Browse Topic: Aerodynamics

Items (7,102)
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, AmolBelavadi Venkataramaiah, ShamsundaraKhairatkar, Vyankatesh
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 NavedSaraswat, VivekJha, KartikSingh, HemendraSeenivasan, GokulramKhan, Nafees
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 DattatrayaBorse, ManojL, Kavya
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, SatyajitYenugu, SrinivasaWalia, RajatZander, DanielGullapalli, AtchyutBalan, ArunAstik, Pritesh
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 KumarChalipat, SujitMaiyya, Sandeep
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, VikrantUnadkat, SiddharthAskari, HasanJadhav, Devidas
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
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 KrishnanPaua, KetanSundaramoorthy, RagasruobanLenka, Visweswaraahire, ManojAdiga, Ganesh N
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, SujitBiswas, KundanTare, Kedar
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, AbhijeetKumar, DipeshGummadi, GopakishoreKhan, ParvejThiyagarajan, RajeshPandey, RishabhS, AnanthAnugu, AnilMulamalla, SarveshwarGangwar, Adarsh
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, RagasruobanLenka, Visweswara
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, SumantKarthick, K.Juttu, SimhachalamThipse, Sukrut S.A, JothikumarJ, Frederick RoystonSR, SubasreeG, HariniM, Senthil Kumar
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, MatthewDuan, Lian
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.
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 deFazzolari, Heloise AssisPaiva Carvalho, Carlos Alberto de
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 FreitasGonzalez, José Fernando PazAlves, Julio César LelisBuscariolo, Filipe Fabian
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 deFazzolari, Heloise AssisPaiva Carvalho, Carlos Alberto de
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 GomesGamarra Rosado, Victor OrlandoGuidi, Erick Siqueira
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
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, KangkangMa, Jianqiao
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
This study focuses on the multifunctional three-body high-speed unmanned boat model, and experimentally measures the roll attenuation characteristics under different draft conditions. It focuses on the influence of the initial roll angle on roll attenuation, and analyzes the change pattern of roll angle over time. Experimental results show that the model shows obvious self-oscillation period and amplitude attenuation. Based on the system identification theory and combined with improved genetic algorithms, a mathematical model used to simulate the roll attenuation motion of the boat model was constructed. The difference between experimental data and fitted values was further evaluated using identification software and verified with data at specific roll angles. In addition, the study also deeply analyzed the change trend of the roll moment coefficient with the initial roll angle. By comparing the experimental results of the three-mall boat and the catamaran, it was found that the three
Zhang, DiTong, WeiYu, QingzhuLiu, Bofei
Off-highway vehicles (OHVs) routinely navigate unstable and varied terrains—mud, sand, loose gravel, or uneven rock beds—causing increased rolling resistance, reduced traction, and high energy expenditure. Traditional rigid chassis systems lack the flexibility to adapt dynamically to changing surface conditions, leading to inefficiencies in vehicle stability, maneuverability, and fuel economy. This paper proposes an adaptive terrain morphing chassis (ATMC) that can actively modify its structural geometry in real-time using embedded sensors, hydraulic actuators, and soft robotic elements. Drawing inspiration from nature and recent advances in adaptive materials, the ATMC adjusts vehicle ground clearance, track width, and load distribution in response to terrain profile data, thereby optimizing fuel efficiency and performance. Key contributions include: A multi-sensor fusion system for real-time terrain classification Hydraulic actuators and morphing polymers for variable chassis
Vashisht, Shruti
Ammonia, a carbon-neutral fuel, is a promising candidate for next-generation engine applications. However, its low flame speed (~7cm/s) and prolonged ignition delay (~10ms at stoichiometric conditions) impose significant challenges in achieving stable and efficient combustion across varying operating conditions. At high-speeds, incomplete combustion due to limited residence time reduces efficiency, while at low-speeds, ignition instability and low combustion temperatures hinder reliable operation. To address these challenges, the Passive Turbulent Jet Ignition (PTJI) system has been proposed to enhance turbulence-driven mixing and improve ignition characteristics. This study focuses on optimizing a PTJI system for ammonia-fueled engines using a three-phase methodology. First, the 800cc 2-cylinder gasoline engine was modified for ammonia using numerical analysis, and a baseline analysis of the combustion characteristics was conducted. Next, a turbulent intensity study within the PTJI
Ju, KangminKang, Hyun-UngKim, Jeong Hyeon
