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2014-12-12
Standard
AS755F
This SAE Aerospace Standard (AS) provides a performance station designation system for aircraft propulsion systems and their derivatives. The station numbering conventions presented herein are for use in all communications concerning propulsion system performance such as computer programs, data reduction, design activities, and published documents. They are intended to facilitate calculations by the program user without unduly restricting the method of calculation used by the program supplier. The contents of this document were previously a subset of AS755E. Due to the growing complexity of station numbering schemes and an industry desire to expand nomenclature descriptions, a decision was made to separate the “station numbering” and “nomenclature” contents of AS755 into two separate documents. AS755 will continue to maintain standards for station numbering. SAE Aerospace Standard AS6502 will maintain standards for classical nomenclature moving forward.
2014-09-30
Journal Article
2014-01-2445
Shaoyun Sun, Yin-ping Chang, Qiang Fu, Jing Zhao, Long Ma, Shijie Fan, Bo Li, Andrea Shestopalov, Paul Stewart, Heinz Friz
Abstract 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 verification 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 design of experiments and adaptive sampling techniques are applied for characterizing the effects of the design changes.
2014-06-17
Magazine
DuPont: from art to part DuPont's newly appointed global automotive technology director Jeffrey Sternberg, in conversation with Ian Adcock. Igniting the creative spark Ryan Gehm and Lindsay Brooke report on breakthrough technologies at the SAE Congress. Winning ways Ian Adcock exclusively reveals the newly formed Williams Advanced Engineering facility. Driverless future: steering a safe course Google unleashing 100 driverless, motorised pods on to the road has put the need for rigorous safety standards centre stage, as Ian Adcock reports
2014-05-07
Magazine
Defying convention Rapid prototyping has the potential to play a beneficial role in unconventional autonomous airship design. By reducing model cost, build time, difficulty of construction, and maintaining acceptable surface quality and finish, designers have greater ability to analyze several configurations of airships and to change the geometry to increase stability, reduce drag, or fulfill mission requirements.
2014-04-28
Technical Paper
2014-28-0032
Christian Fischer, Rainer Wagener, Tobias Melz, Heinz Kaufmann
Abstract The fatigue life approach is the main topic of structural durability. Improved methods for the numerical fatigue analysis should be based on experimental results. In some fields of material testing progress in research are very hard to achieve. Especially the regime of amplitudes below the knee point of the SN-curve with a huge number of load cycles to failure is one of these challenges with respect to fatigue tests. With standard testing devices, 108 to 1010 cycles cannot be achieved in a reasonable time span because of their low and limited testing frequencies or their inflexible control systems concerning variable amplitude loading. For this reason, a new piezo based testing facility has been developed by Fraunhofer LBF which is capable to master this challenge. Built up with a high performance piezo actuator and a specially designed high frequency load frame this testing facility enables test frequencies up to 1.000Hz and locking forces of 10kN.
2014-04-01
Technical Paper
2014-01-0817
Chenaniah Langness, Michael Mangus, Christopher Depcik
Abstract In order to perform cutting-edge engine research that applies to modern Compression Ignition (CI) engines, a sophisticated test cell is needed that allows control of the engine and its auxiliary systems. The primary obstacle to the completion of such a test cell is the up-front expense. This paper covers the construction of a low cost, single-cylinder engine test cell while demonstrating the type of research that can be accomplished along the way. The components necessary for the construction, instrumentation, and operation of such a test cell, neglecting emissions analysis equipment, can be obtained for less than $150,000. The engine utilized, a naturally-aspirated single-cylinder Yanmar L100V, was purchased as an engine-generator package.
2014-04-01
Journal Article
2014-01-0559
Michael Guerrero, Kapil Butala, Ravi Tangirala, Amy Klinkenberger
NHTSA has been investigating a new test mode in which a research moving deformable barrier (RMDB) impacts a stationary vehicle at 90.1 kph, a 15 degree angle, and a 35% vehicle overlap. The test utilizes the THOR NT with modification kit (THOR) dummy positioned in both the driver and passenger seats. This paper compares the behavior of the THOR and Hybrid III dummies during this oblique research test mode. A series of four full vehicle oblique impact crash tests were performed. Two tests were equipped with THOR dummies and two tests were equipped with Hybrid III dummies. All dummies represent 50th percentile males and were positioned in the vehicle according to the FMVSS208 procedure. The Hybrid III dummies were instrumented with the Nine Accelerometer Package (NAP) to calculate brain injury criteria (BrIC) as well as THOR-Lx lower legs. Injury responses were recorded for each dummy during the event. High speed cameras were used to capture vehicle and dummy kinematics.
