Download or read book Important Factors for Accurate Scale Resolving Simulations of Automotive Aerodynamics written by Petter Ekman and published by Linköping University Electronic Press. This book was released on 2020-04-02 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Road transports are responsible for almost 18 % of the greenhouse gas emission in Europe and are today the leading cause of air pollution in cities. Aerodynamic resistance has a significant effect on fuel consumption and hence the emission of vehicles. For electric vehicles, emissions are not affected by the aerodynamics as such but instead have a significant effect on the effective range of the vehicle. In 2017, a new measurement procedure was introduced, Worldwide Harmonized Light Vehicles Test Procedure (WLTP), for measuring emissions, fuel consumption, and range. This procedure includes a new test cycle with increased average driving speed compared to the former procedure, which thereby increases the importance of the aerodynamic resistance, as it drastically increases with speed. A second effect is that the exact car configuration sold to the customer needs to be certified in terms of fuel consumption and emissions. The result is that every possible combination of optional extras, which might affect the aerodynamic resistance, needs to be aerodynamically analyzed and possibly improved. From 2021, the European Commission will introduce stricter emission regulations for new passenger cars, with the fleet-wide average lowered to 95 grams CO2=km, which puts an even higher demand on achieving efficient aerodynamics. Virtual development of the aerodynamics of road vehicles is today used to a great extent, using Computational Fluid Dynamics, as it enables faster and cheaper development. However, achieving high accuracy for the prediction of the flow field and aerodynamic forces is challenging, especially given the complexity of both the vehicle geometry in itself and the surrounding flow field. Even for a simplified generic bluff body, accurately predicting the flow field and aerodynamic forces is a challenge. The main reason for this challenge of achieving results with high accuracy is the prediction of the complex behavior of turbulence. Scale-resolving simulation (SRS) methods, such as Large Eddy Simulation (LES), where most of the turbulent structures are resolved has in many studies shown high accuracy but unfortunately to a very high computational cost. It is primarily the small turbulent structures within the near-wall region that requires a _ne resolution in both space (the mesh) and in time. This fine resolution is the reason for the very high computational cost and makes LES unfeasible for practical use in industrial aerodynamic development at present and in the near future. By modeling the turbulent structures within the near-wall region using a Reynolds-Averaged Navier-Stokes (RANS) model, and resolving the turbulence outside the region with a LES model, a coarser resolution is possible to use, resulting in significantly lower computational cost. Which used RANS model is of high importance, and especially how much turbulent viscosity the model generates, as too high values can result in suppression of the resolved turbulence. The transitioning between the RANS and LES regions have a significant effect on the results. Faster transition enables more resolved turbulence, favorable for higher accuracy, but needs to be balanced with sufficient shielding of the RANS region. If resolving the turbulence occurs within the near-wall region, and the mesh is not sufficiently fine, it can result in poor accuracy. By increasing the time-step size and disregarding best-practice guides, the computational cost can be significantly reduced. The accuracy is reasonably insensitive to the larger time step sizes until a certain degree, thereby enabling computationally cheaper SRS to achieve high accuracy of aerodynamic predictions needed to meet present and future emission regulations.
Download or read book Aerodynamics of Road Vehicles written by Thomas Christian Schuetz and published by SAE International. This book was released on 2015-12-30 with total page 1312 pages. Available in PDF, EPUB and Kindle. Book excerpt: The detailed presentation of fundamental aerodynamics principles that influence and improve vehicle design have made Aerodynamics of Road Vehicles the engineer’s “source” for information. This fifth edition features updated and expanded information beyond that which was presented in previous releases. Completely new content covers lateral stability, safety and comfort, wind noise, high performance vehicles, helmets, engine cooling, and computational fluid dynamics. A proven, successful engineering design approach is presented that includes: • Fundamentals of fluid mechanics related to vehicle aerodynamics • Essential experimental results that are the ground rules of fluid mechanics • Design strategies for individual experimental results • General design solutions from combined experimental results The aerodynamics of passenger cars, commercial vehicles, motorcycles, sports cars, and race cars is dealt with in detail, inclusive of systems, testing techniques, measuring and numerical aerodynamics methods and simulations that significantly contribute to vehicle development. Aerodynamics of Road Vehicles is an excellent reference tool and an indispensable source for the industry’s vehicle engineers, designers, and researchers, as well as for enthusiasts, students, and those working in academia or government regulatory agencies.