Real Driving Emission (RDE) testing for motorcycles presents unique challenges due to the motorcycle’s lightweight construction, limited mounting space, and sensitivity to added mass and aerodynamic drag. Full-functional automotive Portable Emission Measurement Systems (PEMS), while highly accurate, are often impractical for two-wheelers as their weight and size can alter driving resistances, fuel consumption, and emission profiles, but also complicate installation and probably effect the drivability of the vehicle. To address these limitations, lightweight alternatives such as Mini-PEMS and ultralightweight alternatives such as Sensor-based Emission Measurement Systems (SEMS) offer compact, low-power solutions tailored for small vehicles. SEMS are typically equipped with lower cost sensors and low-tech gas conditioning systems compared to PEMS. Due to this these systems may not meet regulatory homologation requirements. Nevertheless, they provide justifiable accuracy for many real
Schurl, SebastianLienerth, PeterJaps, LeonidSchroeder, MatthiasSchmidt, StephanKirchberger, Roland
India, being one of the largest automotive markets has considered various policies affecting fuel efficiency to curb vehicle carbon emissions. In a typical light-duty vehicle (LDV), around 20% of the fuel's energy is used to power the wheels and overcome aerodynamic drag resistance. Aerodynamic drag resistance, influenced by the projected surface area, cooling drag and velocity refers to the resistive force encountered by the vehicle. Furthermore, cooling drag resistance is determined by the effective cooling system architecture and aerodynamic design of the front-end module (FEM), which has major impact on the vehicle's performance and ram curve. In the pursuit of enhancing cooling system architecture, this paper investigates thermal performance and structural integrity of using common fins for both the condenser and radiator to improve the inlet aerodynamic performance which lowers cooling fan power consumption. Preliminary results show a 12% notable reduction in motor power
K, MuthukrishnanVijayaraj, Jayanth MuraliN, AswinNarashimagounder, ThailappanMahobia, Tanmay
To address the growing concern of increasing noise levels in urban areas, modern automotive vehicles need improved engineering solutions. The need for automotive vehicles to have a low acoustic signature is further emphasized by local regulatory requirements, such as the EU's regulation 540/2014, which sets sound level limits for commercial vehicles at 82 dB(A). Moreover, external noise can propagate inside the cabin, reducing the overall comfort of the driver, which can have adverse impact on the driving behavior, making it imperative to mitigate the high noise levels. This study explores the phenomenon of change in acoustic behavior of external tonal noise with minor geometrical changes to the A-pillar turning vane (APTV), identified as the source for the tonal noise generation. An incompressible transient approach with one way coupled Acoustics Wave solver was evaluated, for both the baseline and variant geometries. Comparison of CFD results between baseline and variant showed
Pawar, SourabhSharma, ShantanuSingh, Ramanand
TOC
Tobolski, Sue
Recent experimental work from the authors’ laboratory demonstrated that applying a boosted current ignition strategy under intensified flow conditions can significantly reduce combustion duration in a rapid compression machine (RCM). However, that study relied on spark anemometry, which provided only localized flow speed estimates and lacked full spatial resolution of velocity and turbulence near the spark gap. Additionally, the influence of turbulence on combustion behavior and performance across varying flow speeds and excess air ratios using a conventional transistor-controlled ignition (TCI) system was not thoroughly analyzed. In this study, non-reactive CFD simulations were used to estimate local flow and turbulent velocities near the spark gap for piston speeds ranging from 1.2 to 9.7 m/s. Simulated local velocities ranged from 0.7 to 96 m/s and were used to interpret experimentally observed combustion behavior under three excess air ratios (λ = 1.0, 1.4, and 1.6). Combustion was
Haider, Muhammad.ShaheerJin, LongYu, XiaoReader, GrahamZheng, Ming
System-level design decisions in Formula SAE (FSAE) vehicles drive all downstream subsystem designs, yet these decisions are often based on historical precedent or anecdotal evidence rather than rigorous analysis. This work presents a simulation-driven methodology to support data-informed decisions early in the design process, specifically examining how overall vehicle parameters—such as engine power, vehicle mass, aerodynamic drag and lift, wheelbase, and track width—influence performance in a representative FSAE endurance scenario. Two types of lap-time simulation tools were used in this study: OpenLAP, a point-mass simulator, and ChassisSim, a transient 3D vehicle dynamics simulator that incorporates suspension geometry, yaw response, weight transfer, and steering effects. Initial simulations with OpenLAP were used to rapidly identify trends and guide early design decisions, while ChassisSim was used for detailed sensitivity analyses and to validate system-level trade-offs in a more
Hernandez, Andy JoseBachman, John Christopher
This terminology document is intended to provide a common nomenclature for use in publishing road vehicle aerodynamics data and reports.
