decarbonization of transportation sector, commercial vehicle manufacturers have been exploring other viable options such as battery electric vehicles (BEVs) as a part of their fleet. As on today, BEV has its own challenges such as range anxiety & high total cost of ownership. Range anxiety can be certainly addressed by optimum sizing of electric powertrain, reduction in specific energy consumption (SEC) & use of effective regeneration strategies. Higher SEC can be more effectively addressed by doing vehicle energy audit thereby estimating the energy losses occurring at each
Gijare, Sumant, Karthick, K., Juttu, Simhachalam, Thipse, Sukrut S., A, Jothikumar, J, Frederick Royston, SR, Subasree, G, Harini, M, Senthil Kumar
A Fluid-Structure- Interaction based Methodology to Evaluate Aero-Thermal Performance of Deformable Air Guides2026-26-03641/16/2026
The present work demonstrates a Fluid-Structure Interaction (FSI) based methodology that couples a Finite Volume Method (FVM) and Finite Element Method (FEM) based tools to estimate air guide deformation, thereby predicting accurate aerothermal performance. The method starts with a digital assembly step where the assembly shape and the induced stress due to assembly is predicted. A full vehicle Aerodynamic simulation is performed to extract the surface pressure on the air guide which is then used to estimate the extent of deformation of the air guides. Based on the extent a subsequent Aerodynamic simulation may be carried out to predict thermal efficiency. Comparison against pressure data and deflection data extracted from the wind tunnel experiments of vehicles has shown reasonable match demonstrating the accuracy and usefulness of the method.
Gadasu, Ravishastri, Choudhury, Satyajit, Umesh, Acharya Vaibhav, Kumar, Saravanan, Yenugu, Srinivasa, Zander, Daniel, Beesetti, Siva, Hattarke, Mallikarjun
A High-Fidelity Transient Fluid-Structure-Interaction Methodology for Evaluation of Rear Bumper Flutter of a Vehicle2026-26-04101/16/2026
The present work demonstrates a transient Fluid-Structure-Interaction (FSI) based numerical methodology for estimation of aerodynamic-induced flutter of the rear bumper of a Sports Utility Vehicle (SUV). Finite Volume Method (FVM) based High-fidelity transient full vehicle aerodynamic simulations were conducted for the estimation of the transient aerodynamic load. Subsequently, by mapping this transient aero load onto the surface of the rear bumper, Finite Element Method (FEM) based dynamic structural simulations were performed to predict its response. The results obtained through simulations were then compared against experimental wind tunnel test data of a prototype car with modified bumper for the specific test-case. The pressure and the time series data of rear bumper deflection were captured at multiple probe locations from wind tunnel experiments at 140 and 200 kmph. The distribution of pressure on the rear surfaces of the car was well captured by the aerodynamic simulation at
Choudhury, Satyajit, Yenugu, Srinivasa, Walia, Rajat, Zander, Daniel, Gullapalli, Atchyut, Balan, Arun, Astik, Pritesh
Experimental Study to Investigate and Control Image Blurriness due to IRVM Vibration2026-26-03211/16/2026
Vibration is one of the prominent factors that determine the quality & comfort level of a vehicle. Moreover, if vibration occurs in areas that are almost entirely within customer touchpoints, it could become a critical factor behind vehicle comfort and affects the brand image within the market negatively. The interior rear-view mirror (IRVM) is one of the important components inside passenger cabin, providing drivers with a clear view of the rear traffic. However, vibrations induced by engine operation, road irregularities, and aerodynamic forces can cause the IRVM to oscillate, leading to image blurriness and compromised visibility and safety. This paper investigates the underlying causes of IRVM vibration and its impact on rear visibility. Through experimental analysis we identify key factors contributing to mirror instability. The findings indicate the specific frequencies of vibration, particularly those resonating with the mirror's natural frequency, significantly exacerbating
Khan, Aamir Naved, Saraswat, Vivek, Jha, Kartik, Singh, Hemendra, Seenivasan, Gokulram, Khan, Nafees
Parametric Evaluation of Rolling Resistance in Bias & Radial Tyres and Influence of Key Operational Parameters under Varying Conditions2026-26-06061/16/2026