Download or read book A Comprehensive Study of Detached Eddy Simulation written by Charles Mockett and published by Univerlagtuberlin. This book was released on 2009 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vehicle Aerodynamics written by V. Sumantran and published by . This book was released on 1996 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection of 38 SAE papers offers a window into the significant advancements that have been made over the last decade in the field of vehicle aerodynamics. Topics covered include wind-tunnel testing, on-road testing, computational simulations, thermal analysis, and acoustics. Selected examples of aerodynamic development in the design process of a vehicle are presented. This valuable resource illustrates the progress automakers have made in continually improving the level of aerodynamic efficiency of cars and trucks produced throughout the world. Sections cover: Historical Background/Overview; Wind Tunnel Testing; On-Road Testing; Computational Fluid Dynamics; Vehicle Aerodynamic Development and Drag Reduction; Aerodynamics of Engine Cooling; and Vehicle Aerodynamics and Aeroacoustics.
Download or read book Progress in Vehicle Aerodynamics and Thermal Management written by Jochen Wiedemann and published by Springer. This book was released on 2017-12-04 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: The books presents latest information about new car developments, new or improved testing techniques and new or improved calculation procedures. Presenters are from industry and academia.
Download or read book A Second Generation URANS Approach for Application to Aerodynamic Design and Optimization in the Automotive Industry written by Liangyu Xu (Ph.D.) and published by . This book was released on 2020 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the U.S., transportation is responsible for approximately 70% of all petroleum consumption and is now the largest source of carbon emissions and air pollution. Aerodynamics is an important aspect for energy saving and emission reduction in the automotive industry. In the design stage, aerodynamic drag is minimized through optimization of the vehicle shape, and Computational Fluid Dynamics (CFD) has become an invaluable tool to support this process. In combination with advanced optimization methods, CFD promises to considerably reduce the carbon footprint of modern passenger and good transportation. However, its success is severely limited by the poor description of complex unsteady turbulence at a practicable computational cost. For the flow past a car, unsteady turbulent flow structures are generated in the separation off the windshield, the mirrors, the wheels, and in the wake of the car body. Capturing these turbulent structures is important for an accurate evaluation of the aerodynamic drag, especially for trains and freight trucks, where flow interaction between multiple bodies is involved and influences the overall drag. While high fidelity CFD techniques like Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) offer the ability to resolve the necessary turbulent structures and therefore predicting the drag with high accuracy, their computational costs are high that cannot allow efficient optimization. Reynolds Averaged Navier-Stokes (RANS) approach is most widely used for its computationally effectiveness and robustness, but current RANS models have turned out to have a poor description of complex unsteady turbulence. Hybrid models offer a potential balance between accuracy and computational cost. Despite increased accuracy, the present hybrid models suffer from lack of robustness, grid consistency, ease of use. To address the issues of the existing hybrid models and to better address the industrial need for a robust, grid consistent, and widely applicable hybrid model, an interesting new approach has been proposed by Lenci [1] and Baglietto [2], which aims at increasing locally resolving the flow structures in the framework of second-generation URANS approach (2G-URANS), and is named STRUCT. The idea has shown the potential to provide improved accuracy, robustness, and mesh consistency for wall-bounded flows. However, the specific formulation delivered requires an averaging approach that introduces some application challenges, in particular being very sensitive to inlet boundary conditions and leading to spurious hybrid activation in open boundary external flows. This thesis assembles and demonstrates a new approach to support effective aerodynamic design and optimization through the delivery of an average-free STRUCT implementation applicable to all flow conditions. The new model introduces a source term in the [epsilon] equation of the standard k-[epsilon] model based on a time scale defined by the second invariant of the resolved velocity gradient tensor and therefore is named STRUCT-[epsilon] model. The new STRUCT-[epsilon] model is then validated on the fundamental cases and cases in the automotive industry, demonstrating improved accuracy in comparison with the most commonly used Realizable k-e model (RKE), at a comparable computational cost and with low mesh sensitivity. To further reduce the computational cost to support effective aerodynamic design, the extension of the STRUCT-[epsilon] model to fast running steady simulations is explored, and the results have shown improved performance with a better agreement with the reference data in comparison with the RKE model. On this basis, the STRUCT-[epsilon] model is applied to the optimization of a simplified tractor-trailer for demonstrating its value: at a computational cost amenable to industrial applications, it provides improved accuracy for the drag evaluation, and as a result, the optimal solution it generates through optimization is more accurate than the one obtained with the traditional RANS models.
