Browse Topic: Aerodynamics

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"Parametric Evaluation of Rolling Resistance in Bias & Radial Tyres and influence of key operational parameters under varying conditions."2026-26-0606To be published on 01/16/2026
Tyre rolling resistance is a fundamental parameter in automotive engineering, directly impacting vehicle fuel efficiency and overall performance. The Rolling Resistance Coefficient (CRR) is influenced by tyre construction, material properties, and operational conditions such as inflation pressure, vehicle speed, load, ambient temperature, and road surface roughness. This study investigates the influence of critical parameters—including test speed, inflation pressure, load, temperature, and slip angle—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, which remain widely used in ASEAN countries, including India. The findings aim to offer valuable insights for policymakers and researchers by examining the behaviour of bias tyres under real-world conditions. Special focus is given to the influence of slip and camber angles, with experiments conducted on passenger
Joshi, Amol, Khairatkar, Vyankatesh, Belavadi Venkataramaiah, Shamsundara
Use Of Digital Wind Tunnel For Improved Aerodynamic Prediction2026-26-0372To be published on 01/16/2026
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 times. 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
A High-Fidelity Transient Fluid-Structure-Interaction Methodology for Evaluation of Rear Bumper Flutter of a Vehicle2026-26-0410To be published on 01/16/2026
The need for fuel efficient and pedestrian safe cars leads to the use of thinner and lighter car exteriors. Interaction of these exterior car components at high speed with an aerodynamic load can lead to undesirable aero-elastic vibration and flutter. Early identification and mitigation of such vibration can bring significant cost and time benefit, by reducing dependence on prototype testing and recalibration of prototype tooling at later stages. The present work demonstrates a transient Fluid-Structure-Interaction based numerical methodology for estimation of aerodynamic-induced flutter of the rear bumper of an SUV. The proposed method performs coupled-high fidelity transient full vehicle aerodynamic Finite Volume based and dynamic rear bumper structural Finite Element based simulations required for flutter estimation. The method has been put through a two-step validation against experimental wind tunnel test data of a prototype car with modified bumper for the specific test-case. The
CHOUDHURY, SATYAJIT, Yenugu, Srinivasa, Walia, Rajat, Zander, Daniel, Gullapalli, Atchyut, BALAN, ARUN, Astik, Pritesh
Exploring the Influence of Wheel Rim Width on Tire Performance through rig testing and Vehicle-level Evaluation: A Comprehensive study2026-26-0603To be published on 01/16/2026
With increasing challenges for optimizing vehicle ride and handling performance along with efficiency, the synergy between major systems such as suspension, chassis, brakes & tires has been investigated in the past. In this regard, the interaction between wheel rim width and tire performance characteristics has become a topic of interest. Extensive research is being conducted in the automotive industry to understand their key interaction dynamics and make appropriate design selections. This study aims to provide a comprehensive analysis of how variations in wheel rim width affect key tire performance parameters such as lateral force characteristics ,damping property, tire footprint, and pinch cut resistance. Also, the subsequent influence on vehicle-level performance parameters such as braking, ride & handling, steering, and durability is captured. Through rig level testing and full-vehicle evaluation data, several key observations have emerged. Firstly, it was observed that narrower
Singh, Ram Krishnan, Paua, Ketan, Sundaramoorthy, Ragasruoban, LENKA., VISWESWARA, ahire, Manoj, Adiga, Ganesh N
Experimental Study to Investigate and Control Image Blurriness due to IRVM Vibration2026-26-0321To be published on 01/16/2026
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 (during either city or highway driving conditions), it could become a critical factor behind the deterioration of brand image within the market. 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 vibrations and their impact on image clarity. Through a combination of experimental analysis and computational modelling, we identify key factors contributing to mirror instability. The findings indicate the specific frequencies of vibration, particularly those
Khan, Aamir Naved, Saraswat, Vivek, Jha, Kartik, SINGH, HEMENDRA, Seenivasan, Gokulram, Khan, Nafees
The Aerodynamic development of a Compact SUV for FE improvement and compliance with CAFE norms2026-26-0595To be published on 01/16/2026
The Mahindra 3XO is a compact SUV, the first-generation was introduced by Mahindra in 2018. This paper explores some of the challenges entailed in developing the next 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 • Front wheel deflector optimization • Mid underbody cover development (beside the LH & RH side skirting) • Wheel Rim optimization • Rear wake control strategy In this paper we have analysed 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
Qualitative and Quantitative Correlation Study for Exterior Aerodynamics for Automotive Vehicle2026-26-0407To be published on 01/16/2026
The objective of the exterior aerodynamic performance assessment of automotive vehicles is to reduce the aerodynamic drag pressure and rear side wake zone, which improves overall energy consumption of the vehicle. Almost 30 to 40% of the energy is required to overcome the drag force and wake zone pressure offered by the air on the automotive vehicle. With the increase in high performance computing power (HPC) and its affordability, computational fluid dynamics (CFD) has become a popular and more effective tool for aerodynamic design and analysis in the automobile industry. In the real-world scenario, automotive vehicle is subjected to varying wind and operating conditions which affect its aerodynamic characteristics, and therefore it is difficult to reproduce such physical phenomenon in a conventional wind tunnel. Hence, the entire aerodynamic assessment was done in wind tunnel which is equipped with advanced aerodynamic assessment techniques like wheel rotations, boundary layer