Tyre rolling resistance is a fundamental parameter in automotive engineering, directly impacting vehicle fuel efficiency and overall performance. The Rolling Resistance Coefficient (RRC) is influenced by tyre construction, material properties, and operational conditions such as inflation pressure, vehicle speed, ambient temperature, and road surface roughness. This study investigates the influence of critical parameters—including test speed, inflation pressure, temperature on the rolling resistance of tyres of various sizes. While previous research has predominantly focused on radial tyres, this paper extends the analysis to include bias-ply tyres. The findings aim to offer valuable insights for policymakers and researchers by examining the behavior of bias tyres under real-world conditions. The results will be particularly beneficial for vehicle and steering system designers, offering data-driven insights to support future tyre and vehicle development. Additionally, the study presents
Joshi, Amol, Belavadi Venkataramaiah, Shamsundara, Khairatkar, Vyankatesh
Use Of Digital Wind Tunnel for Improved Aerodynamic Prediction2026-26-03721/16/2026
In the automotive industry, external aerodynamic evaluations in digital environments are commonly conducted using simplified, large box tunnels with vehicle being static. These approaches are computationally efficient and ensure faster turnaround time. To closely replicate physical wind tunnel testing or real-world conditions, these simulations are often augmented with moving ground and rolling tire configurations. While such setups provide valuable directional feedback for aerodynamic drag improvements, they frequently exhibit significant discrepancies when compared to physical wind tunnel test data. It is observed that key factors such as wind tunnel blockage effects, boundary layer suctions, when not properly accounted for, distort the local flow field dynamics and introduce errors in the simulations. With OEMs aiming to accelerate time-to-market for new vehicle launches, many aspire to minimize reliance on physical testing and maximize use of digital methods for design sign-off
Sharma, Sandeep Kumar, Chalipat, Sujit, Maiyya, Sandeep
The Aerodynamic Development of a Compact SUV for FE Improvement Compliance with CAFE Norms2026-26-05951/16/2026
The Mahindra XUV 3XO is a compact SUV, the first-generation of which was introduced in 2018. This paper explores some of the challenges entailed in developing the subsequent generation of this successful product, maintaining exterior design cues while at the same time improving its aerodynamic efficiency. A development approach is outlined that made use of both CFD simulation and Coastdown testing at MSPT (Mahindra SUV proving track). Drag coefficient improvement of 40 counts (1 count = 0.001 Cd) can be obtained for the best vehicle exterior configuration by paying particular attention to: AGS development to limit the drag due to cooling airflow into the engine compartment Front wheel deflector optimization Mid underbody cover development (beside the LH & RH side skirting) Wheel Rim optimization In this paper we have analyzed the impact of these design changes on the aerodynamic flow field, Pressure plots and consequently drag development over the vehicle length is highlighted. An
Vihan, Nikhil
Exploring the Influence of Wheel Rim Width on Tyre Performance through Rig-Testing and Vehicle-Level Evaluation: A Comprehensive Study2026-26-06031/16/2026
With increasing demand for improving the vehicle Ride and Handling (R&H) performance, the synergy between vehicle subsystems such as suspension, chassis, brakes & tyres play a major role towards it. In this regard, the interaction between wheel rim width and tyre performance characteristics is a key focus area in vehicle development process. Detailed research is being conducted worldwide to understand their dynamics of interaction and based on the tested data, vehicle manufacturers make the design selection. In this context, the proposed study aims to provide a in-depth analysis of how variations in wheel rim width affect key tyre performance parameters such as lateral force characteristics, damping property, tyre footprint, and pinch cut resistance. Also, the subsequent influence on vehicle-level performance parameters such as R&H, braking, steering, and durability is captured. Based on these analysis, appropriate wheel rim size selection is done which is most optimal for the project
Singh, Ram Krishnan, Paua, Ketan, Sundaramoorthy, Ragasruoban, Lenka, Visweswara, ahire, Manoj, Adiga, Ganesh N
Optimization of the Hood Ro-dip CED Process Through Strategic Support Rod Placement at Multiple Locations for Enhanced Hood Gap and Flushness Control in Automotive Manufacturing2026-26-04861/16/2026
The Ro-dip Cathodic Electrodeposition (CED) process is new technology used by automotive manufacturers for higher quality corrosion protection in new generation automobiles. This process involves multiple 360-degree rotation of automotive body-in-white (BIW) which exert higher hydrostatic pressure and drag forces on large surface panels of BIW like hood. For maintaining consistent gaps and flushness control at vehicle level, it is important to safeguard the dimensional stability of light weight (crash performance sensitive) steel hood panel while undergoing through this CED process. This study investigates the enhancement of hood structure supports through strategic optimization of support rod placement and quantity within the Ro-dip CED paint shop system. This Paper underscore the importance of tailored fixture design in the Ro-dip CED process, offering a scalable solution for automotive manufacturers aiming to improve quality while reducing costs associated with dimensional