Download or read book Automotive Aerodynamics written by Joseph Katz and published by John Wiley & Sons. This book was released on 2016-07-12 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: The automobile is an icon of modern technology because it includes most aspects of modern engineering, and it offers an exciting approach to engineering education. Of course there are many existing books on introductory fluid/aero dynamics but the majority of these are too long, focussed on aerospace and don’t adequately cover the basics. Therefore, there is room and a need for a concise, introductory textbook in this area. Automotive Aerodynamics fulfils this need and is an introductory textbook intended as a first course in the complex field of aero/fluid mechanics for engineering students. It introduces basic concepts and fluid properties, and covers fluid dynamic equations. Examples of automotive aerodynamics are included and the principles of computational fluid dynamics are introduced. This text also includes topics such as aeroacoustics and heat transfer which are important to engineering students and are closely related to the main topic of aero/fluid mechanics. This textbook contains complex mathematics, which not only serve as the foundation for future studies but also provide a road map for the present text. As the chapters evolve, focus is placed on more applicable examples, which can be solved in class using elementary algebra. The approach taken is designed to make the mathematics more approachable and easier to understand. Key features: Concise textbook which provides an introduction to fluid mechanics and aerodynamics, with automotive applications Written by a leading author in the field who has experience working with motor sports teams in industry Explains basic concepts and equations before progressing to cover more advanced topics Covers internal and external flows for automotive applications Covers emerging areas of aeroacoustics and heat transfer Automotive Aerodynamics is a must-have textbook for undergraduate and graduate students in automotive and mechanical engineering, and is also a concise reference for engineers in industry.
Download or read book Race Car Aerodynamics written by J Katz and published by Robert Bentley, Incorporated. This book was released on 1996-03-08 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book to summarize the secrets of the rapidly developing field of high-speed vehicle design. From F1 to Indy Car, Drag and Sedan racing, this book provides clear explanations for engineers who want to improve their design skills and enthusiasts who simply want to understand how their favorite race cars go fast. Explains how aerodynamics win races, why downforce is more important than streamlining and drag reduction, designing wings and venturis, plus wind tunnel designs and more.
Download or read book Aerodynamic Study on the Vehicle Shape Parameters with Respect to Ground Simulation written by Chenyi Zhang and published by Springer Nature. This book was released on 2021-02-24 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chenyi Zhang analyzes the influences of moving ground simulation technique in wind tunnel tests. In his work, the classical investigations on vehicle shape parameters with fixed ground conditions are reviewed with modern moving ground simulation technique. The investigations are performed by means of CFD simulations and model scale wind tunnel tests at IFS, University of Stuttgart. The shape parameters of two reference vehicles – the DrivAer and the AeroSUV model with notchback, fastback and estate back – are varied and investigated. The author presents different results in drag and lift for the varied geometry parameters. The classical results of the parametric study on the vehicle basic shapes for vehicle aerodynamics could be complemented with the findings of the present research.
Download or read book Progress in Vehicle Aerodynamics written by Jochen Wiedemann and published by . This book was released on 2000 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Aerodynamic Performance for Mass Produced Cars and Light Duty Trucks written by Road Vehicle Aerodynamics Forum Committee and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Recommended Practice provides a procedure for measuring and documenting the aerodynamic performance in a full-scale wind tunnel of passenger vehicles, i.e., mass-produced cars and light-duty trucks intended primarily for individual consumers. Testing or numerical modeling of pre-production and/or reduced-scale models is outside the scope of this document. Aerodynamic development procedures, i.e., methods to improve or optimize aerodynamic performance, are also excluded.It is well-known that aerodynamic performance results depend significantly on vehicle content and loading, as well as the wind tunnel itself (type, scale, and simulation qualities of the wind tunnel). Publication of non-standard test results causes unnecessary additional development work and incorrect perception of a vehicle's anticipated aerodynamic performance by government, academia, and the general public.The intent of this document is to promote uniformity and traceability of published aerodynamic performance data acquired in a wind tunnel, thereby enhancing the public reputation and credibility of the aerodynamics discipline in the total vehicle development process.Measurement of the aerodynamic performance according to this Recommended Practice requires a full-scale wind tunnel test on a production-ready, full-scale vehicle according to specifications for vehicle loading, content, and wind tunnel conditions.The measurement and resulting documentation for a particular vehicle shall be reported only by the company that intends to produce the vehicle. Whenever there is an opportunity for interpretation of the document, a good faith effort shall be made to obtain the vehicle's typical in-service performance and avoid finding the best possible performance under the best possible circumstances.Use of and compliance with this Recommended Practice is voluntary; however, it is mandatory for those advertising or otherwise publishing aerodynamic performance as "measured according to SAE J2881." Conversely, any advertised or otherwise published result carrying this or a substantially similar designation must have the necessary documentation accepted by and on file with the SAE in accordance with the procedures defined in this Recommended Practice.Appendices B and C contain the necessary submittal documents for compliance with this Recommended Practice. When a submittal is made, the chairman of the Road Vehicle Aerodynamics Forum Committee (RVAC) or his/her designee shall review the submittal for proper completion according to the requirements herein, but without consideration of the technical merit of the claimed performance. After the chairman's review, SAE will maintain an electronic database of all submittals.The database shall be available only to members and liasion members of the RVAC. Any RVAC member who retrieves information from the database shall do so with the understanding that the information is to be considered confidential within his or her company. This Recommended Practice defines the method for documenting road vehicle aerodynamic performance along with the associated vehicle set-up and full-scale wind tunnel conditions employed for the measurement. This is one of the key elements of achieving an overall aerodynamic certification standard for passenger vehicles.
Download or read book The International Vehicle Aerodynamics Conference written by IMechE and published by Woodhead Publishing. This book was released on 2014-11-03 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamics has never been more central to the development of cars, commercial vehicles, motorbikes, trains and human powered vehicles, driven by the need for efficiency: reducing carbon dioxide emissions, reducing fuel consumption, increasing range and alleviating problems associated with traffic congestion. Reducing vehicle weight makes it more challenging to ensure that they are stable and handle well over a wide range of environmental conditions. Lighter structures are also more vulnerable to aerodynamically induced vibration. Alongside this, customers demand an environment that is quiet, comfortable and maintains their vision of the world around them in all weathers. These aims must be met by designing vehicles that engage customers emotionally, promoting the brand values of manufacturers and operators. This can only be done by collaboration between designers and aerodynamicists. Examine the latest developments in vehicle aerodynamic development Explore opportunities to network and share experiences around different areas Focus on future challenges and the engineering knowledge and technology required to resolve them Discuss other areas of development including handling and stability, tyre aerodynamics and modelling, aeroacoustics and fluid structure interaction
Download or read book Road Vehicle Aerodynamic Design written by R. H. Barnard and published by Longman Publishing Group. This book was released on 1996 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text provides a comprehensive introduction to road vehicle aerodynamic design for students, engineers and designers working in the automotive field.