Road Vehicle Aerodynamics Forum Committee
Electro-mechanical braking (EMB) system has emerged as a potential candidate that serves the brake-by-wire technology. Several mechanisms are used to transmit the clamp force, where each has efficiency losses due to static friction and viscous damping. Compensating these losses is essential for accurate responses such that meeting the performance goal and improving the stopping distance of the EMB. Mathematical and empirical models are used to estimate these losses so that clamp force is accurately estimated and controlled. However, none of these models are capable of addressing the part-to-part variation or predicting the impact of other noise factors on these losses such as operating temperature and degradation. The purpose of this work is to online estimate the EMB coulomb friction by introducing an external torque command over a period of time while observing the system’s response. This approach continuously measures the coulomb friction while the system is in normal operation
Aljoaba, SharifRamakrishnan, RajaDobbs, Jeremy
Electric vehicles (EVs) require improved drag performance from wheel bearings to achieve a longer range. EVs are heavier and have higher torque output compared to internal combustion-powered vehicles. Due to the increased weight and torque of EVs, there will be higher loads at the bearing-to-knuckle joint. These increased loads may necessitate higher clamp loads to maintain joint integrity. However, higher clamp loads can lead to distortion or reduced roundness of the wheel bearing outer ring. Such distortion permanently increases drag and reduces bearing life. Therefore, after vehicle corner assembly with higher clamp loads, it is critical to minimize outer ring distortion during the initial assembly and throughout the bearing's lifespan. This paper will cover the design considerations for the wheel bearing outer ring to minimize distortion, utilizing Computer-Aided Engineering (CAE) analysis for various designs. A Design of Experiments (DOE) will be conducted to understand the
Mandhadi, Chaitanya ReddyCallaghan, KevinSutherlin, RobertLee, SeungpyoLee, YeonsikBovee, Benjamin
As automotive manufacturers have tried to set themselves apart by reducing emissions, and increasing vehicle range/fuel economy by eliminating any energy loss from inefficiencies on the vehicle, the brake corners have been an area of interest to reduce off-brake torque to zero in all conditions. Caliper designers can revise some attributes like piston seal grooves, and pad retraction features to reduce drag, but even if a caliper is designed perfectly in all aspects, trying to measure it in a reliable and repeatable manner proves to be difficult. There are many ways to measure brake drag all with ranging complexity. Some of the simplest measurements are the most repeatable, but it excludes the majority of the vehicle inputs. The most vehicle representative testing requires the most complex equipment and comes with the most challenges. This paper will focus mainly on the different ways residual brake drag can be measured, the benefits and challenges to each of them, the problems trying
Retting, Joshua
In the present article it is investigated why active grille shutters (AGS) can have very different aerodynamic characteristics, ranging from progressive to strongly degressive, and which factors influence them. For this purpose, the authority concept known from the field of heating, ventilation, and air-conditioning (HVAC) is referred to. According to this theory, the control characteristics of dampers depend primarily on the ratio of the pressure losses at the fully open damper to the pressure losses of the rest of the system. The adaptation of the concept to the automotive field shows that, in addition to the pressure losses, the geometry of the cooling air ducting plays a decisive role in motor vehicles. The effect of driving speed and fan operation on the characteristic curves is also being investigated. In addition, authority theory can also be used to derive the conditions under which the opening characteristic curve of an AGS provides a good prediction of the real characteristic
Wolf, Thomas