Tile, Vikrant, Unadkat, Siddharth, Askari, Hasan, Jadhav, Devidas
Comparison of Vortex Identification Methods in Highly Separated Base Wakes15-19-01-00021/10/2026
In this work, the complex wake flow from a double-slanted Ahmed body with an upper slant of α = 25° and a standard single-slanted Ahmed body with a slant angle of 40° were used to evaluate vortex identification methods for automotive wake flows. Multiple three-dimensional (3D) vortex identification methods including Q−, λ 2−, Ω− criteria, and Liutex method and the two-dimensional (2D) Γ1− criterion were evaluated against the streamline topology as a pseudo-truth model. Of the 3D methods analyzed, none were found to produce wholly satisfactory results. The Q− and λ 2−criteria were plagued by high threshold sensitivity and a failure to separate shear from rotation which led to inconsistent identification of the weak, lower-rotation vortices. While the Ω−criterion was able to mitigate the issues related to threshold sensitivity and separation of shear and rotation by consistently identifying the weak vortices, the identified structure did not align well with the streamline topology
Aultman, Matthew, Duan, Lian
Wearables: Controlling Machines on the MoveTBMG-544111/1/2026
Engineers have developed a next-generation wearable system that enables people to control machines using everyday gestures — even while running, riding in a car, or floating on turbulent ocean waves.
Development of a PID Attitude Control System for Sounding Rockets in the International Rocket Engineering Competition2025-36-010512/18/2025
In rocketry competitions, such as the International Rocket Engineering Competition (IREC), unguided sounding rockets are the most commonly used, relying solely on aerodynamic stability to make necessary trajectory corrections during flight. However, this approach has limitations since these vehicles lack mechanisms to ensure apogee accuracy. The active control of a sounding rocket involves methods for orienting and stabilizing the vehicle during flight, using inertial sensors, GPS, and aerodynamic surfaces. These systems allow continuous trajectory and stability adjustments by processing real-time data. In this context, this work proposes the development of a PID-based attitude control system, aligned with IREC guidelines, to improve the accuracy of rocket apogee. For the PID controller design, the second method of the Ziegler-Nichols rule was adopted, based on a linearized transfer function, to calculate the control loop gains. Gain Scheduling technique was employed to estimate gains
Oliveira Junior, Wilson Luiz de, Fazzolari, Heloise Assis, Paiva Carvalho, Carlos Alberto de
Monte Carlo Methods for Evaluating Flight Performance of Sounding Rockets in the International Rocket Engineering Competition2025-36-010612/18/2025
In the launch of sounding rockets, several factors can affect their performance, including uncertainties in aerodynamic design, environmental conditions at the launch site (e.g., wind and temperature), and propulsion-related aspects like the thrust curve and possible deviations. Given these variables, conducting extensive simulations becomes essential to map their influence on the flight. Monte Carlo simulation is a numerical analysis technique that uses random numbers to solve complex problems involving uncertainties and stochastic variables. In rocketry, this method helps analyze the rocket’s flight behavior while accounting for uncertainties in key inputs. In this context, this study presents the Monte Carlo method for simulating university-level sounding rockets, enabling an assessment of the sensitivity of key parameters. To conduct this analysis, five variables were taken into account, including wind, propulsion uncertainties, aerodynamic coefficient uncertainties, and mass
Oliveira Junior, Wilson Luiz de, Fazzolari, Heloise Assis, Paiva Carvalho, Carlos Alberto de
Design Proposals for the Automotive Sector, Case Study2025-36-010812/18/2025
