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Viewing 1 to 30 of 3471
2017-04-11
Journal Article
2017-01-9450
Ali Reza Taherkhani, Carl Gilkeson PhD, Philip Gaskell PhD, Rob Hewson PhD, Vassili Toropov PhD, Amin Rezaienia PhD, Harvey Thompson
Abstract This paper investigates the optimization of the aerodynamic design of a police car, BMW 5-series which is popular police force across the UK. A Bezier curve fitting approach is proposed as a tool to improve the existing design of the warning light cluster in order to reduce drag. A formal optimization technique based on Computational Fluid Dynamics (CFD) and moving least squares (MLS) is used to determine the control points for the approximated curve to cover the light-bar and streamline the shape of the roof. The results clearly show that improving the aerodynamic design of the roofs will offer an important opportunity for reducing the fuel consumption and emissions for police vehicles. The optimized police car has 30% less drag than the non-optimized counter-part.
2017-04-06
Event
Paper offers on the following topics are welcome: test facilities, unsteady aerodynamics, fuel economy, cooling airflow, fundamental aerodynamics and aerodynamics development.
2017-04-06
Event
Paper offers on the following topics are welcome: test facilities, unsteady aerodynamics, fuel economy, cooling airflow, fundamental aerodynamics and aerodynamics development.
2017-04-05
Event
Paper offers on the following topics are welcome: test facilities, unsteady aerodynamics, fuel economy, cooling airflow, fundamental aerodynamics and aerodynamics development.
2017-04-05
Event
Paper offers on the following topics are welcome: test facilities, unsteady aerodynamics, fuel economy, cooling airflow, fundamental aerodynamics and aerodynamics development.
2017-04-05
Event
The purpose of this session is to bring awareness among the automotive aerodynamics, thermal and hydraulic systems development community to address the need of reliability analysis and robust design to improve the overall product quality. This session also introduces CAE based optimization of aero-thermal and fluid systems to improve automotive fuel economy. This session presents papers covering both testing and simulation.
2017-04-05
Event
The purpose of this session is to bring awareness among the automotive aerodynamics, thermal and hydraulic systems development community to address the need of reliability analysis and robust design to improve the overall product quality. This session also introduces CAE based optimization of aero-thermal and fluid systems to improve automotive fuel economy. This session presents papers covering both testing and simulation.
2017-04-04
Event
Paper offers on the following topics are welcome: test facilities, unsteady aerodynamics, fuel economy, cooling airflow, fundamental aerodynamics and aerodynamics development.
2017-04-04
Event
Paper offers on the following topics are welcome: test facilities, unsteady aerodynamics, fuel economy, cooling airflow, fundamental aerodynamics and aerodynamics development.
2017-03-28
Journal Article
2017-01-0441
Zhenyu Wang, Mei Zhuang
Abstract A numerical study on sunroof noise reduction is carried out. One of the strategies to suppress the noise is to break down the strong vortices impinging upon the trailing edge of the sunroof into smaller eddies. In the current study, a serrated sunroof trailing edge with sinusoidal profiles of wavelengths is investigated for the buffeting noise reduction. A number of combinations of wavelengths and amplitudes of sinusoidal profiles is employed to examine the effects of trailing edge serrations on the noise reduction. A generic vehicle model is used in the study and a straight trailing edge is considered as a baseline. The results indicate that the trailing edge serration has a significant impact on the sound pressure level (SPL) in the vehicle cabin and it can reduce the SPL by up to 10~15 dB for the buffeting frequency.
2017-03-28
Journal Article
2017-01-1510
Kisun Song, Kyung Hak Choo, Dimitri Mavris
Abstract In early phases of conceptual design stages for developing a new car in the modern automobile industry, the lack of systematic methodology to efficiently converge to an agreement between the aesthetics and aerodynamic performance tremendously increases budget and time. During these procedures, one of the most important tasks is to create geometric information which is versatilely morphable upon the demands of both of stylists and engineers. In this perspective, this paper proposes a Spline-based Modeling Algorithm (SMA) to implement into performing aerodynamic design optimization research based on CFD analysis. Once a 3-perspective schematic of a car is given, SMA regresses the backbone boundary lines by using optimum polynomial interpolation methods with the best goodness of fit, eventually reconstructing the 3D shape by linearly interpolating from the extracted boundaries minimizing loss of important geometric features.