For further elucidation of the extremely complex mechanism of wall heat transfer during diesel flame impingement, heat flux measurement results based on two different relatively new approaches, high-speed infrared thermography and Micro Electro- Mechanical Systems (MEMS) heat flux sensor, were compared. Both measurements were conducted on the chamber wall impinged by a diesel flame achieved in constant volume combustion vessels under similar experimental conditions. Infrared thermography was conducted using a high-speed infrared camera (TELOPS M3k, 13,000 fps, 128×128 pixels), allowing the capture of time-series temperature and heat flux distributions on the wall surface with a spatial resolution of 70 μm (9 mm / 128 pixels). This high-resolution imaging also enables detailed estimation of near-wall turbulent structures, which are considered to significantly influence the heat flux distributions. The MEMS sensor is composed of closely aligned (520 microns separated) multiple highly
Shimizu, FumikaMorooka, MasatoAizawa, TetsuyaDejima, KazuhitoNakabeppu, Osamu
The transportation and mobility industry trend toward electrification is rapidly evolving and in this specific scenario, wind noise aeroacoustics becomes one of the major concerns for OEMs, as new propulsion systems are notably quieter than traditional ones. There is, however, very limited references available in the literature regarding validation of computational fluid dynamics (CFD) simulations applied to the prediction of aeroacoustics contribution to the noise generated by large commercial trucks. Thus, in this work, high-fidelity CFD simulations are performed using lattice Boltzmann method (LBM), which uses very large eddy simulation (VLES) turbulence model and compared to on-road physical tests of a heavy-duty truck to validate the approach. Furthermore, the effect of realistic wind conditions is also analyzed. Two different truck configurations are considered: one with side mirror (Case A) and the other without (Case B) side mirrors. The main focus of this work is to assess the
Guleria, AbhishekNovacek, JustinIhi, RafaelFougere, NicolasDasarathan, Devaraj
The recent advancements in vehicle powertrain and aerodynamics have led to an increase in the production of faster passenger cars, where high-speed driving scenarios demand equally efficient and safe braking systems to ensure the safety of both passengers and surrounding vehicles and pedestrians. At high speeds, aerodynamics can significantly impact overall vehicle braking performance due to the interaction between downforces and lift forces, which, in turn, affects the vehicle’s overall dynamic weight, directly contributing to the maximum attainable deceleration or braking force. Accordingly, the braking performance can be maximized by generating more downforce by means of rear spoilers, while taking into consideration their inevitable drag, which adds to the total vehicle motion resistance. Therefore, this proposed work aims to investigate the effectiveness of employing an active rear spoiler to enhance the vehicle’s braking performance, without introducing remarkable drag that could
Abidou, DiaaAbdellah, Ahmed HelmyHaggag, Salem
Electric Vertical Take-Off and Landing (eVTOL) aircraft, conceptualized to be used as air taxis for transporting cargo or passengers, are generally lighter in weight than jet-fueled aircraft, and fly at lower altitudes than commercial aircraft. These differences render them more susceptible to turbulence, leading to the possibility of instabilities such as Dutch-roll oscillations. In traditional fixed-wing aircraft, active mechanisms used to suppress oscillations include control surfaces such as flaps, ailerons, tabs, and rudders, but eVTOL aircraft do not have the control surfaces necessary for suppressing Dutch-roll oscillations.
In this article the transition of a laminar boundary layer (BL) over a flat plate is characterized using an acoustic technique with a pitot probe linked to a microphone unit. The probe was traversed along a BL plate at a fixed wind tunnel flow velocity of 5.5 m/s. A spectral analysis of the acoustic fluctuations showed that this setup can estimate the streamwise location and length of the BL transition region, as well as the BL thickness, by using the intermittency similitude approach. Further work is required to quantify the uncertainty caused by signal attenuation within the data acquisition system.