In recent decades, vehicles have evolved from mere means of individual transportation to something much more meaningful. They are no longer mere metal bodies housing combustion engines, but now play a complex role in people’s lives, encompassing emotional, aesthetic, and symbolic aspects. These factors influence consumers’ choice of a model, brand, or version. Based on a literature review of the global automotive sector, including brand literature, scientific articles, and current automotive news, this study aims to analyze the main design and positioning trends adopted by large multinationals in the market. Using the Jeep Renegade as a case study, three design proposals for the model are illustrated and presented as follows: a “facelift,” a “new generation,” and a “concept vehicle.” Next, these design trends are conceptualized, initially illustrating the respective sketches and drafts, which take into account market positioning and the different options for the models presented in
Camilo, Pedro Gomes, Gamarra Rosado, Victor Orlando, Guidi, Erick Siqueira
Aerodynamic Evaluation of the Imperial Front Wing in Higher Ground Clearance2025-36-005712/18/2025
The front wing is a critical component of a Formula 1 car, directly influencing aerodynamic efficiency and overall performance. This study focuses on optimizing the computational simulation process for a Formula 1 front wing, using the Imperial Front Wing (IFW) model as a benchmark. Computational Fluid Dynamics (CFD) simulations were for this study, with a particular emphasis on evaluating ground effect and aerodynamic drag characteristics. A higher ground height configuration of the IFW is evaluated in this study. The results, including aerodynamic coefficients and fluid flow visualizations, were compared with findings from previous literature to assess their accuracy and consistency. The study demonstrated strong alignment with theoretical expectations, validating the simulation approach. Additionally, this research lays the groundwork for further refinements in mesh optimization and simulation methodologies, contributing to more efficient aerodynamic analysis in high-performance
Victor, Gabriel Santos Barreto Freitas, Gonzalez, José Fernando Paz, Alves, Julio César Lelis, Buscariolo, Filipe Fabian
Analysis of the Effect of High-Speed Train Travel on The Characteristics of Flow Field Distribution Near Wrist Arm Insulators in Tunnels2025-99-032712/17/2025
With the continuous progress of modern high-speed railroad technology, the speed of train operation is increasing, and its aerodynamic effect when traversing the tunnel is also getting more and more attention from researchers. In this paper, we constructed a three-dimensional flow field model of the wrist-arm insulator in the tunnel and considered the train speed, tunnel structure, size and position of the wrist-arm insulator, and other factors, and then through the simulation software, we simulated the change of the airflow in the tunnel when the high-speed train enters the tunnel. Through the simulation analysis, we obtained the characteristics of the flow field distribution around the wrist-arm insulator in the tunnel when the high-speed train crosses the tunnel. The results show that when the train crosses the tunnel at a high speed, the airflow inside the tunnel is strongly squeezed and disturbed by the train, forming a complex airflow field. When the train passes by, the wrist
Zhang, Kangkang, Ma, Jianqiao
Fuel Consumption Test Procedure - Type IIJ1321_202512 (Current)12/17/2025
This document describes a rigorous-engineering fuel-consumption test procedure that utilizes industry accepted data collection and statistical analysis methods to determine the change in fuel consumption for trucks and buses with gross vehicle weight rating (GVWR) of more than 10000 pounds, equipped with internal combustion engines using diesel, gasoline, or their liquid substitutes. 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 on-road test procedure is offered as a lower cost alternative to on-track testing, but the user is cautioned that on-road test may result in lower resolution (or precision) data due to a lack of control over the test environment. Test results that do not rigorously follow the method described herein are not intended for public use and dissemination and shall not be represented as an SAE J1321-Type II test result. This document
Truck and Bus Aerodynamics and Fuel Economy Committee
Dynamics Simulation Analysis of a Formula Racing Car with a Novel Rear Wing Based on Carsim2025-99-040312/10/2025
Because regular rear wings on race cars cannot meet all aerodynamic needs, this study tests a new active rear wing on a formula racing car. First, the paper explains the design and key features of the new wing, showing how it helps improve airflow and downforce. Then, the study builds a model of the racing car in Carsim software and adds the new wing to test its performance. After that, simulations compare the new wing to traditional ones, focusing on speed, grip, and handling. The results prove that the new wing makes the car faster and more stable in corners. This means the active rear wing is a better solution than fixed wings, and it could be useful for future race car designs.
Yu, Wanbo
Items per page:
1 – 50 of 7112