2017-03-28
Journal Article
2017-01-1511
Anton Kabanovs, Graham Hodgson, Andrew Garmory, Martin Passmore, Adrian Gaylard
Abstract The motivation for this paper is to consider the effect of rear end geometry on rear soiling using a representative generic SUV body. In particular the effect of varying the top slant angle is considered using both experiment and Computational Fluid Dynamics (CFD). Previous work has shown that slant angle has a significant effect on wake shape and drag and the work here extends this to investigate the effect on rear soiling. It is hoped that this work can provide an insight into the likely effect of such geometry changes on the soiling of similarly shaped road vehicles. To increase the generality of results, and to allow comparison with previously obtained aerodynamic data, a 25% scale generic SUV model is used in the Loughborough University Large Wind Tunnel. UV doped water is sprayed from a position located at the bottom of the left rear tyre to simulate the creation of spray from this tyre.
2017-03-28
Journal Article
2017-01-1518
Emil Ljungskog, Simone Sebben, Alexander Broniewicz, Christoffer Landström
Abstract Many aerodynamic wind tunnels used for testing of ground vehicles have advanced ground simulation systems to account for the relative motion between the ground and the vehicle. One commonly used approach for ground simulation is a five belt system, where moving belts are used, often in conjunction with distributed suction and tangential blowing that reduces the displacement thickness of the boundary layer along the wind tunnel floor. This paper investigates the effects from aft-belt tangential blowing in the Volvo Cars Aerodynamic wind tunnel. First the uniformity of the boundary layer thickness downstream of the blowing slots is examined in the empty tunnel. This is followed by investigations of how the measured performance of different vehicle types in several configurations, typically tested in routine aerodynamic development work, depends on whether the tangential blowing system is active or not.
2017-03-28
Journal Article
2017-01-1517
Haidong Yuan, Zhigang Yang, Qiliang Li
Abstract External rear view mirror is attached at the side of the vehicle which is to permit clear vision for the driver to the rear of the vehicle. When the vehicle is running, the flow field around external rear view mirror is highly three-dimensional, unsteady, separated and turbulent which is known to be a significant source of aerodynamic noise and a contributor to the total drag force on the vehicle. While among all the researches on the flow field around external rear view mirror, different installation environment were employed. The external rear view mirror is mounted on a production car in most researches which presents the real condition and it can also be mounted on the ground of a wind tunnel, a specially designed table, or a generic vehicle model based on the SAE model. While, the relationship between the flow field around external rear view mirror and the installation environment is not very clear.
2017-03-28
Journal Article
2017-01-1513
Young-Chang Cho, Chin-Wei Chang, Andrea Shestopalov, Edward Tate
Abstract The airflow into the engine bay of a passenger car is used for cooling down essential components of the vehicle, such as powertrain, air-conditioning compressor, intake charge air, batteries, and brake systems, before it returns back to the external flow. When the intake ram pressure becomes high enough to supply surplus cooling air flow, this flow can be actively regulated by using arrays of grille shutters, namely active grille shutters (AGS), in order to reduce the drag penalty due to excessive cooling. In this study, the operation of AGS for a generic SUV-type model vehicle is optimized for improved fuel economy on a highway drive cycle (part of SFTP-US06) by using surrogate models. Both vehicle aerodynamic power consumption and under-hood cooling performance are assessed by using PowerFLOW, a high-fidelity flow solver that is fully coupled with powertrain heat exchanger models.
2017-03-28
Journal Article
2017-01-1512
Fuliang Wang, Zhangshun Yin, Shi Yan, Jia Zhan, Heinz Friz, Bo Li, Weiliang Xie
Abstract The validation of vehicle aerodynamic simulation results to wind tunnel test results and simulation accuracy improvement attract considerable attention of many automotive manufacturers. In order to improve the simulation accuracy, a simulation model of the ground effects simulation system of the aerodynamic wind tunnel of the Shanghai Automotive Wind Tunnel Center was built. The model includes the scoop, the distributed suction, the tangential blowing, the moving belt and the wheel belts. The simulated boundary layer profile and the pressure distribution agree well with test results. The baseline model and multiple design changes of the new Buick Excelle GT are simulated. The simulation results agree very well with test results.
2017-03-28
Journal Article
2017-01-1522
Thomas Blacha, Moni Islam
Abstract The aerodynamic development of the new Audi Q5 (released in 2017) is described. In the course of the optimization process a number of different tools has been applied depending on the chronological progress in the project. During the early design phase, wind tunnel experiments at 1:4 scale were performed accompanied by transient DES and stationary adjoint simulations. At this stage the model contained a detailed underbody but no detailed engine bay for underhood flow. Later, a full scale Q5 model was built up for the aerodynamic optimization in the 1:1 wind tunnel at Audi AG. The model featured a detailed underbody and engine bay including original parts for radiators, engine, axles and brakes from similar vehicles. Also the 1:1 experiments were accompanied by transient DES and stationary adjoint simulations in order to predict optimization potential and to better understand the governing flow.
2017-03-28
Journal Article
2017-01-1521
Levon Larson, Sudesh Woodiga, Ronald Gin, Robert Lietz
Abstract The airflow that enters the front grille of a ground vehicle for the purpose of component cooling has a significant effect on aerodynamic drag (engine airflow drag). Furthermore, engine airflow is known to be capable of influencing upstream external airflow (interference drag). The combined effect of these phenomena is commonly referred to as cooling drag, which generally contributes up to 10% of total vehicle drag. Due to this coupled nature, cooling drag is difficult to understand as it contains influences from multiple locations around the vehicle. A good understanding of the sources of cooling drag is paramount to drive vehicle design to a low cooling drag configuration. In this work, a production level Lincoln MKZ was modified so that a number of variables could be tested in both static ground and moving ground wind tunnel conditions. All tests were conducted at 80 MPH.
2017-03-28
Journal Article
2017-01-1520
Teddy Hobeika, Peter Gullberg, Simone Sebben, Lennart Lofdahl
Abstract Quantification of heat exchanger performance in its operative environment is in many engineering applications an essential task, and the air flow rate through the heat exchanger core is an important optimizing parameter. This paper explores an alternative method for quantifying the air flow rate through compact heat exchangers positioned in the underhood of a passenger car. Unlike conventional methods, typically relying on measurements of direct flow characteristics at discrete probe locations, the proposed method is based on the use of load-cells for direct measurement of the total force acting on the heat exchanger. The air flow rate is then calculated from the force measurement. A direct comparison with a conventional pressure based method is presented as both methods are applied on a passenger car’s radiator tested in a full scale wind tunnel using six different grill configurations.
2017-03-28
Journal Article
2017-01-1519
Arturo Guzman, Young-Chang Cho, John Tripp, Kumar Srinivasan
Abstract Pickup trucks are designed with a taller ride height and a larger tire envelope compared to other vehicle types given the duty cycle and environment they operate in. These differences play an important role in the flow field around spinning wheels and tires and their interactions with the vehicle body. From an aerodynamics perspective, understanding and managing this flow field are critical for drag reduction, wheel design, and brake cooling. Furthermore, the validation of numerical simulation methodology is essential for a systematic approach to aerodynamically efficient wheel design as a standard practice of vehicle design. This paper presents a correlation the near-wheel flow field for both front and rear spinning wheels with two different wheel designs for a Ram Quad Cab pick-up truck with moving ground. Twelve-hole probe experimental data obtained in a wind tunnel with a full width belt system are compared to the predictions of numerical simulations.
2017-03-28
Journal Article
2017-01-1530
Di Bao, Qing Jia, Zhigang Yang
Abstract Based on a 1:15 scaled 3/4 open jet automotive wind tunnel, this paper studies the effect of vortex generator on the buffeting phenomenon. The mean velocity, static pressure gradient, turbulent intensity as well as frequencies of fluctuant velocities have been explored experimentally with and without vortex generator. It shows that the less protruding vortex generator could control the buffeting phenomenon and improve the flow quality. Furthermore, the unsteady coherent structures in the jet shear layer have been visualized and analyzed by Detached-eddy simulation (DES). The vortex-ring pairing process is identified in the shear layer along with obvious frequency characteristics and velocity fluctuations. The vortex generator can postpone and restrain this vortex-ring pairing process, then reducing the velocity fluctuations.
Viewing 1 to 30 of 3471

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