Lawson, Nicholas JohnZachos, Pavlos K.
In recent years, there has been a significant rise in research focused on estimating the base pressure (Pb) characteristics of convergent–divergent nozzles with sudden expansion regions. This study explores the use of geometrical parameters as a control strategy for nozzles experiencing abrupt expansion at supersonic Mach numbers within an axisymmetric duct. It focuses on four distinct novel expansion duct configurations: square nozzle (SN), step square nozzle (SSN), curved nozzle (CN), and double curved nozzle (DCN). In this work, the high-speed compressible flow investigation is carried out numerically using control volume method on the nozzle with a fixed area ratio (AR) and L/D nozzle. Standard k-ε turbulence model is used in the analysis to access the recirculation region formed near the nozzle walls. The recirculation zone directly influences the Pb and shock cell. For NPR range from 2 to 10, SSN and CN shows an increase in Pb, which further increases the thrust and decreases the
Raj, R. JiniKumar, P. DeepakPanchksharayya, D. V.Kousik Kumaar, R.Praveen, N.
The present study aims to simulate the non-reacting flow within the cylinder of a two-stroke spark ignition internal combustion engine (SIE) utilizing gasoline direct injection (GDI). A computational fluid dynamics (CFD) analysis was employed to forecast the turbulence levels of the in-cylinder flow, including the root-mean-square (RMS) turbulent velocity. The three-dimensional model was developed using ANSYS-FLUENT. The investigation examined the intake manifold inclination angles of 0°, 10°, 20°, 30°, and 40° for two different types of single-intake port engines (I and II) and a single-type double-intake port engines, that are presented at an engine speed of 1500 rpm. The findings revealed that the highest RMS turbulent velocities occurred at a 30° inclination for the double-intake engine, while the single-intake engines (I) and (II) showed peak velocities at 0° and 10°, respectively. Furthermore, in single-intake engine (I), the RMS turbulent velocity was found to be 38.7% greater
Soliman, MohabElbadawy, Ibrahim
The unsteady wind conditions experienced by a vehicle whilst driving on the road are different to those typically experienced in the steady-flow wind tunnel development environment, due to turbulence in the natural wind, moving through the unsteady wakes of other road vehicles and travelling through the stationary wakes generated by roadside obstacles. This paper presents an experimental approach using a large SUV-shaped vehicle to assess the effect of unsteady wind on the modulated noise performance, commonly used to evaluate unsteady wind noise characteristics. The contribution from different geometric modifications were also assessed. The approach is extended to assess the pressure distribution on the front side glass of the vehicle, caused by the aerodynamic interactions of the turbulent inflow in straight and yawed positions, to provide insight into the noise generation mechanisms and differences in behaviour between the two environments. The vehicle response to unsteady wind
Jamaluddin, Nur SyafiqahOettle, NicholasStaron, Domenic
Currently, effective methods for analyzing the aerodynamic sound sources of Sport Utility Vehicles (SUVs) are still under development, and the relationship between sound sources and flow dynamics is not yet fully understood. This study presents a method for identifying multi-frequency sound dipole sources within the near-wall flow field by analyzing the relationship between unsteady flow field properties and dipole sources, thereby addressing the complex characteristics of aerodynamic sound sources on vehicle surfaces. Wind tunnel tests, along with full-scale (1:1) Large Eddy Simulation (LES) were conducted on a real SUV. The identification method was applied to analyze the location and magnitude of sound sources near the vehicle's surface. The results, validated using Acoustic Perturbation Equations (APE), indicated that the dipole sources are primarily distributed around the windward side of the front wheels, the side of the front headlights, the A pillar-side mirror-front side
Zhang, HaoJia, QingWang, Yigang
This paper presents a fully parallelized Computational Acoustics (CA) module, integrated within the Simerics-MP+ platform, developed for the prediction of noise source power and far-field propagation across a range of Computational Fluid Dynamics (CFD) applications. Utilizing the Ffowcs Williams-Hawkings (FWH) acoustic analogy, the CA module seamlessly integrates with existing CFD workflows, offering minimal computational overhead with less than a 5% increase in runtime. Extensive validation has been conducted against analytical, numerical, and experimental data in various acoustic scenarios, including monopole and dipole noise emissions, flow around slender bodies, circular cylinders and aero-propellers. These validation studies underscore the reliability of the framework in accurately identifying noise sources and assessing the impact of design modifications, significantly reducing the need for expensive physical prototyping in industries such as automotive and aerospace. Building
