Criteria

Text:
Topic:
Display:

Results

Viewing 1 to 30 of 2505
Event
2015-06-22
This session is devoted to NVH issues arising within the aeronautical and aerospace industries, such as community noise, aircraft interior noise, aerospace vibro-acoustics, noise prediction, modeling and modal analysis.
Event
2015-06-22
This session is to present numerical and experimental work pertaining to noise due to flow around the vehicle body, such as flow-induced interior noise, flow over protrusions, sunroofs, windows, noise from ventilation systems, or flow noise in exhaust system. Papers on aerodynamics alone without sound are excluded. Numerical studies may include new models or models based on existing theory as long as they are adequately supported by experimental or theoretical verifications.
Event
2014-10-09
This session will address aerodynamic testing requirements, technologies, facilities and methods with a view toward improving efficiency and reducing emissions of medium and heavy commercial ground vehicles. Papers are solicited that address aerodynamic related corrections, correlations and assessments for various data sources including wind tunnel, and on-track/road testing.
Event
2014-10-09
This session will address aerodynamic testing requirements, technologies, facilities and methods with a view toward improving efficiency and reducing emissions of medium and heavy commercial ground vehicles. Papers are solicited that address aerodynamic related corrections, correlations and assessments for various data sources including wind tunnel, and on-track/road testing.
Event
2014-10-08
Aerodynamic drag reduction has been identified as a primary technology for increasing fuel economy and thus improving the economic health of the trucking industry as well as the environmental health of the US. The acceptance of aerodynamics as a major player in trucking efficiency has increased significantly over the past decade and this trend is expected to continue. Position papers on the current status and future role of aerodynamic technology on vehicle and vehicle component design are desired. Proposed papers should focus on the science and engineering challenges including atmospheric effects, trailer aerodynamics, tire and wheel aerodynamics and safety.
Event
2014-10-08
This session will address processes, strategies and techniques for the aerodynamic design and development of commercial vehicles and components with a view toward improving efficiency and reducing emissions. This topic includes aerocoustics and aerothermodynamics including underhood and cooling flows. Technical papers on the challenges and limitations of current design studies, tools, methods and processes are desired.
Event
2014-10-07
This two hour session will serve as an opening discussion on the growing regulatory environment associated with improving commercial vehicle aerodynamics and methods. Europe, Japan and North America (Canada, U.S. and California) regulatory groups as well as SAE are involved in the development of regulations for aerodynamic test and analysis methods. Industry experts from the EPA, NHTSA, NAS, EMA, NRC and more will discuss their views regarding the challenges and limitations of current and proposed regulatory methods. Don't miss your opportunity to have a face to face question and answer session with this dynamic lineup of speakers.
Technical Paper
2014-09-30
Haoting Wang, Tieping Lin, Xiayi Yuan, Qi Zhang
Three dimensional, steady state computational fluid dynamics (CFD) simulations of flow around a generic pickup truck are performed to optimize the aerodynamic performance of a pickup truck model. Detailed comparison between the data of the CFD model and the experiment are made. By using deformation techniques, surrogate models and optimization methods, the drag is reduced. Four design variables are used for deformation: the cabin height, bed height, ground clearance and bed length. The optimization is single objective: minimizing the drag coefficient. A response surface model is built to reduce the sampling points for optimization, and the simulation time is reduced accordingly. Results show that the design variables are not fully independent with each other, and by proper combinations of the variable change, the drag coefficient of the pickup truck model can be reduced effectively. In this study, the drag coefficient reduced about 9.7% through optimization algorithm. The results also show that the single tailgate itself is not always profitable for drag reduction.
Technical Paper
2014-09-30
Ashok Patidar, Shivdayal Prasad, Umashanker Gupta, Mohan Subbarao
In today's competitive world, vehicle with light weighting is the most focused area. Vehicle light weighting can be done either by using light weight materials or by reducing the size of the existing components. In present paper later approach of vehicle light weighting is followed. It will help in packaging and reduce weight will add benefit to FE too. Scope for light weighting is identified in exhaust system where muffler volume is optimized using CFD commercial tool FLUENT. The back pressure, exhaust gas temperature, sound noise level & sound quality are chosen as design verification targets. The muffler volume is reduced by 15% resultant system become 15% compact with 2% lighter weight. CFD results are well correlated with physical test results on both the existing and optimized design results. Detailed design guideline and simulation process of exhaust system is explained in this paper.