2014-04-01
Technical Paper
2014-01-0611
Kevin R. Cooper, Miroslav Mokry
Abstract The solid-wall wind tunnel boundary correction method outlined in this paper is an efficient pressure-signature method that requires few wall-mounted pressures. These pressures are used to determine the strengths of model- and wake-representing singularities that are used with the method of images to calculate the longitudinal and lateral velocity increments induced by the wind tunnel walls. Two force correction models are presented that convert these velocity increments to force and moment corrections. The performances of the correction procedures are demonstrated by their application to data from two sets of four, geometrically identical, differently sized, simplified automotive models.
2014-04-01
Technical Paper
2014-01-0579
Gerhard Wickern
Abstract Open jet wind tunnels are normally tuned to measure “correct” results without any modifications to the raw data. This is an important difference to closed wall wind tunnels, which usually require wind tunnel corrections. The tuning of open jet facilities is typically done experimentally using pilot tunnels and adding final adjustments in the commissioning phase of the full scale tunnel. This approach lacked theoretical background in the past. There is still a common belief outside the small group of people designing and using open jet wind tunnels, that - similar to closed wind tunnels, which generally measure too high aerodynamic forces and moments without correction - open jet wind tunnels measure coefficient too low compared to the real world. The paper will try to show that there is a solid physical foundation underlying the experimental approach and that the expectation to receive self-correcting behavior can be supported by theoretical models.
2014-04-01
Journal Article
2014-01-0609
Daichi Katoh, Kensuke Koremoto, Munetsugu Kaneko, Yoshimitsu Hashizume
An air-dam spoiler is commonly used to reduce aerodynamic drag in production vehicles. However, it inexplicably tends to show different performances between wind tunnel and coast-down tests. Neither the reason nor the mechanism has been clarified. We previously reported that an air-dam spoiler contributed to a change in the wake structure behind a vehicle. In this study, to clarify the mechanism, we investigated the coefficient of aerodynamic drag CD reduction effect, wake structure, and underflow under different boundary layer conditions by conducting wind tunnel tests with a rolling road system and constant speed on-road tests. We found that the air-dam spoiler changed the wake structure by deceleration of the underflow under stationary floor conditions. Accordingly, the base pressure was recovered by approximately 30% and, the CD value reduction effect was approximately 10%.
2014-04-01
Journal Article
2014-01-0620
Austin Hausmann, Christopher Depcik
This study investigates the practicality of vehicle coast down testing as a suitable replacement to moving floor wind tunnel experimentation. The recent implementation of full-scale moving floor wind tunnels is forcing a re-estimation of previous coefficient of drag determinations. Moreover, these wind tunnels are relatively expensive to build and operate and may not capture concepts such as linear and quadratic velocity dependency along with the influence of tire pressure on rolling resistance. As a result, the method elucidated here improves the accuracy of the fundamental vehicle modeling equations while remaining relatively affordable. The trends produced by incorporating on road test data into the model fit the values indicated by laboratory tests. This research chose equipment based on a balance between affordability and accuracy while illustrating that higher resolution frequency equipment would further enhance the model accuracy.
2014-04-01
Journal Article
2014-01-0613
Dirk Wieser, Hanns-Joachim Schmidt, Stefan Müller, Christoph Strangfeld, Christian Nayeri, Christian Paschereit
The experimental investigation was conducted with a 25%-scaled realistic car model called “DrivAer” mounted in a wind tunnel. This model includes geometric elements of a BMW 3 series and an Audi A4, accommodating modular, rear-end geometries so that it represents a generalized modern production car. The measurements were done with two different DrivAer rear end configurations (fastback and notchback) at varying side-wind conditions and a Reynolds number of up to Re=3.2·106. An array of more than 300 pressure ports distributed over the entire rear section measured the temporal pressure distribution. Additionally, extensive flow visualizations were conducted. The combination of flow visualization, and spatially and temporally resolved surface pressure measurements enables a deep insight into the flow field characteristics and underlying mechanisms.
2014-04-01
Journal Article
2014-01-0587
Oliver Mankowski, David Sims-Williams, Robert Dominy
This paper outlines the creation of a facility for simulating on-road transients in a model scale, ¾ open jet, wind tunnel. Aerodynamic transients experienced on-road can be important in relation to a number of attributes including vehicle handling and aeroacoustics. The objective is to develop vehicles which are robust to the range of conditions that they will experience. In general it is cross wind transients that are of greatest significance for road vehicles. On-road transients include a range of length scales but the most important scales are in the in the 2-20 vehicle length range where there are significant levels of unsteadiness experienced, the admittance is likely to be high, and the reduced frequencies are in a band where a dynamic test is required to correctly determine vehicle response.
2014-04-01
Journal Article
2014-01-0598
Kenji Tadakuma, Takashi Sugiyama, Kazuhiro Maeda, Masashi Iyota, Masahiro Ohta, Yoshinao Komatsu
A new wind tunnel was developed and adopted by Toyota Motor Corporation in March 2013. This wind tunnel is equipped with a 5-belt rolling road system with a platform balance that enables the flow simulation under the floor and around the tires in on-road conditions. It also minimizes the characteristic pulsation that occurs in wind tunnels to enable the evaluation of unsteady aerodynamic performance aspects. This paper describes the technology developed for this new wind tunnel and its performance verification results. In addition, after verifying the stand-alone performance of the wind tunnel, a vehicle was placed in the tunnel to verify the utility of the wind tunnel performance. Tests simulated flow fields around the vehicle in on-road conditions and confirmed that the wind tunnel is capable of evaluating unsteady flows.
2014-04-01
Journal Article
2014-01-0615
Sofie Koitrand, Lennart Lofdahl, Sven Rehnberg, Adrian Gaylard
Automotive aerodynamics measurements and simulations now routinely use a moving ground and rotating wheels (MVG&RW), which is more representative of on-road conditions than the fixed ground-fixed wheel (FG&FW) alternative. This can be understood as a combination of three elements: (a) moving ground (MVG), (b) rotating front wheels (RWF) and (c) rotating rear wheels (RWR). The interaction of these elements with the flow field has been explored to date by mainly experimental means. This paper presents a mainly computational (CFD) investigation of the effect of RWF and RWR, in combination with MVG, on the flow field around a saloon vehicle. The influence of MVG&RW is presented both in terms of a combined change from a FG&FW baseline and the incremental effects seen by the addition of each element separately. For this vehicle, noticeable decrease in both drag and rear lift is shown when adding MVG&RW, whereas front lift shows little change.
2014-03-31
WIP Standard
AS4191A
This SAE Aerospace Standard (AS) provides a method for gas turbine engine performance computer programs to be written using FORTRAN COMMON blocks. If a "function-call application program interface" (API) is to be used, then ARP4868 and ARP5571 are recommended as alternatives to that described in this document. When it is agreed between the program user and supplier that a particular program shall be supplied in FORTRAN, this document shall be used in conjunction with AS681 for steady-state and transient programs. This document also describes how to take advantage of the FORTRAN CHARACTER storage to extend the information interface between the calling program and the engine subroutine.
2014-03-26
WIP Standard
AS6502
1.1 This SAE Aerospace Standard (AS) provides performance station designation and nomenclature systems for aircraft propulsion systems and their derivatives. 1.2 The parameter naming conventions presented herein are for use in all communications concerning propulsion system performance such as computer programs, data reduction, design activities, and published documents. They are intended to facilitate calculations by the program user without unduly restricting the method of calculation used by the program supplier. 1.3 The list of symbols presented herein will be used for identification of input and output parameters. These symbols are not required to be used as internal parameter names within the engine subprogram
2014-02-21
Standard
AS210
“Hot Day”, “Tropical Day”, “Standard Day”, “Polar Day”, and “Cold Day” are part of the lexicon of the aircraft industry. These terms are generally understood to refer to specific, generally accepted characteristics of atmospheric temperature versus pressure altitude. There are also other, less well-known days, defined by their frequency of occurrence, such as “1% Hot Day”, “10% Cold Day”, or “Highest Recorded Day”. These temperature characteristics have their origins in multiple sources, including U.S. military specifications which are no longer in force.
2014-02-13
Standard
ARP755D
This SAE Aerospace Recommended Practice (ARP) provides performance station designation and nomenclature systems for aircraft propulsion systems and their derivatives. The systems presented herein are for use in all communications concerning propulsion system performance such as computer programs, data reduction, design activities, and published documents.
2014-01-03
Standard
AS755E
This SAE Aerospace Standard (AS) provides performance station designation and nomenclature systems for aircraft propulsion systems and their derivatives. The systems presented herein are for use in all communications concerning propulsion system performance such as computer programs, data reduction, design activities, and published documents. They are intended to facilitate calculations by the program user without unduly restricting the method of calculation used by the program supplier. The list of symbols presented herein will be used for identification of input and output parameters. These symbols are not required to be used as internal parameter names within the engine subprogram.