Taghizadeh, SalarCzwielong, FelixBecker, StefanVarghese, JoelRaj, GowthamDhar, Sujan
This study evaluates the effectiveness of two hybrid computational aeroacoustic methods—Lighthill wave model and perturbed convective wave model—in simulating HVAC duct noise in the automotive industry. Using component-level acoustic testing of a Ford HVAC duct, simulations were conducted at varying airflow rates to assess the accuracy of both models in predicting duct noise. The Lighthill wave model, suitable for noise analysis in regions outside turbulent flow areas, showed a good correlation with experimental data, especially in the frequency range of 100 Hz–5000 Hz, but sometimes struggled with pseudo-noise effects at low frequencies near turbulent regions. The perturbed convective wave model, which is suitable for noise analysis anywhere in the flow domain, underpredicted sound pressure levels at low frequencies as well. Both models underpredicted high-frequency noise (>5 kHz) due to insufficient mesh and time-step sizes. Despite these limitations, the Lighthill wave model
Nam, Jee-WhanMendel, MarcGolberg, Igor
Multiple-ion-probe method consists of multiple ion probes placed on the combustion chamber wall, where each individual ion probe detects flame contact and records the time of contact. From the recorded data, it is also possible to indirectly visualize the inside of the combustion chamber, for example, as a motion animation of moving flame front. In this study, a thirty-two ion probes were used to record flames propagating in a two-stroke gasoline engine. The experiment recorded the combustion state in the engine for about 3 seconds under full load at about 6500 rpm, and about 300 cycles were recorded in one experiment. Twelve experiments were conducted under the same experimental conditions, and a total of 4,164 cycles of signal data were obtained in the twelve experiments. Two types of analysis were performed on this data: statistical analysis and machine learning analysis using a linear regression model. Statistical analysis calculated the average flame detection time and standard
Yatsufusa, TomoakiOkahira, TakehiroNagashige, Kohei
New regulations introduced by the Fédération Internationale de l’Automobile (FIA) for the 2026 Formula 1 season mark the first instance of active flow control methods being endorsed in Formula 1 competition. While active methods have demonstrated significant success in airfoil development, their broader application to grounded vehicle aerodynamics remains unexplored. This research investigates the effectiveness of trapped vortex cavity (TVC) technology in both active and passive flow controls, applied to a NACA0012 airfoil and an inverted three-element airfoil from a Formula 1 model. The investigation is conducted using numerical methods to evaluate the aerodynamic performance and potential of TVC in this paper. In the single-airfoil case, a circular cavity is placed along the trailing edge (TE) on the suction surface; for the three-element airfoils, the cavity is positioned on each airfoil to determine the optimum location. The results show that the presence of a cavity, particularly
Ng, Ming KinTeschner, Tom-Robin
Automotive signal processing is dealt with in several contributions that propose various techniques to make the most out of the available data, typically for enhancing safety, comfort, or performance. Specifically, the accurate estimation of tire–road interaction forces is of high interest in the automotive world. A few years ago the T.R.I.C.K. tool was developed, featuring a vehicle model processing experimental data, collected through various vehicle sensors, to compute several relevant virtual telemetry channels, including interaction forces and slip indices. Following years of further development in collaboration with motorsport companies, this article presents T.R.I.C.K. 2.0, a thoroughly renewed version of the tool. Besides a number of important improvements of the original tool, including, e.g., the effect of the limited slip differential, T.R.I.C.K. 2.0 features the ability to exploit advanced sensors typically used in motorsport, including laser sensors, potentiometers, and
Napolitano Dell’Annunziata, GuidoFarroni, FlavioTimpone, FrancescoLenzo, Basilio
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