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Viewing 1 to 30 of 2565
2016-04-12
Event
Paper offers on the following topics are welcome: test facilities, unsteady aerodynamics, fuel economy, cooling airflow, fundamental aerodynamics and aerodynamics development.
2015-10-08
Event
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. Specific topics to be discussed are aerodynamic related corrections, correlations and assessments for various data sources including wind tunnel, CFD, and on-track/road testing.
2015-10-08
Event
Future commercial vehicles will need to expand the use of advanced aerodynamic flow-control technologies to achieve significant levels of aerodynamic drag reduction and vehicle fuel economy improvements achieved with currently available with vehicle shaping and add-on fairings. This session will address passive and active flow control techniques for the cost effective management of aerodynamic drag with a view toward improving efficiency and reducing emissions.
2015-10-08
Event
The recognition and acceptance of aerodynamics as a major player in trucking efficiency has increased significantly over the past decade. The effective integration of aerodynamic concepts and technologies into future vehicles will require a multi-disciplinary/multi-design point approach. This session will address the current status and future role of aerodynamic design methods, tools and processes.
2015-10-07
Event
The need to reduce aerodynamic drag arising from cooling and thermal flows may increase as total vehicle drag is reduced. The complexity of this problem area will require advancements in both experimental and computational tools. Specific topics to be discussed are experimental and computational results as well the correlation of data sets from various sources for both the localized flow conditions as well a complete vehicle in operation.
2015-10-07
Event
Aerodynamics from Platooning and use of Long Combination Vehicles can improve overall aerodynamic efficiency and corresponding benefits to operating costs, fuel efficiency gains and emissions reductions. This session will discuss improvement opportunities and various trade-offs inherent in considering multiple vehicle/multiple trailer operations.
2015-09-29
Technical Paper
2015-01-2892
Carlos A. Pereira, Max Morton, Claire Martin, Geert-Jan Schellekens
The current trend towards energy efficient commercial vehicles requires a substantial improvement in their aerodynamic performance. The two largest contributions to the drag of a tractor-trailer combination are the wake at the rear of the trailer and the turbulent in-flow at the trailer gap. By integrating into the design of the roof fairing ducts that divert and speed-up air flow it is possible to obtain a reduction of drag in the trailer gap and alter the trailer wake favorably. The resulting decrease in yaw-averaged overall drag coefficient is of 5.8%. This translates into an improvement in fuel efficiency of 3% when compared to the baseline . The design optimization was performed using parametric variation of a computational fluid dynamic model at zero and six degree yaw.
2015-09-29
Technical Paper
2015-01-2884
Sam Waltzer, Julie Hawkins, Arvon Mitcham, Angus Lock, Dennis W. Johnson
The use of devices to reduce aerodynamic drag on large trailers and save fuel in long-haul, over-the-road freight operations has spurred innovation and prompted some trucking fleets to use them in combinations to achieve even greater gains in fuel-efficiency. This paper examines aerodynamic performance and potential fuel saving benefits of using trailer aerodynamic components in combinations based upon wind tunnel test data. Representations of SmartWay-verified trailer aerodynamic components were tested on a one-eighth scale model of a class 8 sleeper tractor and a fifty three foot, van trailer model. The open-jet wind tunnel employed a rolling floor to reduce floor boundary layer interference. The drag impacts of aerodynamic packages are evaluated for both van and refrigerated trailers. Additionally, the interactions between individual aerodynamic devices is investigated.
2015-09-29
Technical Paper
2015-01-2886
Kebing Tang, Li He, Yao Zhao, Heinz Friz, Bo Li
Abstract The development of a new Dongfeng Heavy truck had very strict targets for fuel consumption. As the aerodynamic drag plays a crucial role for the fuel consumption, a low drag value had to be achieved. It was therefore essential to include evaluation and optimization of the aerodynamics in the development process. Because wind tunnel facilities were not available, the complete aerodynamics development was based on digital simulation. The major portion of the aerodynamic optimization was carried out during the styling phase where mirrors, sun visor, front bumper and aero devices were optimized for drag reduction. For optimizing corner vanes and mud guards, self-soiling from the wheel spray was included in the analysis. The aero results did also show that cooling air flow rates are sufficiently high to ensure proper cooling. During the detailed engineering phase an increase of the drag above the target required further optimization work to finally reach the target.
2015-09-29
Technical Paper
2015-01-2893
Ashok Patidar, Umashanker Gupta, Ankur Bansal
Abstract Market driven competition in global trade and urgency for controlling the atmospheric air pollution are the twin forces, which have urged Indian automobile industries to catch up with the international emission norms. Improvement in the fuel efficiency of the vehicles is one way to bind to these stringent norms. It is experimentally proven that almost 40% of the available useful engine power is being consumed to overcome the drag resistance and around 45% to overcome the tire rolling resistance of the vehicle. This as evidence provides a huge scope to investigate the influence of aerodynamic drag and rolling resistances on the fuel consumption of a commercial vehicle. The present work is a numerical study on the influence of aerodynamic drag resistance on the fuel consumption of a commercial passenger bus. The commercial Computational Fluid Dynamics (CFD) tool FLUENT™ is used as a virtual analysis tool to estimate the drag coefficient of the bus.
2015-09-29
Technical Paper
2015-01-2895
Prasad Vegendla, Tanju Sofu, Rohit Saha, Mahesh Madurai Kumar, Long-Kung Hwang
Abstract This paper investigates the aerodynamic influence of multiple on-highway trucks in different platooning configurations. Complex pressure fields are generated on the highways due to interference of multiple vehicles. This pressure field causes an aerodynamic drag to be different than the aerodynamic drag of a vehicle in a no-traffic condition. In order to study the effect of platooning, three-dimensional modeling and numerical simulations were performed using STAR-CCM+® commercial Computational Fluid Dynamics (CFD) tool. The aerodynamic characteristics of vehicles were analyzed in five different platooning configurations with two and three vehicles in single and multiple lanes. A significant Yaw Averaged Aerodynamic Drag (YAD) reduction was observed in both leading and trailing vehicles. YAD was based on the average result of three different yaw angles at 0°, −6° and 6°. In single-lane traffic, YAD reduction was up to 8% and 38% in leading and trailing vehicles, respectively.
2015-09-29
Journal Article
2015-01-2898
Luigi Salati, Federico Cheli, Paolo Schito
Abstract The flow-field around a “common” European heavy truck, equipped with several different trailer devices, is investigated using steady and unsteady simulations. This work demonstrates how with simple devices added on the trailer it is possible to strongly decrease the aerodynamic drag over 10%, with an increase of overall dimensions below 1% without any change to the load capacity of the trailer. Several devices, installed on the trailer, are tested on a target vehicle and the shape of the “airbag”, the “fin”, the “boat tail” and the “front-rear trailer device” has been optimized to achieve the maximum in drag reduction in front wind. The performance of the optimized devices are tested also in cross wind conditions with the yaw angle varying from 0° to 30°. The truck equipped with the front-rear trailer device is also investigated using time variant simulation with yaw angle of 0°, 5°, 10°.
2015-09-29
Journal Article
2015-01-2890
Felix Hoffmann, Hanns-Joachim Schmidt, Christian Nayeri, Oliver Paschereit
The potential of drag reduction on a generic model of a heavy vehicle using base flaps operated in combination with passive and active flow control devices is investigated experimentally. Base flaps are well known as drag reduction devices for bluff bodies and heavy road vehicles. However, for optimal performance their deflection angle should typically not exceed 12°. The primary goal of ongoing investigations is to increase the usable range of the deflection angles by applying flow control. The secondary goal is to find the most suitable method for flow control. In this paper we compare triangular vortex generators and fluidic oscillators as passive and active flow control methods, respectively. These methods are used on declined surfaces or airfoils for shifting flow separation towards higher deflection angles. Vortex generators have the advantage of being very simple devices but produce drag. Fluidic oscillators are also quite simple devices but require additional air supply.
2015-09-29
Journal Article
2015-01-2885
Nicholas Schaut, Raja Sengupta
Abstract As part of the United States Department of Energy's SuperTruck program, Volvo Trucks and its partners were tasked with demonstrating 50% improvement in overall freight efficiency for a tractor-trailer, relative to a best in class 2009 model year truck. This necessitated that significant gains be made in reducing aerodynamic drag of the tractor-trailer system, so trailer side-skirts and a trailer boat-tail were employed. A Lattice-Boltzmann based simulation method was used in conjunction with a Kriging Response Surface optimization process in order to efficiently describe a design space of seven independent parameters relating to boat-tail and side-skirt dimensions, and to find an optimal configuration. Part 1 concerns a fully-skirted tractor-trailer system, and consists of an initial phase of optimization, followed by a mid-project re-evaluation of constraints, and an additional period of optimization.
2015-09-29
Journal Article
2015-01-2859
Richard Wood
The impact of Reynolds number on the aerodynamics and operational performance of commercial vehicles is discussed. All supporting data has been obtained from published experimental and computational studies for complete vehicles and vehicle components. A review of Reynolds number effects on boundary layer state, unsteady and steady flow, time dependent wake structure, interacting shear layer and separated flows is presented. Reynolds number modeling and simulation criteria that impact aerodynamic characteristics and performance of a commercial vehicle are shown. The concepts of dimensional analysis and flow similarity are employed to show that aerodynamics of commercial ground vehicles is only dependent on Reynolds number. The terminology of Roshko is adopted for discussing the variation in drag with Reynolds number in which the subcritical, transitional and transcritical flow regimes are defined for commercial vehicles.