Chalipat, Sujit, Biswas, Kundan, Tare, Kedar
Evaluating Thermal Control Strategies to Improve Electric Vehicle Range Using GT Suite2026-26-0362To be published on 01/16/2026
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 sub-systems such as the high-voltage battery (HVB), e-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 e-powertrain 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
Drive Cycle Based Energy Audit & Range Estimation for 4X2 Electric Truck2026-26-0163To be published on 01/16/2026
Transportation sector in India accounts for 18% 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 by 35% 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 powertrain component of
Gijare, Sumant, Karthick, K., Juttu, Simhachalam, Thipse, Sukrut S., A, Jothikumar, J, Frederick Royston, SR, Subasree, G, Harini, M, Senthil Kumar
Cooling Flow Measurement TechniquesJ2082_202511 (Current)11/21/2025
This SAE Information Report has been prepared at the request of the SAE Road Vehicle Aerodynamics Forum Committee (RVAC), incorporating material from earlier revisions of the document first prepared by the Standards Committee on Cooling Flow Measurement (CFM).Although a great deal is already known about engine cooling, recent concern with fuel conservation has resulted in generally smaller air intakes whose shape and location are dictated primarily by low vehicle drag/high forward speed requirements. The new vehicle intake configurations make it more difficult to achieve adequate cooling under all conditions. They cause cooling flow velocity profiles to become distorted and underhood temperatures to be excessively high. Such problems make it necessary to achieve much better accuracy in measuring cooling flows.As the following descriptions show, each company or institution concerned with this problem has invested a lot of time and as a result gained considerable experience in developing
Road Vehicle Aerodynamics Forum Committee
EDITORIAL: Farewell and thanks, Mr. Birch21AUTP06_0401/27/2025
“We pay close attention to the SAE magazines because your guy in Europe writes interesting articles,” a BMW engineering executive told me one year at the Frankfurt Motor Show. He was referring to Stuart Birch, our veteran European Editor, who has recently decided - after nearly 37 years of outstanding reporting for SAE International - to hang up his keyboard and spend more time with his wife, Kim, their family and friends in the British countryside, and his classic Porsche 911. Our staff had been dreading the day that Stuart would announce his retirement, foremost because he's been a great friend as well as a colleague. And because journalists with his qualities - professionalism, perspective, a powerful work ethic and great wit - are increasingly rare in the mobility-technology space. As SAE's global audience knew, Stuart Birch delivered compelling technical and business information. He covered product, processes and people with equal poise. And he thrived on the R&D beat: Virtual
Brooke, Lindsay
AI-Trained Vehicles Can Adjust to Extreme Turbulence on the FlyTBMG-5212512/01/2024
In nature, flying animals sense coming changes in their surroundings, including the onset of sudden turbulence, and quickly adjust to stay safe. Engineers who design aircraft would like to give their vehicles the same ability to predict incoming disturbances and respond appropriately. Indeed, disasters such as the fatal Singapore Airlines flight this past May in which more than 100 passengers were injured after the plane encountered severe turbulence, could be avoided if aircraft had such automatic sensing and prediction capabilities combined with mechanisms to stabilize the vehicle.
GPS-BASED MOBILITY POWER ANALYSIS OF MILITARY VEHICLES2024-01-331111/15/2024
ABSTRACT Determining the required power for the tractive elements of off-road vehicles has always been a critical aspect of the design process for military vehicles. In recent years, military vehicles have been equipped with hybrid, diesel-electric drives to improve stealth capabilities. The electric motors that power the wheel or tracks require an accurate estimation of the power and duty cycle for a vehicle during certain operating conditions. To meet this demand, a GPS-based mobility power model was developed to predict the duty cycle and energy requirements of off-road vehicles. The dynamic vehicle parameters needed to estimate the forces developed during locomotion are determined from the GPS data, and these forces include the following: the gravitational, acceleration, motion resistance, aerodynamic drag, and drawbar forces. Initial application of the mobility power concept began when three U.S. military’s Stryker vehicles were equipped with GPS receivers while conducting a
Ayers, Paul, Bozdech, George
Quantification of the Aerodynamic Interference for Counter-Rotating Coaxial Rotors In-Ground EffectF-0080-2024-000405/07/2024
The performance of a coaxial rotor hovering in-ground effect (IGE) is compared against the out-of-ground effect (OGE) condition to quantify the rotor-ground interaction and against an isolated rotor IGE at equivalent blade loading to quantify the rotor-rotor interaction. It is observed that the performance of the coaxial rotor improves when it hovers IGE. However, the rotor-rotor and rotor-ground interactions compete, which affects the performance of the coaxial rotor. This paper aims to quantitatively measure the aerodynamic interactions of the CCR in IGE by developing a theoretical framework based on momentum theory. This formulation introduced induced power factors to understand the aerodynamic interactions of a CCR operating IGE. The performance measurements show that the rotor-ground interaction in the CCR system behaved similarly to a single rotor operating in IGE conditions. The interactional effects significantly influence the individual rotors as the rotor-rotor interactions
Moore, Zachary, Silwal, Lokesh, Vijayaraj, Aditya, Raghav, Vrishank
Qualitative and Quantitative Correlation Study for Exterior Aerodynamics for Automotive Vehicle2024-26-026201/16/2024
