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Viewing 1 to 30 of 8761
2011-04-12
Technical Paper
2011-01-0158
Stephane Cyr, Kang-Duck Ih, Sang-Hyun Park
Aerodynamic simulation results are most of the time compared to wind tunnel results. It is too often simplistically believed that it suffice to take the CAD geometry of a car, prepare and run a CFD simulation to obtain results that should be comparable. With the industry requesting accuracies of a few drag counts when comparing CFD to wind tunnel results, a careful analysis of the element susceptible of creating a difference in the results is in order. In this project a detailed 1:4 scale model of the Hyundai Genesis was tested in the model wind tunnel of the FKFS. Five different underbody panel configurations of the car were tested going from a fully paneled car to a car without panels. The impact of the moving versus static ground was also tested, providing over all ten different experimental results for this car model.
2011-04-12
Technical Paper
2011-01-0161
Tsuneaki Ishima, Yasushi Takahashi, Haruki Okado, Yasukazu Baba, Tomio Obokata
In CFD (Computational Fluid Dynamics) verification of vehicle aerodynamics, detailed velocity measurements are required. The conventional 2D-PIV (Two Dimensional Particle Image Velocimetry) needs at least twice the number of operations to measure the three components of velocity ( u,v,w ), thus it is difficult to set up precise measurement positions. Furthermore, there are some areas where measurements are rendered impossible due to the relative position of the object and the optical system. That is why the acquisition of detailed velocity data around a vehicle has not yet been attained. In this study, a detailed velocity measurement was conducted using a 3D-PIV measurement system. The measurement target was a quarter scale SAE standard vehicle model. The wind tunnel system which was also designed for a quarter scale car model was utilized. It consisted of a moving belt and a boundary suction system.
2013-04-08
Journal Article
2013-01-1230
Steffen Ostendorff, Joerg Sachsse, Heinz-Dietrich Wuttke, Jorge Meza Escobar
This paper presents an adaptive test approach to improve the structural testing of printed circuit boards (PCB) found in electronic automotive components. The approach makes use of FPGAs available on the PCBs, and its applicability is supported by the global trend taking place in the automotive industry of replacing ASICs with programmable devices such as FPGAs. For structural testing of PCBs, Boundary Scan (BScan) is mostly used. However, BScan has the disadvantage of being a static test method due to the slow execution speed reducing the fault coverage concerning dynamic faults. FPGAs support BScan as well, but they also offer a vast number of programmable resources. These resources can be configured for testing purposes. Our approach is to speed-up the testing process during the PCB manufacturing by moving data intensive processing from the external software side (Test-PC) to the programmable hardware side on-board (FPGA), reducing the data transfer over the slow JTAG interface.
2013-04-08
Journal Article
2013-01-1228
Graciela Becci, Gunwant Dhadyalla, Alexandros Mouzakitis, James Marco, Andrew David Moore
Testing real-time vehicular systems challenges the tester to design test cases for concurrent and sequential input events, emulating unexpected user and usage profiles. The vehicle response should be robust to unexpected user actions. Sequence Covering Arrays (SCA) offer an approach which can emulate such unexpected user actions by generating an optimized set of test vectors which cover all possible t-way sequences of events. The objective of this research was to find an efficient nonfunctional sequence testing (NFST) strategy for testing the robustness of real-time automotive embedded systems measured by their ability to recover (prove-out test) after applying sequences of user and usage patterns generated by combinatorial test algorithms, considered as “noisy” inputs. The method was validated with a case study of an automotive embedded system tested at Hardware-In-the-Loop (HIL) level. The random sequences were able to alter the system functionality observed at the prove-out test.
2004-07-19
Technical Paper
2004-01-2474
Robert T. Bigelow, Richard R. Chu, Jay K. Ingham
This Life Support Laboratory consists of a simulator of the spacecraft called Nautilus, which houses Air Revitalization Subsystem, Atmospheric Control and Supply, and Fire Detection and Suppression in the Equipment Area. There are supporting facilities including a Human Metabolic Simulator, simulated Low and Moderate Temperature Coolant Loop, chemical analysis bench, purified water supply, vacuum and gas supplies. These facilities are scheduled to be completed and start to operate for demonstration purposes by March 2005. There are an ARES Ground Model (AGM) and a Trace Contaminant Control Assembly in the ARS. The latter will be integrated with the AGM and a Condensing Heat Exchanger. The unit of AGM is being engineered, built, and will be delivered in early 2005 by EADS Space Division. These assemblies will be operated for sensitivity analysis, integration and optimization studies. The main goal is the achievement for optimal recovery of oxygen.