2015-09-29
Journal Article
2015-01-2897
Rick Mihelic, Jeff Smith, Matthew Ellis
Modern aerodynamic Class 8 freight tractors can improve vehicle freight efficiency and fuel economy versus older traditional style tractors when pulling Canadian style A- or B-Train double trailer long combination vehicles (LCV's) at highway speeds. This paper compares the aerodynamic performance of a current generation aerodynamic tractor with several freight hauling configurations through computational fluid dynamics evaluations using the Lattice-Boltzmann methodology. The configurations investigated include the tractor hauling a standard 53' trailer, a platooning configuration with a 30' separation distance, and an A-Train configuration including two 48' trailers connected with a dolly converter. The study demonstrates CFD's capability of evaluating extremely long vehicle combinations that might be difficult to accomplish in traditional wind tunnels due to size limitations.
2015-09-29
Journal Article
2015-01-2896
Matthew Ellis, Joaquin Ivan Gargoloff, Raja Sengupta
Abstract The increasing importance of reducing greenhouse gas emissions and the ongoing evolution of vehicle-to-vehicle connectivity technologies have generated significant interest in platooning for commercial vehicles, where two or more vehicles travel in same traffic lane in relatively close proximity. This paper examines the effect of platooning on four increasingly aerodynamic tractor-trailer configurations, using a Lattice Boltzmann based CFD solver. Each platoon consisted of three identical tractor-trailer configurations traveling in the same lane at 65mph. Two different vehicle to vehicle gaps were studied, 5m and 9m, in addition to singleton (solitary) vehicles, representing an effectively infinite gap. Aerodynamic drag for the lead, middle, and trailing vehicle in the platooning configurations were compared to the corresponding single vehicle tractor-trailer configuration.
2015-09-29
Journal Article
2015-01-2894
Marius-Dorin Surcel, Mithun Shetty
Abstract The performance of several aerodynamic technologies and approaches, such as trailer skirts, trailer boat tails, gap reduction, was evaluated using track testing, model wind tunnel testing, and CFD simulation, in order to assess the influence of the design, position and combination of various aerodynamic devices. The track test procedure followed the SAE J1321 SAE Fuel Consumption Test Procedure - Type II. Scale model wind tunnel tests were conducted to have direct performance comparisons among several possible configurations. The wind tunnel tests were conducted on a 1/8 scale model of a tractor in combination with a 53-foot semi-trailer. Among others, the wind tunnel tests and CFD simulations confirmed the influences of trailer skirts' length observed during the track tests and that the wider skirt closer to the ground offer better results.
2015-09-29
Journal Article
2015-01-2891
Trevor Hirst, Chuanpeng Li, Yunchao Yang, Eric Brands, Gecheng Zha
Abstract This paper conducts experimental study and numerical large eddy simulation for the drag reduction effect of jet boat-tail passive flow control on bluff body models. The jet boat-tail for bluff bodies operates by surrounding a converging duct around the end of a bluff body where the base surface is located. The duct captures free stream and forms a high speed jet angled toward the center of the bluff body base surface circumferentially to have the effect of a boat tail. A rectangular prism bluff body representative of various motor vehicle shapes such as trucks, vans, SUVs is used in this study. The numerical Large Eddy Simulation shows that the jet boat-tail sucks in the forebody boundary layer due to the low base pressure and significantly thins the boundary layer. The jet interacts with the shear layer and creates large vortex structures that entrain the freestream to base flow and energize it.
2015-09-23
Event
This session will cover aero Stability & Control, loads, aeroelastics & flutter, flight control laws/flying qualities.
2015-09-23
Event
This session will cover flight vehicle performance and sizing, conceptual/preliminary design, MDO, aero-propulsion integration, design education.
2015-09-23
Event
This session will cover aero Stability & Control, loads, aeroelastics & flutter, flight control laws/flying qualities.
2015-09-23
Event
General Aerodynamics topics for flight vehicles of all types, including flow physics, applied aerodynamics of wings, tails, rotors, control surfaces, aero loads and wind tunnel testing.
2015-09-22
Event
Although UAS aerodynamics is for the most part similar to that of manned aircraft, some designs requirements are unique for micro to small and high altitude, long-endurance vehicles. This session discusses critical aspects of aerodynamics for fixed and rotary wing UAS along with lighter than air technologies.
Viewing 1 to 30 of 2565

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