Technical Paper
2014-09-30
Michael S. Barton, David Corson, John Quigley, Babak Emami, Tanuj Kush
In this work, the multi-physics problem arising from fluid sloshing within a tanker truck undergoing acceleration is investigated through the use of bi-directional coupling between AcuSolve and MotionSolve. This application represents a challenging test case for simulation technology within the design of commercial vehicles. Computer aided engineering is playing a more predominant role in the design process for commercial and passenger vehicles. Better understanding the real time loading and responses on a vehicle during intended (or unintended) use can result in improved design and reduced cost over traditional assumptions. Sloshing of liquid within the cargo tank of a commercial tanker truck results in increased loading on the vehicle's suspension when undergoing different types of acceleration maneuvers. The change in loading can have a significant effect on the design of the vehicles suspension components and braking components. The ability to investigate the fully coupled behavior of the mechanical and fluid systems is a key technology to enable improved designs for these types of applications.
Technical Paper
2014-09-30
Colin Britcher, Wael Mokhtar, Stephen Way
Commercial vehicle design, as well as associated aerodynamic test procedures, acknowledge the fact that many of these vehicles will operate in strong crosswind conditions for a significant fraction of their operational life. For example, the SAE "wind averaged" drag coefficient develops a weighted average CD based on operation at representative speeds in representative winds from arbitrary directions. Wind tunnel testing at a representative road speed over a range of yaw angles of +-15° is sufficient to populate the SAE equation. However, wind tunnel tests of commercial vehicles are often compromised due to the physical size of the model or other factors, leading to various concerns. An on-road crosswind develops a deep atmospheric boundary layer profile. The vehicle's road speed results in the relative velocity field at the vehicle being strongly curved. A curved flow field is practically impossible to generate in a wind tunnel with a substantial mean velocity, although some yacht sail testing is carried out at in curved flow facilities at much lower velocities.
Technical Paper
2014-09-30
Marc Ratzel, Warren Dias
Multiple engineering disciplines are considered in the development process of modern vehicles. This includes disciplines such as aerodynamics and structural dynamics. Often, these disciplines are applied in isolation, that is, without the consideration of interactions between disciplines. But in order to accurately represent the physical environment in which these designs and vehicles operate, it becomes important to consider the interaction effects. Interaction effects can be considered by including the effects of the different disciplines in a sequential manner, such as, determining the aerodynamic loads with a computational fluid dynamics (CFD) solver and then using the computed forces as boundary conditions in a structural analysis solver to determine displacements and stresses. However, for certain applications where this sequential modeling approach is not representative, the multiple disciplines can be analyzed in a co-simulation environment. An example of this would be the fluttering of an automotive hood under driving conditions.
Technical Paper
2014-09-30
Shaoyun Sun, Yin-ping Chang, Xinyu Wang, Qiang Fu, Kelong Lu, Zuofeng Pan, Bo Li, Heinz Friz
A big challenge for the aerodynamic optimization of trucks is the limited availability of wind tunnels for testing full scale trucks. FAW wants to introduce a development process which is mainly based on CFD simulation in combination with some limited amount of wind tunnel testing. While accuracy and maturity of CFD simulation for truck aerodynamics has been demonstrated in recent years, a complete validation is still required before committing to a particular process. The CFD tools involved in this validation are Star CCM+ and PowerFLOW. Since there is currently no wind tunnel available in China for the testing of full scale trucks, a 70% scale model is built for testing in the Shanghai Automotive Wind Tunnel Center. Drag and surface pressures are measured for providing a good basis for comparison to the simulation results. The simulations are performed for the scale model geometry as well as for the full scale geometry of the fully detailed truck. As a completion of this validation study a test of the full scale truck with a shortened trailer in a suitable wind tunnel in Europe is planned as future work.