2004-11-16
Technical Paper
2004-01-3415
Marcelo Lopes de Oliveira e Souza, Gilberto da Cunha Trivelato
In this work we discuss some types of simulation environments and laboratories, their characteristics and applications to the simulation and control of aerospace vehicles. This includes: the basic definitions, types and characteristics of simulators and simulations (physical, computational, hybrid, etc.; discrete events, discrete time, continuous time, etc; deterministic, stochastic, etc.) their basic compromise (simplicity × fidelity), their man-machine interfaces and interactions (virtual, constructive, live, etc.), their evolution law (time, events, mixed, etc.), their architectures (“stand-alone”, PIL, HIL, MIL, DIS, HLA, etc.), and especially, their environments (discrete, continuous, hybrid, etc.) and laboratories (physical, computational, hybrid, etc.), and their applications to the simulation and control of aerospace vehicles. This is illustrated by some examples driven from the aerospace industry.
2004-07-19
Technical Paper
2004-01-2317
Valter Perotto, Vincenzo Mareschi
ALTAN (ALenia Thermal ANalyser) is a tool developed in Alenia Spazio, for the thermal simulation of satellites. Distinctive features of ALTAN are the description of the system in terms of thermal objects that can be considered as high level primitives, the accurate modelling of the energy sources (planets and sun) and of the optical properties, the integration in a single tool of the steps of radiative, conductive and thermal calculations and of the post-process of the results. An example of ALTAN application is given for Bepi-Colombo mission to Mercury, in particular the modelling of the highly variable planet temperature and the directional optical properties of the planet surface.
2004-07-19
Technical Paper
2004-01-2309
R. V. Gavrylov, Yu. A. Melenevskiy, V. I. Dranovskiy, M. I. Koshkin
The stand rig facility for thermo-vacuum testing of Space vehicles (STVT), described in this paper, is intended for simulation of: space vacuum, cold Space environment, electromagnetic radiation by the Sun and Earth, and Earth-albedo, as well as determination of influence of these factors on thermal regime of hardware and instruments of SV.
2004-07-19
Technical Paper
2004-01-2307
Pierre Jamotton, Antonio Cucchiaro, Isabelle Domken
Both Planck and Herschel satellite are cryogenic payloads, the first one having a cold point around 0.1 [K], the second one around 0.3 [K]. Not only the detectors are cooled, but also major subsystems and systems of the spacecraft’s. The Centre Spatial de Liège (CSL) is involved in the testing of several parts of the spacecraft’s, starting from optical tests on the mirrors or on the telescopes, going on with cryogenic vibration testing of scientific focal plane instruments, ending with the full Planck spacecraft testing. Each test requires temperature lower than 20 [K], in volumes ranging from 1 [m3] to 60 [m3], cooling down several kilograms to more than one ton, and withstanding heat load up to 150 [W] in stabilization. These tests are done is 4 different facilities of CSL, linked to a common cold Helium network. This latter allows full flexibility for operation of the different facilities quasi independently.
2004-07-19
Technical Paper
2004-01-2311
Jih-Run Tsai, Chia-Ray Chen, Lou-Chuang Lee, Chiuder Hsiao, Marco Molina, Maddalena Cova, Alberto Franzoso, Joseph Burger
The thermal vacuum / thermal balance test design and execution are described in the paper for the qualification campaign of 37 electronic units flown with the payload of ISS (International Space Station), i.e., AMS-02 (Alpha Magnetic Spectrometer). The tests are run in 10 separate test campaigns, across a time frame of 3 years (2002–2005). The tests have been carried on at NSPO (National Space Program Office in Taiwan), maximizing the time usage of thermal vacuum facilities. During each experimental campaign several units are tested at the same time, sharing the vacuum chamber volume. Because independent heaters are applied to each unit, the electronic crates can be tested at temperature levels different from one another. The reliability of thermal analysis is enhanced at each thermal balance test, with the final aim to fully validate the thermal mathematical model deviating less than 3°C from actual measurements.
2004-07-19
Technical Paper
2004-01-2310
M. T. Pauken, G. M. Kinsella, K. S. Novak, G. T. Tsuyuki, C. J. Phillips
In January 2004, two Mars Exploration Rovers (MER) landed on the surface of Mars to begin their mission as robotic geologists. A year prior to these historic landings, both rovers and the spacecraft that delivered them to Mars, were completing a series of environmental tests in facilities at the Jet Propulsion Laboratory. This paper describes the test program undertaken to validate the thermal design and verify the workmanship integrity of both rovers and the spacecraft. The spacecraft, which contained the rover within the aeroshell, were tested in a 7.5 m diameter thermal vacuum chamber. Thermal balance was performed for the near earth (hot case) condition and for the near Mars (cold case) condition. A solar simulator was used to provide the solar boundary condition on the solar array. IR lamps were used to simulate the solar heat load on the aeroshell for the off-sun attitudes experienced by the spacecraft during its cruise to Mars.