Download or read book A Century of Car Aerodynamics written by Julian Edgar and published by Independently Published. This book was released on 2021-05-31 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering every decade from the 1920s until now, this book reveals an incredible array of fascinating and advanced aerodynamic designs - cars shaped to cheat the wind or stick to the road. Meet an automotive inventor so weird he'd taken a vow of silence and had to communicate by writing notes... discover one of the lowest-drag cooling systems ever used in a production car... and see how the science and art of car aerodynamics have progressed over the last 100 years. Written with the full cooperation of car aerodynamicists from Porsche, Tesla, General Motors and Volkswagen, the coverage is detailed and accurate. Over 60 individual cars are described - from the tiny Fiat Uno to the mighty Bluebird Land Speed Record car. Learn about wings and spoilers, the Kamm tail and how today's low-drag electric cars are being developed. Be amazed that some cars built over 80 years ago have better aerodynamic figures than many current cars. See rare concept cars from Mercedes, Ford and Chrysler. Researched on three continents and containing more than 450 photos, diagrams and graphs, this book will forever change how you view car aerodynamics. "Someone once said that to know where you are going you need to know where you have come from. Julian Edgar's new book provides car aerodynamicists with a vivid and detailed understanding of how we got here over the past 100 years." Jeff Howell, Visiting Professor Loughborough University and former head of Aerodynamics at Rover, Jaguar Land Rover and Tata Motors European Technical Centre. "This book takes you on a fascinating and engrossing journey through the history of automotive aerodynamics, highlighting notable milestones in learning and technology, but also bringing real humanity to some of the illustrious names of the field, and adding illuminating context to their work." Rob Palin, lead aerodynamicist on the Tesla Model S "A fascinating and well-researched trip through history that will expand the understanding of anyone interested in vehicle aerodynamics." Jon Young, car aerodynamics enthusiast.
Download or read book The Aerodynamics of Heavy Vehicles III written by Andreas Dillmann and published by Springer. This book was released on 2015-08-19 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains papers presented at the International conference “The Aerodynamics of Heavy Vehicles III: Trucks, Buses and Trains” held in Potsdam, Germany, September 12-17, 2010 by Engineering Conferences International (ECI). Leading scientists and engineers from industry, universities and research laboratories, including truck and high-speed train manufacturers and operators were brought together to discuss computer simulation and experimental techniques to be applied for the design of more efficient trucks, buses and high-speed trains in the future. This conference was the third in the series after Monterey-Pacific Groove in 2002 and Lake Tahoe in 2007.The presentations address different aspects of train aerodynamics (cross wind effects, underbody flow, tunnel aerodynamics and aeroacoustics, experimental techniques), truck aerodynamics (drag reduction, flow control, experimental and computational techniques) as well as computational fluid dynamics and bluff body, wake and jet flows.
Download or read book Aerodynamics of Road Vehicles written by Wolf-Heinrich Hucho and published by Elsevier. This book was released on 2013-10-22 with total page 577 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamics of Road Vehicles details the aerodynamics of passenger cars, commercial vehicles, sports cars, and race cars; their external flow field; as well as their internal flow field. The book, after giving an introduction to automobile aerodynamics and some fundamentals of fluid mechanics, covers topics such as the performance and aerodynamics of different kinds of vehicles, as well as test techniques for their aerodynamics. The book also covers other concepts related to automobiles such as cooling systems and ventilations for vehicles. The text is recommended for mechanical engineers and phycisists in the automobile industry who would like to understand more about aerodynamics of motor vehicles and its importance on the field of road safety and automobile production.
Download or read book Automotive Aerodynamics written by Society of Automotive Engineers. Engineering Activity Board. Vehicle Configuration Committee of the Automobile Body Activity and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