The main objective of the external aerodynamic performance assessment of automotive vehicles is to reduce the aerodynamic drag, which improves overall energy consumption of the vehicle. Almost 40% of the energy is required to overcome the drag force offered by the air on the automotive vehicle. With the increase in high performance computing power (HPC) and its affordability, computational fluid dynamics (CFD) has become a popular and more effective tool for aerodynamic design and analysis in the automobile industry. In the real-world scenario, automotive vehicle is subjected to varying wind and operating conditions which affect its aerodynamic characteristics, and therefore it is difficult to reproduce such physical phenomenon in a conventional wind tunnel. Hence, the entire aerodynamic assessment was done in S2A wind tunnel which is equipped with advanced aerodynamic assessment techniques like wheel rotations, boundary layer suction, moving ground etc. The current work mainly focuses
Biswas, Kundan, Tare, Kedar, Chalipat, Sujit
High Speed Driveline Power Loss & Influencing Factors2024-26-033701/16/2024
Energy savings in automotive applications has always remain an important aspect of research. In addition, today's highspeed requirements in electric vehicles require high-efficiency drivelines to match overall vehicle mileage or range. This paper presents the validation of the overall efficiency & drag losses of the highspeed Driveline for an ATV with 4 Wheel Drive System. The efficiency & drag losses were measured in the powertrain testbed where the test units were placed between two Transient Dynamometers. The main aim of the test was to validate the overall efficiency as a function of input speed and torque. All these measured values of the gearbox efficiency are included in various graphs. The tests were performed for complete functional range of UUT at max. operating oil temperatures for Transmission and Front Differential testing. Drive shafts tests were performed at its complete range and various inclination angle up to max. failure point. The Wheel Hub was tested at various
Jain, Sankalp, Singh, Parminder
Advanced Thermal Management System for Electric Vehicles – An Indian Case study2024-26-012601/16/2024
Climate change and global warming is one of the major challenges faced by the world today. A significant number of Indian cities rank among the most polluted globally, with vehicular emissions being a primary contributor. To address this issue, Government of India is actively advocating for the adoption of zero-emission vehicles, such as electric vehicles, through policies and initiatives like FAME II, PMP, and the National Mission for Transformative Mobility and Storage. The acceptance of electric vehicles is growing in the Indian market seeing more than 200 % increased sales with large shares of 2-wheelers, 3-wheelers & compact cars getting electrified. One of the major inhibitors to EV sales being the high overall electric vehicle cost compared to conventional vehicles with HV battery is the most costly system on the present day electric vehicles . An electric vehicle having high energy efficiency can meet it's driving range requirements with a relatively smaller battery size
Emran, Ashraf, Chavan, Sagar, Franke, Kai, Sharma, Vijay, Garg, Shivam, Pawar, Bhushan, Hemkemeyer, David
Topological Optimization of Non-Pneumatic Unique Puncture-Proof Tire System Spoke Design for Tire Performance15-17-01-0001-TEST-REC07/18/2023
Abstract Non-pneumatic tires (NPTs) have been widely used due to their advantages of no occurrence of puncture-related problems, no need of air maintenance, low rolling resistance, and improvement of passenger comfort due to its better shock absorption. It has a variety of applications as in earthmovers, planetary rover, stair-climbing vehicles, and the like. Recently, the unique puncture-proof tire system (UPTIS) NPT has been introduced for passenger vehicles segment. The spoke design of NPT-UPTIS has a significant effect on the overall working performance of tire. Optimized tire performance is a crucial factor for consumers and original equipment manufacturers (OEMs). Hence to optimize the spoke design of NPT-UPTIS spoke, the top and bottom curve of spoke profile have been described in the form of analytical equations. A generative design concept has been introduced to create around 50,000 spoke profiles. Finite element model (FEM) model is developed to evaluate the stiffness and
Dhrangdhariya, Priyankkumar, Maiti, Soumyadipta, Rai, Beena
NOISE ANALYSIS IN DIFFERENT FLAPPING MECHANISMS FOR EFFICIENT FLYING2025-01-002105/05/2023
In a variety of intricate and dynamic settings, flying animals, like birds and insects [5],[8], can fly with efficiency. Despite being stated as "unsteady aerodynamics", the flapping of birds was the first biological mechanism that inspired humans to fly. Though flapping wings is the most efficient way of flying, the main hindrance is its unsteady nature of gaining a counter-lift for each flap. Compared to current manned aerial vehicles, flying animals fly at a lower Reynolds number. A fluid's ratio of viscous to inertial forces is represented by the Reynolds number, which is a dimensionless quantity. The ratio of forward speed to flapping frequency is represented by the dimensionless number known as the decreased frequency. Yet, by utilizing these beneficial animal flying traits, unmanned aerial vehicles (UAVs) functioning in the low Reynolds number zone can be enhanced. The primary aim of this project is to analyze two flapping mechanisms: straight continuous wing and swept & bent
Keshav Kumar, A B, Patric, Alan, R, Asad Ahmed, Srinivasan, Venkatramanan, Mani, Midhun, Jayachandran, Rohith
Identification and Analysis of Aerodynamic Sound Sources on the External Surface of an SUV2025-01-003305/05/2023
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-rearview mirror-front side
zhang, hao
Experimental Investigation into Modulated Aeroacoustic Cabin Noise arising from Unsteady Flow Conditions2025-01-002905/05/2023
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 the use of experimental approach using an SUV-shaped vehicle to assess the effect of unsteady wind on the modulated noise performance, commonly used to evaluate unsteady wind noise characteristics. 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, to provide insight into the noise generation mechanisms and differences in behaviour between the two environments. The vehicle response to unsteady wind conditions was assessed using two approaches: a dynamic upstream unsteady flow the using active side wind
