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Viewing 1 to 30 of 2598
2016-06-15
Technical Paper
2016-01-1807
Olga Roditcheva, Lennart Carl Lofdahl, Simone Sebben, Pär Harling cEng, Holger Bernhardsson
Abstract This paper presents an experimental study of aeroacoustical sound sources generated by the turbulent flow around the side mirror of a Volvo V70. Measurements were carried out at the Volvo Cars aerodynamical wind tunnel (PVT) and at the aeroacoustical wind tunnel of Stuttgart University (FKFS). Several different measurement techniques were applied in both tunnels and the results were compared to each other. The configurations considered here were: side mirror with a cord and without the cord. The results discussed in this paper include intensity probe measurements in the flow around the side mirror, sound source localization with beamforming technique using a three-dimensional spherical array as well as standard measurements inside the car with an artificial head. This experimental study focused on understanding the differences between testing at the PVT and FKFS.
2016-06-15
Technical Paper
2016-01-1804
Stefan Becker, Katrin Nusser, Marco Oswald
Abstract Aim of the ongoing development of passenger cars is to predict the interior acoustics early in the development process. A significant noise component results from the flow phenomena in the area of the side window. Wind noise is a physical problem that involves the three complicated aspects each governed by different physics: The complex turbulent flow field in the wake of the a-pillar and the side mirror is characterized by velocity and pressure fluctuations. The flow field generates sound which is transmitted into the passenger cabin. In addition to that, it excites the structure, resulting in a radiation of structure-borne noise into the interior of the car. Therefore, the sound generation is governed by fluid dynamics of the air flow. The sound transmission through the structure due to vibrations is determined by structural mechanics of the body structure. The sound propagation inside the cabin is influenced by interior room acoustics.
2016-06-15
Technical Paper
2016-01-1803
Hannes Frank, Claus-Dieter Munz
Avoiding narrowband components in the acoustic spectrum is one of the most critical objectives in the automotive aeroacoustic optimization process. The underlying physical mechanisms are not completely understood. In a preceding numerical and experimental investigation, we performed large eddy simulations of an early-development stage realistic side-view mirror, where tonal noise was captured and the principle mechanisms were identified. In this contribution, we present simulations on a simplified two-dimensional geometry that is based on these findings. It is shown that the basic flow topology relevant for tonal noise generation on the original side-view mirror as well as the tonal noise source is reproduced in the 2D case. Furthermore, we present comparisons with measurements and the necessity and influence of a splitter plate downstream of the 2D body to avoid large scale vortex shedding.
2016-05-18
WIP Standard
AMS1424/3
This detail specification AMS1424/3 covers the use of In-Truck Manufacturing of a deicing SAE Type I deicing/anti-icing fluid. This detailed specification contains technical and other requirements that apply for the In-Truck Manufacturing of Type I deicing/anti-icing fluid.
2016-05-17
Magazine
Base-engine value engineering for higher fuel efficiency and enhanced performance Continuous improvement in existing engines can be efficiently achieved with a value engineering approach. The integration of product development with value engineering ensures the achievement of specified targets in a systematic manner and within a defined timeframe. Integrated system engineering for valvetrain design and development of a high-speed diesel engine The lead time for engine development has reduced significantly with the advent of advanced simulation techniques. Cars poised to become 'a thing' Making automobiles part of the Internet of Things brings both risks and rewards. Agility training for cars Chassis component suppliers refine vehicle dynamics at the high end and entry level with four-wheel steering and adaptive damping.
2016-05-09
WIP Standard
ARP4902C
This document provides information and guidance material to assist in assessing the need for and feasibility of developing deicing facilities, the planning (size and location) and design of deicing facilities, and assessing environmental considerations and operational considerations associated with de-icing facilities. The document presents relevant information necessary to define the need for a deicing facility and factors influencing its size, location and operation. The determination of the need for deicing facilities rests with Airports. Although this document intends to provide information to airport operator and deicing facility planner/designer, all stakeholders, including deicing service providers, should be involved in the development process.
2016-04-20
Standard
ARP6852A
This document describes methods that are known to have been used by aircraft manufacturers to evaluate aircraft aerodynamic performance and handling effects following application of aircraft ground deicing/anti-icing fluids (“fluids”), as well as methods under development. Guidance and insight based upon those experiences are provided, including: - Similarity Analyses - Icing Wind Tunnel Tests - Flight Tests - Computational Fluid Dynamics and other Numerical Analyses This document also describes: - The history of evaluation of the aerodynamic effects of fluids - The effects of fluids on aircraft aerodynamics - The testing for aerodynamic acceptability of fluids for SAE and regulatory qualification performed in accordance with AS5900 - Additionally, Appendices A to E present individual aircraft manufacturers’ histories and methodologies which substantially contributed to the improvement of knowledge and processes for the evaluation of fluid aerodynamic effects.
2016-04-14
Event
It's vital that we continue to explore fundamental aerodynamic effects and processes, to underpin future vehicle development. This two-part session underlines the importance of simplified models in building our understanding of wake structure, wheel rotation, cooling flows, onset flow turbulence and crosswinds. Beyond this, careful analysis of existing cars is used to provide further insights into multiple-vehicle platooning, and drag reduction technologies.
2016-04-14
Event
In this session the use of the Adjoint Method and its role in vehicle shape optimization will be explored. New simulation approaches will be presented, including Partially-Averaged Navier-Stokes (PANS) and a novel RANS and Implicit LES Hybrid Turbulence Model. The use of CFD for Cooling Drag sensitivity analysis is also discussed.
2016-04-14
Event
It's vital that we continue to explore fundamental aerodynamic effects and processes, to underpin future vehicle development. This two-part session underlines the importance of simplified models in building our understanding of wake structure, wheel rotation, cooling flows, onset flow turbulence and crosswinds. Beyond this, careful analysis of existing cars is used to provide further insights into multiple-vehicle platooning, and drag reduction technologies.
2016-04-13
Event
Experimental facilities and methods continue to develop. This session covers wind tunnel interferences and their correction, along with a new ground simulation system and methods for introducing atmospheric levels of turbulence into wind tunnel testing. Developments presented in measurement techniques include: Tomographic PIV, Quantitative Tuft Image Processing, Strip Tube pressure measurement and a new small-scale PIV system.
2016-04-13
Event
The emergence of unsteady simulation as a viable tool along with the continuing development of experimental methods has led to an increasing focus on the unsteady aerodynamic effects experienced by cars in use. This session investigates aerodynamics influences on vehicle dynamics: dynamic pitching, cross wind effects. Surface contamination is receiving increased attention as customer expectations rise. Hence, simulating soiling of rear vehicle surfaces and wetting of brake discs are explored.
2016-04-12
WIP Standard
J2881
This Recommend Practics provides a procedure for documenting the aerodynamic performance for passenger vehicles, i.e., mass-produced cars and light-duty trucks intended primarily for individual consumers.
2016-04-12
Event
Exploring the role of aerodynamics in Motorsports, from the development of a low-pitching-moment-helmet, through to combined aero-thermal testing and modelling aerodynamic effects on performance predictions. The session concludes with a survey of velocity fields and vortical structures around a Formula One Car, using PIV.
2016-04-12
Event
Aeroacoustics widely recognised as an important element in customer perceptions of vehicle quality. This session covers the simulation of rear side window buffeting, along with combining exterior time-resolved simulation with vibro-acoustics to predict wind noise in the cabin of a car.
2016-04-12
Event
Aerodynamics Development takes a practical view of the application of aerodynamics in industry. Starting with examining the use of CFD for the evaluation of early concepts, moving onto the development of a light truck - including on-road testing and culminating with drag reduction for EVs subject to crosswind.
2016-04-12
Event
Commercial vehicle aerodynamics is considered from both a component and test facility perspective. The effect of side-skirts is explored using a water tank. CFD is used to explore blockage effects in full scale wind tunnel tests. Finally, Scania’s New CD7 Climatic Wind Tunnel Facility for Heavy Trucks and Buses is described.
2016-04-12
WIP Standard
J1594
This terminology is intended to provide a common nomenclature for use in publishing road vehicle aerodynamics data and reports.
2016-04-12
Standard
J2084_201604
The scope of this SAE Information Report is confined to wind-tunnel testing, although it is recognized that many aspects of the aerodynamic characteristics of road vehicles can be investigated in other test facilities (such as water-tanks) or, especially, on the road. For example, coastdown testing is often used to determine aerodynamic drag (either in isolation or as part of the total resistance), and artificial gust generators are used to investigate the sensitivity of vehicles to cross-wind gusts. Also excluded from the present Report are climatic wind-tunnel tests of road vehicles, which are defined in more detail in Section 3. The Report covers the aerodynamic requirements of a wind-tunnel for automotive testing, together with the facility equipment needed and the requirements affecting the test vehicle or model.
2016-04-05
Technical Paper
2016-01-1618
Yoshihiro Okada, Takuji Nakashima, Makoto Tsubokura, Yousuke Morikawa, Ryousuke Kouno, Satoshi Okamoto, Tanaka Matsuhiro, Takahide Nouzawa
Abstract A road vehicle’s cornering motion is known to be a compound motion composed mainly of forward, sideslip and yaw motions. But little is known about the aerodynamics of cornering because little study has been conducted in this field. By clarifying and understanding a vehicle’s aerodynamic characteristics during cornering, a vehicle’s maneuvering stability during high-speed driving can be aerodynamically improved. Therefore, in this study, the aerodynamic characteristics of a vehicle’s cornering motion, i.e. the compound motion of forward, sideslip and yaw motions, were investigated. We also considered proposing an aerodynamics evaluation method for vehicles in dynamic maneuvering. Firstly, we decomposed cornering motion into yaw and sideslip motions. Then, we assumed that the aerodynamic side force and yaw moment of a cornering motion could be expressed by superposing linear expressions of yaw motion parameters and those of sideslip motion parameters, respectively.