2013-10-19
WIP Standard
ARP4868C
The SAE Aerospace Standard document AS681 is the parent document of this SAE Aerospace Recommended Practice (ARP). AS681 applies to Engine programs written to conform to this document. This ARP specifies a set of functions and their expected behaviors that constitute a function based Application Program Interface (API) for gas turbine engine customer programs. The functions specified in this API are delivered by the Supplier as part of the Engine model. This document defines generic language independent functions and specific appendices for implementations in C and Fortran. The function based API specified in this ARP represents an alternative to the Fortran COMMON block structure, as specified in AS4191, historically used to communicate with an engine program. The customer may request emulation of the AS4191 interface if desired.
2013-10-18
WIP Standard
ARP5571C
This document provides recommendations for several aspects of air-breathing gas turbine engine performance modeling using object-oriented programming systems. Nomenclature, application program interface, and user interface are addressed with the emphasis on nomenclature. The Numerical Propulsion System Simulation (NPSS) modeling environment is frequently used in this document as an archetype. Many of the recommendations for standards are derived from NPSS standards. NPSS was chosen because it is an available product. The practices recommended herein may be applied to other object-oriented systems. While this document applies broadly to any gas turbine engine, the great majority of engine performance computer programs have historically been written for aircraft propulsion systems. Aircraft and propulsion terminology and examples appear throughout.
2013-10-04
Standard
ARP5571B
This document provides recommendations for several aspects of air-breathing gas turbine engine performance modeling using object-oriented programming systems. Nomenclature, application program interface, and user interface are addressed with the emphasis on nomenclature. The Numerical Propulsion System Simulation (NPSS) modeling environment is frequently used in this document as an archetype. Many of the recommendations for standards are derived from NPSS standards. NPSS was chosen because it is an available product. The practices recommended herein may be applied to other object-oriented systems. While this document applies broadly to any gas turbine engine, the great majority of engine performance computer programs have historically been written for aircraft propulsion systems. Aircraft and propulsion terminology and examples appear throughout.
2013-09-17
Journal Article
2013-01-2285
Abdallah Ben Mosbah, Manuel Flores Salinas, Ruxandra Botez, Thien-my Dao
One of the hardest tasks involving wind tunnel characterization is to determine the air-flow condition inside the test section. The Log-Tchebycheff method and the Equal Area method allow calculation of local velocities from measured differential pressures on rectangular and circular ducts. However, these two standard methods for air flow measurement are limited by the number of accurate pressure readings by the Pitot tube. In this paper, a new approach is presented for wind tunnel calibrations. This approach is based on a limited number of dynamic pressure measurements and a predictive technique using Neural Network (NN). To optimize the NN, the extended great deluge (EGD) algorithm is used. Wind tunnel testing involves a large number of variables such as wind direction, velocity, rate flow, turbulence characteristics, temperature variation and pressure distribution on airfoils.
2013-09-17
Technical Paper
2013-01-2193
Alessandro Ceruti, Piergiovanni Marzocca, Casey Stockbridge
Scaled models are often used to check the aerodynamic performance of full scale aircraft and airship concepts, which have gone through a conceptual and preliminary design process. Results from these tests can be quite useful to improve the design of unconventional airships whose aerodynamics might be quite different from classical configurations. Once the airship geometry has been defined, testing is required to acquire aerodynamic data necessary to implement the mathematical model of the airship needed by the flight control system to develop full autonomous capabilities. Rapid prototyping has the great potential of playing a beneficial role in unconventional autonomous airship design similarly to the success obtained in the design process of conventional aircrafts.
2013-09-08
Technical Paper
2013-24-0175
Daniele Littera, Alessandro Cozzolini, Marc Besch, Mario Velardi, Daniel Carder, Mridul Gautam
Stringent emission regulations have forced drastic technological improvements in diesel after treatment systems, particularly in reducing Particulate Matter (PM) emissions. Those improvements generally regard the use of Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF) and lately also the use of Selective Catalyst Reduction (SCR) systems along with improved engine control strategies for reduction of NOx emissions from these engines. Studies that have led to these technological advancements were made in controlled laboratory environment and are not representative of real world emissions from these engines or vehicles. In addition, formation and evolution of PM from these engines are extremely sensitive to overall changes in the dilution process.
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