2004-07-19
Technical Paper
2004-01-2319
Hume Peabody, Sharon Peabody
ThermPlot Pro is a Windows based, post-processing tool that interfaces with standard output files from many of the industry’s leading finite difference thermal modeling tools, including: SINDA/FLUINT, SINDA/G, ESATAN, TMG, TAK2000, and TSS. ThermPlot Pro takes the standard output from these tools and imports the data into a user created Microsoft Excel® workbook. From the ThermPlot interface, a user may define Tables or Plots of relevant data, group nodes together for simplification, create specialized parameters, or evaluate heat flow throughout a model using a specialized, interactive HeatMap workbook. Tabular data may include minimums, maximums, averages, or any selected timestep. It also includes the option to add user-defined limits to the tables and highlight data that is out of limit conditions. Plotted data allows the user full control over series properties (color, linetype, marker, etc) as well as control over the axes properties (minimum, maximum, major division, etc.)
2004-07-19
Technical Paper
2004-01-2321
M. C. Haupt, R. Niesner, R. Schlitt, F. Bodendieck, Ch. Strom
This paper will give an overview of the effort to develop a thermal engineering tool for space applications, which is based on open source software (OSS) tools. It will describe the architecture of the analysis system and discuss the considered OSS packages used as building blocks with respect to the integration aspect and the engineering capabilities. The discussion of the software is completed with the experiences in creating a web-based community.
2004-07-19
Technical Paper
2004-01-2320
Marco Molina, Paolo Vercesi
The paper presents the simulation and the performance evaluation for an innovative Temperature and Humidity Control in a manned orbiting module. Starting from the EcosimPro® modelling capabilities, a Space Station Module has been built and a standard Temperature and Humidity Control (THC) has been designed, based on a classical PID (Proportional, Integral, Derivative) controller, suitably developed. After that, a fuzzy logic controller has been dsigned and thanks to EcosimPro programmability a fuzzy logic controller block has been created. The controller have been sized and its performances suitably simulated. Performances of the innovative controller are checked against the standard control techniques.
2004-07-19
Technical Paper
2004-01-2336
Hilary R. Bollan, Richard Kearn, Adrian D. Carp, Alex C. Goodall, Jacob Ford
This paper investigates the use of an industry standard tube and closure method with the aim of replacing the existing glass tube. In order to accredit the tube the long-term stability of the samples was investigated in terms of accuracy, precision, and robustness with actual and control samples in the submarine environment and with control samples in the laboratory.
2004-07-19
Technical Paper
2004-01-2273
D. Martin
Traditionally, the preliminary thermal design is behind the mechanical and electrical spacecraft design. Many factors contribute to this including a lack of detailed physical characteristics of the spacecraft and knowledge of the distribution of the thermal loads within the spacecraft. Therefore, the thermal design typically reacts to the mechanical and electrical designs. The thermal analyst gets a configuration and then tries to wrap an acceptable solution around it. The analyst relies on years of experience and trial and error to determine the appropriate design cases and create a thermal design. Depending on the experience level of the engineer, several iterations may be necessary to determine the worst-case design points and an acceptable thermal design.
2004-07-19
Technical Paper
2004-01-2276
R. V. Gavrilov, V. N. Fenchenko, A. M. Kislov, V. G. Romanenko
The software package for computerized modeling of thermal regimes of a spacecraft (S/C) provided with passive and active means of temperature control, under conditions of orbital flight mission and at thermo-vacuum testing conditions, is represented. The programs of the package have been developed in Object Pascal programming language. Description of the package programs and their basic functions is outlined. An example of calculations for thermal regimes of satellite, with its longitudinal axis oriented on the Sun, is represented.
2004-07-19
Technical Paper
2004-01-2293
Edward Hodgson, Allison Bender, Joel Goldfarb, Gregory Quinn, Catherine Thibaud-Erkey, Fred Sribnik
An important, though often unstated, requirement to achieve NASA’s strategic goals will be an Extravehicular Activity (EVA) system that will let future astronauts work safely and effectively at the chosen destinations without imposing unacceptable burdens on the astronauts or the mission systems that support them. Past studies have shown that this may present an insurmountable challenge if pursued with current technologies and system design concepts. With funding from the NASA Institute for Advanced Concepts (NIAC), Hamilton Sundstrand has been studying a conceptual architecture for future EVA systems to meet this challenge. The Chameleon Suit concept shifts the EVA design paradigm from one in which the pressure garment and life support system are separate, largely independent subsystems to one in which the EVA system integrates distributed life support functions with the pressure suit.