2016-04-05
Technical Paper
2016-01-1621
Pruthviraj Mohanrao Palaskar
Abstract There are different techniques to reduce aerodynamic drag of a vehicle. Side tapering or boat-tailing is one of the methods to reduce drag of a vehicle. In this study instead of using very simple shape of a model, a more relevant simple car like shape resembling a hatchback vehicle is utilized. This shape of a simple car body has 10o diffuser angle. This hatchback model is modified digitally to give side tapering to it. The boat-tailing is restricted to sides of a vehicle and tapering is applied along the whole height of a vehicle. First a correlation study is performed between numerically predicted drag values and wind tunnel tested values. Effect of tapering with and without diffuser is also studied. An unexpected behavior is observed when removing a diffuser on base model caused reduction in drag values. Best tapering angles in both with and without diffuser cases are reported.
2016-04-05
Technical Paper
2016-01-1620
Jeff Howell, Sumit Panigrahi
Abstract Side force has an influence on the behaviour of passenger cars in windy conditions. It increases approximately linearly with yaw angle over a significant range of yaw for almost all cars and the side force derivative, (the gradient of side force coefficient with yaw angle), is similar for vehicles of a given category and size. The shape factors and components which affect side force for different vehicle types are discussed. The dominant influence on side force, for most cars, however, is shown to be the vehicle height which is consistent with slender wing theory if the car and its mirror image are considered. This simple theory is shown to apply to 1-box and 2- box shapes, covering most MPVs, hatchbacks and SUVs, but does not adequately represent the side forces on notchback and fastback car shapes. Data from simple bodies is used to develop a modification to the basic theory, which is applied to these vehicle types.
2016-04-05
Technical Paper
2016-01-1617
Yoshinobu Yamade, Chisachi Kato, Shinobu Yoshimura, Akiyoshi Iida, Keiichiro Iida, Kunizo Onda, Yoshimitsu Hashizume, Yang Gou
Abstract A wall-resolving Large Eddy Simulation (LES) has been performed by using up to 40 billion grids with a minimum grid resolution of 0.1 mm for predicting the exterior hydrodynamic pressure fluctuations in the turbulent boundary layers of a test car with simplified geometry. At several sampling points on the car surface, which included a point on the side window, the door panel, and the front fender panel, the computed hydrodynamic pressure fluctuations were compared with those measured by microphones installed on the surface of the car in a wind tunnel, and effects of the grid resolution on the accuracy of the predicted frequency spectra were discussed. The power spectra of the pressure fluctuations computed with 5 billion grid LES agreed reasonably well with those measured in the wind tunnel up to around 2 kHz although they had some discrepancy with the measured ones in the low and middle frequencies.
2016-04-05
Technical Paper
2016-01-1622
Miroslav Mokry
Abstract Lagally’s theorem is used to evaluate the increments to aerodynamic forces on automotive models, tested in solid-wall wind tunnels. The strengths of the model-representing singularities, pre-requisite for the application of the theory, are obtained from experimental wall pressure data, using an influence matrix method. The technique is demonstrated on the drag force acting on full-size and half-size truck models, measured in the same test section.
2016-04-05
Technical Paper
2016-01-1626
Hideyuki Kawamata, Satoru Kuroda, Shingo Tanaka, Munehiko Oshima
Abstract Reducing vehicle fuel consumption has become one of the most important issues in recent years in connection with environmental concerns such as global warming. Therefore, in the vehicle development process, attention has been focused on reducing aerodynamic drag as a way of improving fuel economy. When considering environmental issues, the development of vehicle aerodynamics must take into account real-world driving conditions. A crosswind is one of the representative conditions. It is well known that drag changes in a crosswind compared with a condition without a crosswind, and that the change depends on the vehicle shape. It is generally considered that the influence of a crosswind is relatively small since drag accounts for a small proportion of the total running resistance. However, for electric vehicles, the energy loss of the drive train is smaller than that of an internal combustion engine (ICE) vehicle.
2016-04-05
Technical Paper
2016-01-1578
Nicholas Simmonds, Panagiotis Tsoutsanis, Dimitris Drikakis, Adrian Gaylard, Wilko Jansen
Abstract Simulations are presented which fully couple both the aerodynamics and cooling flow for a model of a fully engineered production saloon car (Jaguar XJ) with a two-tier cooling pack. This allows for the investigation of the overall aerodynamic impact of the under-hood cooling flow, which is difficult to predict experimentally. The simulations use a 100 million-element mesh, surface wrapped and solved to convergence using a commercially available RANS solver (STARCCM+). The methodology employs representative boundary conditions, such as rotating wheels and a moving ground plane. A review is provided of the effect of cooling flows on the vehicle aerodynamics, compared to published data, which suggest cooling flow accounts for 26 drag counts (0.026 Cd). Further, a sensitivity analysis of the pressure drop curves used in the porous media model of the heat exchangers is made, allowing for an initial understanding of the effect on the overall aerodynamics.
Viewing 1 to 30 of 2598

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