Jamaluddin, Nur Syafiqah, Oettle, Nicholas, Staron, Domenic
An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications - QA Test Tatsiana01-17-01-000104/19/2023
Abstract In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfully at a system level by evaluating their range and endurance, but cannot do so at an aerodynamic level when using lift and drag coefficients, CL and CD , as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes an aerodynamic equation of state for lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hovering Ingenuity Mars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10 Bronco. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects. Part III applies the aerodynamic equation of state to some well-trodden cases in fluid
Burgers, Phillip
An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications - QA Test Tatsiana01-17-01-0001-TEST-REC04/19/2023
Abstract In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfully at a system level by evaluating their range and endurance, but cannot do so at an aerodynamic level when using lift and drag coefficients, CL and CD , as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes an aerodynamic equation of state for lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hovering Ingenuity Mars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10 Bronco. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects. Part III applies the aerodynamic equation of state to some well-trodden cases in fluid
Burgers, Phillip
An Aerodynamic Equation of State—Part III: Applications to Fluid Statics and Dynamics01-17-01-000304/19/2023
The aerodynamic equation of state is introduced in Part I and applies to selected aerospace systems. Part II applies it to the flapping of hovering and forward-flying biological fliers. This last Part III expands the aerodynamic equation of state by adding the potential energy term, assumed up to this point to be zero as the system and its trajectory is placed coplanar with an arbitrary reference potential plane. Part III applies the expanded equation of state to familiar and well-trodden fluid-static and fluid-dynamic cases selected from fluid mechanic textbooks.
Burgers, Phillip
An Aerodynamic Equation of State—Part II: Applications to Flapping Flight01-17-01-000204/19/2023
Part I introduced the aerodynamic equation of state. This Part II introduces the aerodynamic equation of state for lift and induced drag of flapping wings and applies it to a hovering and forward-flying bumblebee and a mosquito. Two- and three-dimensional graphical representations of the state space are introduced and explored for engineered subsonic flyers, biological fliers, and sports balls.
Burgers, Phillip
An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications01-17-01-000104/19/2023
In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfullyby evaluating their range and endurance, but cannot do so atwhen using lift and drag coefficients,and, as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes anfor lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hoveringMars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects. Part III applies the aerodynamic equation of state to some well-trodden cases in fluid mechanics found in fluid-mechanics textbooks.
Burgers, Phillip
Aerodynamic Drag of Road Vehicles in Close Lateral Proximity2023-01-095204/11/2023
Aerodynamic interaction between vehicles on a roadway can modify the fuel use and greenhouse gas emissions of the vehicle relative to their performance under isolated, uniform-wind conditions. A comprehensive wind-tunnel study was undertaken to examine changes to the aerodynamic drag experienced by vehicles in close proximity, in adjacent lanes. Wind-load measurements were conducted for two general configurations: 15%-scale testing with light-duty-vehicle (LDV) models, and 6.7%-scale testing with a heavy-duty vehicle (HDV) model. For the LDV study, a DrivAer model was tested with a proximate AeroSUV model or an Ahmed model at lateral distances representing 75%, 100%, and 125% of a typical highway lane spacing, and for longitudinal distances up to 2 vehicle lengths forward and back. Commensurate measurements were conducted for the AeroSUV model with the proximate DrivAer or Ahmed model. For the HDV study, a tractor-trailer model was tested with a single or combination of adjacent-lane
McAuliffe, Brian, Barber, Hali
Aerodynamics of Landing Maneuvering of an Unmanned Aerial Vehicle in Close Proximity to a Ground Vehicle2023-01-011804/11/2023
Autonomous takeoff and landing maneuvers of an unmanned aerial vehicle (UAV) from/on a moving ground vehicle (GV) have been an area of active research for the past several years. For military missions requiring repeated flight operations of the UAV, precise landing ability is important for autonomous docking into a recharging station, since such stations are often mounted on a ground vehicle. The development of precise and efficient control algorithms for this autonomous maneuvering has two key challenges; one is related to flight aerodynamics and the other is related to a precise detection of the landing zone. The aerodynamic challenges include understanding the complex interaction of the flows over the UAV and GV, potential ground effects at the proximity of the landing surface, and the impact of the variations in the surrounding wind flow and ambient conditions. While a large body of work in this area can be found on the control aspect of the UAV landing and takeoff maneuvers
Uddin, Mesbah, Nichols, Spencer, Hahn, Cortney, Misar, Adit, Desai, Shishir, Tison, Nathan, Korivi, Vamshi
Aerodynamic Investigation by Computational Fluid Dynamics to Exterior Design Modifications in a Simplified Bus Model2023-01-5003-TEST-REC01/04/2023