2004-07-19
Technical Paper
2004-01-2306
A. Robson, S. Dolce, P. Ayache
MetOp is a series of three meteorology and climate monitoring satellites, which will be launched using the Russian Soyuz-Fregat vehicle over a period of 14 years starting in 2005. MetOp will form part of the American ‘Polar Orbiting Environmental Satellites’ (POES) programme, a further step in European/American collaboration in space. The MetOp satellites will fly in a sun-synchronous polar orbit at an altitude of between 800 and 850km, with a repeat cycle of 29 days. The satellite is based on the successful Spot platform, which has carried a number of European earth observation satellites over the last 15 years, and consists of two parts: 1. The Payload Module (or PLM) which carries twelve instruments, provided by the European Space Agency (ESA), the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the American National Oceanic and Atmospheric Administration (NOAA) and the French space agency, CNES. 2.
2004-07-19
Technical Paper
2004-01-2305
Juergen Schilke, Silvio Dolce, Elena Checa, Gaetan Piret
The METOP satellite is Europe’s polar-orbiting meteorological satellite. It balances the US provided POES (Polar Orbiting Environmental Satellite) program. 3 flight models are built under EUMETSAT/ESA contract by an industrial consortium led by Astrium. Instruments are supplied by NOAA and EUMETSAT. This paper gives a summary on the thermal testing of METOP payload module. The testing started with TB test on EM, conducted in may 2001 at ESTEC Large Space Simulator. It was followed by a TV test on the same model in June 2001. The test was split into a TB part with solar simulation and a TV part without. Between both tests a test jig carrying a set of stimuli and test equipment was installed on the PLM. In November 2002 the PLM flight model 1 was subjected to a TV test at ESTEC with additional TB phases to improve the TMM. In February 2004 PLM flight model 2 has executed also TV testing at ESTEC.
2004-07-19
Technical Paper
2004-01-2304
Christian Vettore, Federico Pamio, A. A. Sochivko, I. P. Lukaschuk, A. S. Smoljaninov
This paper describes the Thermal Balance test that has been performed on the PAMELA telescope Pressurized Container (PC) to verify the performance of the PC Thermal Control System (TCS). The PC will be attached outside the Russian satellite RESOURS DK to be flown in2004 The thermal control system of the PAMELA PC is based on a mechanical pumped loop fed with Isooctane as working fluid. The test has been performed with PAMELA Structural Thermal Model (STM) inside the PC to have representative interfaces for the thermal control system. Simulation of close-to-real flight environmental heat loads have been accomplished in a vacuum chamber by means of a complex system of IR lamps suitably oriented toward the PC and mechanically mounted on a tubular structure outside the PC. Overall test results have been excellent; PAMELA thermal control system thermal/fluidic requested performance have been verified. PAMELA telescope thermal interfaces have been confirmed as well.
2004-04-20
Technical Paper
2004-01-1817
Scott Gilchrist, Daniel Ewing, Chan Ching, Joseph Brand, Michael Dowhan
A new aero-engine nose cone anti-icing system using a rotating heat pipe has been proposed to replace the current method of blowing hot compressor bleed air over the nose cone surface. Here, the heat is transferred from a hot source within the engine to the nose cone through a rotating heat pipe along the central fan shaft. A compact evaporator is used at the evaporator end due to space constraints in the engine. The system is modeled as a thermal resistance network where the thermo-fluid dynamics of each component determine the resistors. This paper reviews each of the component models and results, which show that the evaporator thermal resistance is one of the limiting factors for adequate transfer of heat for anti-icing.
2011-04-12
Technical Paper
2011-01-0028
Luis Matallana, Luis Munoz, Juan Barreto
The development of vehicle navigation systems with low cost and medium uncertainty is necessary in order to perform an effective road vehicle fleet analysis. This work is a part of a project centered on the development of an integrated inertial - satellite navigation system which estimates in a very accurate way the kinematic variables of a vehicle during a set of different testing scenarios, including the development of driving cycles. A study for the uncertainty of the inertial navigation system is shown. The results provide criteria for the selection of the components of the system, including requirements on the satellite systems.