Technical Paper
2014-09-30
William Bradford Bartow, Andres C. Moreyra, Trevor Hirst, Gregory H. Woyczynski, Alexis lefebvre, Gecheng Zha
This paper experimentally investigates the detailed flow field of base drag reduction method using passive jet boat-tail (JBT) with 3D PIV measurement in wind tunnel testing. JBT is a new method recently developed by Zha et al to reduce vehicle base drag using passive jet instead of a solid botatail. It has the advantage of no blockage in the base area, which is important for vehicle loading/unloading and is necessary for vehicle rear view mirrors that can not permit any visibility blockage. The wind tunnel experiment indicates that the JBT significantly reduces the wake width and depth(Fig. 1), and thus the base drag. The unsteady wake flaps up and down and left and right. The hypothesis is that the wake flapping transfers the energy to the coherent structures caused by the jet, and then further energizes the base flow region with base pressure increased. The wake profile area at 1.5 length downstream is reduced by about 40%.The 3D PIV measurement found that the jet creates a large circumferential gradient of the flow field, which enhances the entrainment and energy transfer.
Technical Paper
2014-09-30
Shaoyun Sun, Yin-ping Chang, Qiang Fu, Jing Zhao, Long Ma, Shijie Fan, Bo Li, Andrea Shestopalov, Paul Stewart, Heinz Friz
In the development of an FAW SUV, one of the goals is to achieve a state of the art drag level. In order to achieve such an aggressive target, feedback from aerodynamics has to be included in the early stage of the design decision process. The aerodynamic performance evaluation and improvement is mostly based on CFD simulation in combination with some wind tunnel testing for validation of the simulation results. As a first step in this process, a fully detailed simulation model is built. The styling surface is combined with engine room and underbody detailed geometry from a similar size existing vehicle. From a detailed analysis of the flow field potential areas for improvement are identified and five design parameters for modifying overall shape features of the upper body are derived. In a second step, a response surface method involving DOE and adaptive sampling techniques is applied for characterizing the effects of the design changes. The characterization is followed by an optimization step to find the best possible drag improvement from these design changes.
Technical Paper
2014-09-30
Michael P. Lammert, Adam Duran, Jeremy Diez, Kevin Burton, Alex Nicholson
The objective of this research project was to compare fuel economy results of two class 8 tractor trailer combinations platooned together to a standalone tractor trailer combination. A series of twelve modified SAE Type II J1321 fuel economy track tests were used to document fuel economy performance of two platooned vehicles and a baseline vehicle at steady state speeds ranging from 55 mph to 70 mph, from a 20 ft following gap to 75 ft gap and at 65,000 lbs and 80,000 lbs as well as a variable speed platooned test. Additionally, coast down testing was performed on the vehicles in isolation and in platoon formation to quantify aerodynamic impacts of the platoon formation. All tractors involved had EPA Smartway compliant aerodynamics packages and trailers were equipped with side skirts. Testing took place at Uvalde Proving Grounds near San Antonio Texas funded by the Department of Energy (DOE) and managed by the National Renewable Energy Laboratory (NREL). Effects of vehicle speed and following gap on fuel economy were analyzed as well as effects on engine cooling and SCR aftertreatment performance.
Technical Paper
2014-09-30
Jeff Smith, Rick Mihelic, Brandon Gifford, Matthew Ellis
On-highway tractor-trailer vehicles operate in a complex aerodynamic environment that includes influences of surrounding vehicles. Typical aerodynamic analyses and testing of single vehicles on test track, in wind tunnel or in CFD do not account for these real world effects. However, it is possible with simulation and on-road testing to evaluate these aerodynamic interactions. CFD and physical testing of multiple vehicle interactions show that traffic interactions can impact the overall drag of leading and trailing vehicles. This paper will discuss results found in evaluating the effects of separation distances on tractor-trailer aerodynamics in on-road and CFD evaluations using a time-accurate Lattice Boltzmann Method based approach and the ramifications for improving real world prediction versus controlled single vehicle testing.
Technical Paper
2014-09-30
Jouke Van der Krieke, Gandert Van Raemdonck
Improving aerodynamic quality, i.e. reducing drag, of semi-trailers will contribute largely to reduce the fuel consumption and the emissions of harmful gases of heavy duty vehicles. In the recent past WABCO developed an aerodynamically shaped skirt, called SideWing, for a European tractor semi-trailer configuration. This solution proved its efficiency during wind tunnel experiments, dedicated track testing and operational testing on public roads. In the Netherlands one is allowed to drive with a longer vehicle combination having a length of 25m, instead of 16.5m for the standard length. This longer combination has a tractor, a semi-trailer and a drawbar trailer. The semi-trailer is equipped with SideWings, while the drawbar trailer has regular skirts. Together with the fleet operator a test was conducted during operational activities to determine the fuel savings of the SideWings with the skirts on this particular vehicle combination. This fuel saving test was conducted with only one vehicle for a total period of fifteen months.