Abstract Exterior design modifications have crucial importance on vehicle aerodynamics. Therefore, it makes one of the key parameters to achieve to reduce the fuel consumption in diesel-, CNG-, and hybrid-powered engines and increase the range of electric vehicles (EVs). The slightest change in the vehicle exterior design can directly affect the vehicle aerodynamics. Thus, four different parameters (front windshield angle, front diffuser angle, rear diffuser angle, and fillet [bending] on the rear and front top) are reviewed on a conceptual 12 m long bus which is to be designed at Anadolu Isuzu. Computational fluid dynamics (CFD) simulations become a source for comparative evaluations in these studies. Simulations are carried out for all different models with a realizable k-epsilon turbulence model and enhanced wall treatment wall function. In conclusion, a positive aerodynamic effect is observed with parameters that are the windshield, front diffuser angle, and fillet on the rear and
Özcan, Onur, Yıldız, Alp Eren
Aerodynamic Investigation by Computational Fluid Dynamics to Exterior Design Modifications in a Simplified Bus Model2023-01-500301/04/2023
Abstract Exterior design modifications have crucial importance on vehicle aerodynamics. Therefore, it makes one of the key parameters to achieve to reduce the fuel consumption in diesel-, CNG-, and hybrid-powered engines and increase the range of electric vehicles (EVs). The slightest change in the vehicle exterior design can directly affect the vehicle aerodynamics. Thus, four different parameters (front windshield angle, front diffuser angle, rear diffuser angle, and fillet [bending] on the rear and front top) are reviewed on a conceptual 12 m long bus which is to be designed at Anadolu Isuzu. Computational fluid dynamics (CFD) simulations become a source for comparative evaluations in these studies. Simulations are carried out for all different models with a realizable k-epsilon turbulence model and enhanced wall treatment wall function. In conclusion, a positive aerodynamic effect is observed with parameters that are the windshield, front diffuser angle, and fillet on the rear and
Özcan, Onur, Yıldız, Alp Eren
Aerodynamic Investigation by Computational Fluid Dynamics to Exterior Design Modifications in a Simplified Bus Model2023-19-500301/04/2023
Exterior design modifications have crucial importance on vehicle aerodynamics. Therefore, it makes one of the key parameters to achieve to reduce the fuel consumption in diesel-, CNG-, and hybrid-powered engines and increase the range of electric vehicles (EVs). The slightest change in the vehicle exterior design can directly affect the vehicle aerodynamics. Thus, four different parameters (front windshield angle, front diffuser angle, rear diffuser angle, and fillet [bending] on the rear and front top) are reviewed on a conceptual 12 m long bus which is to be designed at Anadolu Isuzu. Computational fluid dynamics (CFD) simulations become a source for comparative evaluations in these studies. Simulations are carried out for all different models with a realizable k-epsilon turbulence model and enhanced wall treatment wall function. In conclusion, a positive aerodynamic effect is observed with parameters that are the windshield, front diffuser angle, and fillet on the rear and front top
Özcan, Onur, Yıldız, Alp Eren
Automation of Aviation Weather Charts using Machine Learning Techniques2022-26-123105/26/2022
In traditional avionics procedures, manual analysis of aviation weather charts is often time consuming and increases the pilot's workload significantly. This manual analysis plays a key role in identifying the weather phenomena, which an airborne weather radar cannot detect such as Clear Air turbulence (CAT). The paper proposes introduction of Machine Learning (ML) algorithms to decode the pictorial representation of Significant Meteorological Information (SIGMETS), and significant weather charts during take-off procedures and textual representation of METER and TAF during in-flight later on. During take-off procedures, ML algorithms are provided with the flight path for the aircraft under consideration, which is about to fly, SIGMET, 14 different routes of aircraft which are about to fly and significant weather charts. CAT on a significant weather chart, turbulence is highlighted by the area surrounded by dashed lines. Area of possible CAT due to close proximity of isotachs can be
Gangadhar, Balraj, Ramasamy, Subramanian
Numerical Drag and Lift Predictions of Transport Aircrafts2022-26-118605/26/2022
Accurate estimation of drag and lift during take-off/landing and flight of an aircraft is critical in improving its performance. The flow separation and aerodynamic forces estimation using a CFD simulation are very sensitive to numerical methods, types of grid, turbulence models and other numerical treatments. In this paper, results from the simulations of two aircraft models using a RANS based CFD software, SimericsMP+ are presented. One set of simulations are performed on a DLR-F6 model at conditions of 0.75 Mach number and 3.0e6 Reynolds number as provided in the 2nd AIAA CFD Drag Prediction Workshop. The flow behavior over a range of angle of attack during the flight condition at transonic speed is simulated for Wing Body Nacelle Pylon (WBNP) configuration of DLR-F6 model. The second set of simulations are performed on JAXA high-lift configuration Standard Model (JSM) with nacelle-off configuration. These simulations are performed for high-lift conditions of 0.172 Mach number and
Godavarthi, Raghu Vamsee, Wang, Junfeng, Maiti, Dipak
An Effective Design of Micro Tesla Valve as a Passive Mixer in Microfluidics Channels 2022-26-117805/26/2022
Mixing fluids is one of the major challenges in microfluidics. Normally, the mixing process is done by diffusion rather than turbulence, which makes it very slow due to low Reynolds number (Re) flow in the range of 0.1 to1. Owing to this behaviour, ineffective mixing occurs when two miscible liquids are mixed purely by diffusion which requires longer striation lengths and therefore longer microfluidic channels along with lengthy mixing time. Homogeneous mixing of solute and solvent is important for providing consistent chemical and biological reactions in µTAS.In this study, we develop a passive mixer that provides efficient mixing using micro tesla valves which allows the flow of liquids in the forward and reverse directions to analyse the formed vortices, turbulent intense areas, Reynolds number, and pressure using Ansys fluent workbench. An optimum design has been arrived by varying the number of cells from 1 to 5 in series and realization is done by excimer laser micromachining.
Singh, Deepak, Sankar PhD, Ravi
Design and Parametric Investigations on Various Propellers for Nature Inspired Unmanned Amphibious Vehicle2022-26-117405/26/2022
Unmanned Amphibious Vehicle (UAV) is an integrative working environments based vehicle, which doesn’t allocate the place for onboard pilots. Mostly, unmanned amphibians have been controlled through pre-provided algorithms in the predestined paths. Aerodynamic and hydrodynamic working conditions are the compositions of aforesaid integrative environments, wherein the possible lifespan affecting failure of UAV may chance to happen in a high manner. Thus, the multidisciplinary investigation on UAV and it's every component needs to be done in order to pick the suitable UAV parts for both missions executing conditions. This work deals the comprehensive computational investigations on a different number of blades equipped propellers for the proposed cum nature-inspired UAV under aerodynamic and hydrodynamic loading conditions. Three different propellers are uniquely constructed based on the aerodynamic environment reference with the guidance of analytical formulae and thereafter modeling
R, Vijayanandh, Mathaiyan, Vijayakumar, Raji, Arul Prakash, Madasamy, Senthil Kumar, Gnanasekaran, Raj Kumar
The Short-flight Alternative22AVEP04_0804/01/2022
The Budget Airline Car is an EV alt-shuttle seating six adults, with luggage storage in each door. Short-haul airline flights can be a great convenience for travelers, but they produce more CO2 emissions - about 250 g/km per person - than any other form of passenger transportation, including compact EVs and electric trains. That's about 25% more emissions than long-haul flights, because short-hop flying uses proportionately more fuel at takeoff and landing. Could an automotive alternative offer a solution? That is what Car Design Research (CDR), a U.K.-based consultancy, set out to investigate, working with design associates Yichen Shu in China and Aditya Jangid in India. The resulting concept is the Budget Airline Car, one of six new passenger-vehicle types that CDR director Sam Livingston and his team feel would be enabled by new mobility technologies.
Kendall, John
An Estimation of the Effect of Turbulence from the Natural Wind and Traffic on the Cycle-Averaged-Drag Coefficient. 2022-01-107603/29/2022
A drag coefficient, which is representative of the drag of a car undergoing a particular drive cycle, known as the cycle-averaged-drag coefficient, has been previously developed. It was derived for different drive cycles using mean values for the natural wind. It assumed terrain dependent wind velocities based on the Weibull function, equi-probable wind direction and shear effects. It did not, however, include any effects of turbulence in the natural wind. Some recent research using active vanes in the wind tunnel to generate turbulence has suggested that the effect on drag can be evaluated from the quasi steady wind inputs. On this basis the effect of natural wind turbulence on the aerodynamic drag of a typical car has been obtained as a function of car velocity and both wind velocity and direction. For a particular combination of car and wind velocity the additional effects of turbulence are very sensitive to the wind angle and on the shape of the drag curve with yaw angle. The wind
Howell, Jeff, Passmore, Martin
Transient car aerodynamics during an overtaking maneuver: a wind-tunnel flow simulation study2022-01-107503/29/2022
An overtaking process realized in a wind tunnel, implying a BMW car model passing a correspondingly designed truck model (with both vehicles being down-scaled according to 1:2.5), has been investigated computationally by applying the PANS (Partially-averaged Navier-Stokes) approach representing a scale-resolving hybrid RANS/LES (Reynolds-averaged Navier-Stokes / Large-eddy Simulation) model (Basara et al.; AIAA Journal 42(12), 2011). A complementary study including the flow past an isolated BMW car model has been preliminary performed. The characteristic car-relevant flow Reynolds number, based on the axis-center distance and air velocity (of 140 km/h) corresponds to 3 million. The present overtaking maneuver, referred to as a “quasi-stationary” sequence, has been realized by considering eight distinct positions the car model takes relative to the truck configuration. Accordingly, a complete overtaking event accounting for the car positions corresponding to the car approaching the
Kutej, Lukas, Basara, Branislav, Tropea, Cameron, Hussong, Jeanette, Jakirlic, Suad
An Investigation of Aerodynamic Characteristics of Three Bluff Bodies in Close Longitudinal Proximity – Part 3: Influence on Lift2022-01-107103/29/2022
The aerodynamic effects of bodies in close proximity continues to be an interest for those involved in aeronautical, automotive and civil engineering together with those involved in sports such as cycling, motor racing and sailing. For passenger cars, research in the USA published in the 1980s had considered travelling in close proximity, termed “platooning”, as a means for reducing congestion. But the aerodynamic drag reduction and fuel-savings found in associated wind tunnel tests and road-trials became the focus of further investigations. Although practical applications were not originally pursued, the recent development of control systems for connected and autonomous vehicles has provided the opportunity for platooning to be considered again within future traffic management systems. Thus while the focus of automotive work to date has been the potential for the reduction in total aerodynamic drag, the associated changes in aerodynamic lift which might influence the characteristics
Le Good, Geoffrey, Self, Matthew, Boardman, Peter, Resnick, Max, Cirstea, Remus
On-road Aerodynamic Measurement Techniques2022-01-109603/29/2022
The development of car shape to provide optimal aerodynamic behaviour is typically an iterative process involving test and development. Two main test and development methods are used: wind tunnel testing (of both models and full-size cars) and Computational Fluid Dynamic (CFD) modelling. However, especially for development teams working on a small budget, there are problems with both approaches. Wind tunnel testing of full-size cars is extremely expensive. In addition, access may be problematic, especially for longer periods of testing. To be accurate, wind tunnel testing of models requires a high degree of model fidelity and appropriate wind tunnel conditions to avoid adverse Reynolds Number effects. CFD modelling, while very valuable, varies widely in quality and is always proved through physical testing. Another approach, covered in this paper, is to carry out aerodynamic testing on the road. For example, car aerodynamic drag is normally reduced if areas of separated flow along the
Edgar, Julian
An Investigation of Aerodynamic Characteristics of Two Bluff Bodies in Close Longitudinal Proximity – Sensitivity to Front-End Geometry2022-01-109203/29/2022
With an increasing focus on the reduction of greenhouse gases by transport industries and the continued development of connected and autonomous vehicle systems, the potential for aerodynamic drag reduction by means of managed systems of vehicles travelling in close-proximity, termed “platooning”, has continued as topic for research. For commercial vehicles the principle variable for drag reduction has been the inter-vehicle spacing since, in effect, the constituents of platoons are of similar geometry. Early-work in passenger car platooning was also conducted with homogeneous platoons, but more recently the use of systematic changes in upper-body geometry has provided a further variable in the assessment of platooning characteristics. The work shown in this paper adds to investigations illustrated in SAE Papers 2019-01-0659 and 2021-01-0952 using the Windsor model with interchangeable backlight angle geometry. For this investigation a new add-on geometry to the nose was introduced to
MacAskill, James, Le Good, Geoffrey, Cirstea, Remus
The Effect of Unsteady Incident Flow on Drag Measurements for Different Vehicle Geometries in an Open Jet Wind Tunnel2022-01-109003/29/2022
Automotive engineers use the wind tunnel to improve a vehicle’s aerodynamic properties on the road. However, a car driving on the road does not experience the steady-state, uniform flow characteristic of the wind tunnel. Wind, terrain and traffic all cause the flow experienced by the vehicle to be highly transient. Therefore, it is imperative to understand the effects of unsteady flow on the forces the vehicle experiences. To this end, the FKFS swing® installed in the University of Stuttgart’s model scale wind tunnel was used to create 36 different incident flow signals with time-resolved yaw angles. The cD values of five different 25% vehicle models, each with a notchback and a squareback configuration, were measured while under the influence of the aforementioned signals. The vehicle models were chosen to ensure a variety of different geometries, but at the same time also to enable isolated comparison of specific geometric properties. All drag measurements were corrected using the
Fei, Xiao, Kuthada, Timo, Wagner, Andreas, Wiedemann, Jochen
Study and Analysis of External Drag Reduction Methods for Tractor-Trailer Trucks using 3D CFD2022-01-109303/29/2022
Heavy vehicles play a huge role in the national economy of a country and are responsible for the transportation of a major portion of goods across the terrain. In the United States alone, over 85% of the total value of goods are transported with the help of heavy vehicles. Despite the heavy reliance, these vehicles are not fuel-efficient and more than 40% of the engine’s power production is utilized in overcoming the vehicle aerodynamic drag at highway speeds. The present work explores drag reduction methods that could be used as an external aid for cargo trailer trucks. The paper focuses on 3D CFD analysis of different boat-tail designs that could be used to reduce aerodynamic drag on trailers. The boat tails analysed has been optimised in coherence with standard legal norms for European and US highways. It has been found and established that a truncated boat tail works as a better drag reduction measure than a full or completely inflated boat tail. The commercial code of Simerics MP
Varshney, Anchal, Khandagale, Vitthal, Saha, Rohit
New Metrics for Quantifying the Energy Efficiency of Platoons in the Presence of Disturbances2022-01-064503/29/2022
Due to aerodynamic drag reduction, vehicles have shown significant fuel savings while platooning in close succession. However, when circumstances force active deceleration to maintain the platoon, such as vehicle cut-ins or grade changes, the aerodynamic efficiency benefits may be undermined. In this work, the influence of active deceleration on platooning dynamics is investigated using over 400 hours of experimental data from PID-controlled and NMPC-controlled vehicle platoons. The test vehicles are Class 8 line-haul tractors with dry vans and various powertrain configurations. Using J1939 CAN data and GPS-estimated grade profiles, off-throttle data is isolated and longitudinal acceleration is estimated as a function of grade using Kalman filtering. Efficiency losses are analyzed as a function of active deceleration and analyzed to describe the effects of grade and cut-ins on platooning fuel economy. Finally, new metrics are proposed to analyze the efficiency of platoons that
Stegner, Evan, Snitzer, Philip, Bevly, David M., Hoffman, Mark
The Proper Orthogonal and Dynamic Mode Decomposition of wake behind a Fastback DrivAer Model2022-01-108603/29/2022
The aerodynamic design optimization of a ground vehicle highly depends on the wake region behind it. Vehicle's wake and its instability have a major contribution to the drag, lift, and side forces experienced by the vehicle. In this paper, we investigate numerically the dynamic characteristics of wake downstream of a realistic generic car model, DrivAer, at a Reynolds number Re=4.87E06. Two methods, Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) are applied to symmetric and asymmetric 2D planes at y=0 and 0.5 H to decompose the unsteady wake to its major dynamic modes. We simulated the flow field using the turbulence model URANS/IDDES then applied POD and DMD on streamwise and spanwise velocity components and the pressure fields. Wake dynamic mode analysis enables us to capture different modes and their contributions to the kinetic energy distribution within the region of interest. For DrivAer geometry, at high Reynolds number, we observed quasi-steady wake
Ahani, Hamed, Uddin, Mesbah, Nielsen, Jonas
Aerodynamic drag and downforce of a sport motorcycle 2022-01-107303/29/2022
The aerodynamic drag and lift of a sport-motorcycle was investigated in a full-scale and in a 1/6th scale wind tunnel tests. The results show the large vertical load transfer to the rear wheel as vehicle’s speed increases. Consequently, several simple dive and splitter-plates were tested to increase the aerodynamic downforce. These devices were added at a relatively low position on the bodywork in order to avoid adverse handling effects while leaning in turns. This study shows the level of downforce that can be generated by simple add-ons without major alterations to the bodywork. Consequently, for higher levels of aerodynamic downforce, larger underbody surfaces or wings are needed.
Katz, Joseph
Effect of Aero Covers on Underfloor Wind Noise; Conclusions from a Wind Tunnel Validated, Aero-Vibro-Acoustic Model 2022-01-036703/29/2022
Low frequency interior wind noise is typically dominated by underfloor flow noise. The source mechanisms are fluctuating surface pressure loading from both turbulence and acoustic field levels developed in the semi-reverberant cavity between floor and road. Previous studies have used computation fluid dynamics (CFD) to estimate the aero-acoustic loading applied to a vibro-acoustic model, which is then used to predict the transmitted interior wind noise. This paper reports a new perspective in two respects. First it uses sophisticated surface pressure microphone arrays to directly measure the underfloor aero-acoustic loading in the wind tunnel. Second, it considers two different underfloor aerodynamic configurations – with and without lightweight aero cover panels, which are installed primarily to reduce aerodynamic drag. Results are presented showing the relative contributions of turbulence versus acoustic sources and demonstrating validation of the aero-vibro-acoustic model for
Terakado, Susumu, Bremner, Paul
Design Optimization of Bicycle Wheel Hub Assembly for Automotive Applications2022-01-030503/29/2022
The diminutive rolling resistance and wheel bearing drag characteristics of a bicycle wheel assembly makes it a lucrative choice of component in numerous 3-wheeled (3W) and 4-wheeled (4W) automotive applications. However, when a bicycle wheel is subjected to the loads encountered in such applications, complications pertaining to strength, durability and, performance are encountered. Since a bicycle wheel is intended to be arrested at either end of its axle, cantilever loading of the component as practiced in automotive applications diminishes the ability of the spindle to withstand longitudinal, and vertical forces encountered. Furthermore, while cornering on a bicycle, the maneuver of leaning in a corner significantly reduces the lateral stiffness requirement of the hub flanges. Therefore generic hub assemblies are designed without accounting for the action of lateral forces that are experienced at the hub with the wheel held vertical. Since most bicycle wheel assemblies are designed
Chakraborty, Apurva, R, Shreyas, Kanhai, Palash
Aerodynamic study of the different spoiler section design used in formula-SAE cars2021-28-018110/01/2021
Aerodynamics of a car plays a very important role in a racing car. That is why many race cars are designed to take advantage of aerodynamics. Improvement cornering speed in the race car is achieved through increase in the downforce on the tire. Spoilers (inverted wings) are used for increasing the downforce but this increases the drag too. The performance of a racing car depends on both the downforce and drag, requiring good compromise between these two forces. In this paper, different airfoils which are used for building front and rear spoiler of the race car are analyzed. NACA 0012 is analyzed at 0° angle of attack the front spoiler design is made on the basis of the result with the analysis of S1223 (s1223-il) and GOE304 at 10° and 17° . Modeling of a wing is has been done in Solid work and CFD analysis using ANSYS software. Keywords: Aerodynamics, ANSYS, CFD analysis, Front and rear wing, spoiler.
Patil, Shrikant, Bhaskara Rao, Lokavarapu
Influence of Tyre Rolling Resistance and Operational Parameters on Vehicle Fuel Efficiency2021-26-050309/22/2021
There has been a persistent demand for Vehicle fuel efficiency improvement, mainly due to ever-increasing fuel price and imposition of stricter regulatory norms to curb greenhouse gas emissions. Factors like driving style, vehicle weight, engine, tyre, aerodynamics, weather conditions, etc. affect fuel efficiency. This study focuses on the impact of certain sub-parameters like tyre construction, tyre wear, inflation pressure and driver behavior to establish a correlation between the Rolling Resistance Coefficient (RRC) of a tyre and the fuel efficiency of the vehicle. Tyres with contrasting RRC are considered with multiple drivers and driving conditions while measuring Fuel efficiency using test cycles defined as Constant Speed Test (CST), Mixed Cycle Test (MCT) and Public Road Test (PRT). Fuel consumption sensitivity to driving behavior or driving aggressiveness varies even within expert drivers [1][2]. Reduction in Non-Skid Depth due to tyre wear adversely affects its properties
TOMER, AVINASH, Chepyala, Shiva Kumar Reddy, Mukhopadhyay, Rabindra, Ghosh, Prasenjit
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