2011-05-17
Technical Paper
2011-01-1647
Kristopher Lynch, John Maxon
Gulfstream Aerospace Corporation (GAC) owns and operates an Acoustic Test Facility (ATF) in Savannah, GA. The ATF consists of a Reverberation Chamber, Hemi-Anechoic Chamber, and a Control Room. Types of testing conducted in the ATF include Transmission Loss, Sound Power, and Vibration testing. In addition to accommodating typical types of acoustic testing, the ATF has some unique capabilities. The ATF can be used to conduct testing at cold temperatures representative of up to 45,000 ft flight altitude, while simultaneously taking Transmission Loss measurements of the chilled test sample. Additionally, the ATF has the capability of conducting Transmission Loss testing of a full mockup of the aircraft sidewall, including a section of fuselage, all the thermal/acoustic materials up to and including the interior decorative panel. A sound source capable of very high amplitudes at high frequencies is required to obtain good measurements from testing multiple wall systems such as this.
2010-10-17
Technical Paper
2010-36-0538
Mario Triches Jr., Micael G. V. do Carmo, Vinicius L. Gouveia
Without available direct measurements, the only method of assessing the impact of a completely new aircraft or power-plant design is to utilize a reliable prediction procedure. Such a procedure may be able to make use if a limited amount of directly relevant data, for instance, engine test data, or may have to rely entirely upon empirical component prediction procedures. Traditional aircraft noise prediction procedures based on engine static noise data are generally costly in time, since the engine source separation process is not a straightforward task, demanding several side routines to make it feasible. This paper attempts to present a new and simplified approach to assess community noise levels of a new aircraft design based on static engine noise data. The simplified procedure proposes an alternative to the complete engine source separation process, based on the definition of master parameters like jet noise cut-off frequencies, tonal frequencies and resultant broadband spectra.
2010-10-17
Technical Paper
2010-36-0520
Delia Dimitriu, Dragos Munteanu, Octavian Pleter
This paper is assessing two methods that can be used in assessing the airport noise capacity when new operational practices are implemented at a certain airport. The example given is CDA-continuous descent approach implemented at Bucharest Henri Coanda International airport in Romania. A review of the main operational practices related to CDO (Continuous Descent Operations) with relevance for noise and emissions reduction, shows the importance of working in a team when implementing new operational practices, as well as the need to access data either through FDR (flight data recorder) or from measurements. - The example selected explains the difficulties one can have to extract FDR data. Although the authors of this paper benefitted from FDR from TAROM, the Romanian national airline, it was difficult to be extracted, so the assessment of the airport noise capacity focused on monitoring and measurements undertaken under the flight path.
2010-10-17
Technical Paper
2010-36-0514
Pieter Sijtsma
An introduction is given of phased array beamforming techniques for locating acoustic sources. Starting from basic principles, the Conventional Beamforming technique is described. It is explained how this technique can be applied to wind tunnel measurements. Further, a number of advanced array processing techniques are discussed. One chapter is devoted to the array processing technique for the location of moving sources. This technique can be applied to rotating sources, for example on wind turbine blades, and to source location on aircraft flying over a microphone array.
1999-10-19
Technical Paper
1999-01-5629
Martin Kraus, Rudolf Heinzinger, Hans-Christoph Oelker
Integration of ground-based testing into the airborne testing process is presented in terms of an advanced test and analysis concept. Based on the discussion, that running a simulator is less expensive than performing a test flight, means of combining both methodologies are being presented and discussed. The idea is to perform selected tests on ground-based facilities under test flight conditions. This is called Virtual Flight Testing. For explanation of this idea an example is given and a representative result is presented. Another main pillar of this advanced test and analysis concept is on-line analysis. A recent tool for this purpose is on-line simulation, which is introduced with a brief overview together with an illustrative example. The paper gives an introduction into DASA’s efforts to increase efficiency of the testing process. The main goal is an early feedback of test information into the design process in order to improve this process.
1999-10-19
Technical Paper
1999-01-5609
Richard L. Newman
In recent years, helicopter flight and mission information has migrated from conventional round mechanical dials mounted on the instrument panel to software-dependent head-mounted displays capable of showing many types of information. Test and evaluation techniques have not progressed commensurate with display technology. A formal test and evaluation program is proposed to ensure that new information displays support the pilot’s flight tasks. An outline of test requirements is presented for use in future flight display programs.
1999-10-19
Technical Paper
1999-01-5598
Gary A. Fleming, Hector L. Soto, Bruce W. South, Scott M. Bartram
An instrument development program aimed at using Projection Moiré Interferometry (PMI) for acquiring model deformation measurements in large wind tunnels was begun at NASA Langley Research Center in 1996. Various improvements to the initial prototype PMI systems have been made throughout this development effort. This paper documents several of the most significant improvements to the optical hardware and image processing software, and addresses system implementation issues for large wind tunnel applications. The improvements have increased both measurement accuracy and instrument efficiency, promoting the routine use of PMI for model deformation measurements in production wind tunnel tests.
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