Technical Paper
2014-09-30
Youhanna William, Walid Oraby, Sameh Metwally
When driving a vehicle on the road, the driver has to compensate continuously for small directional deviations from the desired course due to disturbances such as crosswinds and road irregularities leading to unintended path deviation. With higher and larger side area such as buses and trucks, the influence of crosswind on the vehicle lateral dynamics behavior is much higher and the vehicle becomes more sensitive to side wind excitations. The study presents a practical theoretical method to judge the aerodynamic response of buses in the early design steps based on both aerodynamic and design parameters. A constant longitudinal velocity 2-DOF vehicle lateral dynamics model is used to investigate a bus lateral response under nine different wind gusts excitations. An accurate validated 3-D CFD simulation model of the bus shape results is integrated with carefully chosen design parameters data of a real bus chassis and body to obtain vehicle lateral dynamic response to the prescribed excitations.
Technical Paper
2014-09-30
Mithun Shetty, Marius-Dorin Surcel
The forestry trucking industry is a major consumer of diesel fuel, and will be into the foreseeable future. One way to achieve fuel savings would be to reduce aerodynamic drag. Currently, aerodynamic improvements for forestry trailer configurations such as logging trailers are not fully understood and more research in this area is required. In most cases, logging trucks on their return trips are usually travelling in unloaded conditions with upright stakes, which add drag. CFD and wind tunnel testing suggested a drag reduction of up to 35% with no upright stakes, which corresponds to 17% in fuel savings in unloaded conditions. One of the proposed fuel reduction concepts was therefore to have foldable bunks so that the bunks or stakes could fold down into a horizontal position while travelling empty. The fuel savings were confirmed with track testing based on the SAE J1321 standard, which compared the fuel consumption of a vehicle with stakes in the horizontal position and a vehicle with stakes in the vertical position.
Technical Paper
2014-09-30
Helena Martini, Peter Gullberg, Lennart Lofdahl
Nowadays, much focus for the vehicle manufacturers is put on improving the energy efficiency of their products. The aerodynamic drag constitutes one major part of the total driving resistance for a vehicle driving at higher speeds. In fact, above approximately 80km/h the aerodynamic drag is the dominating resistance acting on a truck. Hence the importance of reducing this resistance is significant. Cooling drag is one part of the total aerodynamic drag, which arises from air flowing through the heat exchangers and the irregular underhood area. When using Computational Fluid Dynamics (CFD) in the development process it is of great importance to ensure that the methods used are accurately capturing the physics of the flow. This paper deals with comparative studies between CFD and wind tunnel tests. In this paper, two comparative studies are presented. One is a comparison between cooling performance simulations and climate wind tunnel measurements; the other study is a comparison between external aerodynamics CFD simulations and wind tunnel measurements.
Technical Paper
2014-09-30
Brian R. McAuliffe, Leanna Belluz, Marc Belzile
Terrestrial winds play an important role in affecting the aerodynamics of road vehicles. Of increasing importance is the effect of the unsteady turbulence structure of these winds and their influence on the process of optimizing aerodynamic performance to reduce fuel consumption. In an effort to predict better the aerodynamic performance of heavy-duty vehicles and various drag reduction technologies, a study was undertaken to measure the turbulent wind characteristics experienced by heavy-duty vehicles on the road. To measure the winds experienced on the road, a sport utility vehicle (SUV) was outfitted with an array of four fast-response pressure probes that could be arranged in vertical or horizontal rake configurations that provided measurements up to 4.0 m from the ground and spanning a width of 2.4 m. To characterize the influence of the proximity of the vehicle on the pressure signals of the probes, the SUV and its measurements system was calibrated in a large wind tunnel. On-road measurements of the turbulence intensities, turbulence length scales, wind spectra, and spatial correlations were performed.
Viewing 1 to 30 of 2505

Filter

  • Range:
    to:
  • Year: