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Pattinson, John. "Development and evaluation of a wind tunnel manoeuvre rig." Thesis, University of Bristol, 2010. http://hdl.handle.net/1983/6a7d4b89-aada-4e48-8d12-92cadeac3f2a.
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A novel wind tunnel rig, which can be used to collect data from high incidence, large amplitude manoeuvres is presented. The "manoeuvre rig" is a horizontal-pendulum type rig that is capable of large amplitude motions in up to five degrees of freedom. The rig consists of. two gimbals, an arm to provide an element of translation to the model centre of gravity, an aerodynamic compensation device, and a scale aircraft model. It is remotely controlled allowing largely unhindered motion and the potential for the investigation of feedback control laws. To assess the manoeuvre rig concept, a pilot rig was designed, manufactured and operated. For the tests, an existing approximate-scale model of the BAe Hawk aircraft is used. Mathematical models of the rig components and their dynamics are developed, with additions that account for friction. Small amplitude manoeuvres, typical of conventional testing, are performed. Mathematical models, describing the longitudinal aerodynamics of the Hawk, are fitted to this data using parameter estimation methods. Excellent results are achieved in the one degree-of-freedom pitch configuration. In two degrees-of-freedom pitch and heave, the results are not as good and the reasons for this are discussed. The Hawk model exhibits significant nonlinear behaviour at high angles of attack. This is thought to be related to dynamic stall and a suitable mathematical model is developed. Continuation and bifurcation analysis is used to analyse this model and fit it to experimental data. Qualitative agreement between the model and the data is achieved and influence of friction on the rig dynamics is discussed. The rig's capabilities are further evaluated by the demonstration of large amplitude, three degree of freedom (roll, pitch and yaw) tests, velocity vector rolls (roll and pitch) and four degree (roll, pitch, yaw and sway) of freedom snake-like motions. The manoeuvre rig is shown to be suitable for the extraction of longitudinal aerodynamic models. It is capable of generating small- and large-amplitude unsteady motions so that aircraft responses can be demonstrated and studied. As such, the rig shows promise for aerodynamic model extraction for nonlinear dynamics and departure
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Sanchez, Marc. "Etude des extracteurs d'air hybrides éoliens : conception de géométries et analyse des écoulements." Thesis, Perpignan, 2015. http://www.theses.fr/2015PERP0040/document.
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Ce travail de thèse concerne l'étude d'extracteurs d'air hybrides éoliens. Il se décompose en des investigations amont et appliquées. Dans la partie amont, des simulations fines ont été effectuées en conduite carrée avec et sans rotation, pour des nombres de Reynolds turbulents de l'ordre de 600, afin d'analyser l'impact de la rotation sur la turbulence. Elles ont montré que la rotation rompt la symétrie de l'écoulement. La partie appliquée est dédiée à la conception d'une nouvelle géométrie d'extracteur d'air. Cette géométrie a été proposée à partir de l'analyse de simulations RANS. Ses performances ont été confirmées par des mesures expérimentales sur banc d'essais. Les tests en soufflerie d'un système de captage d'énergie éolienne, conçu pour l'extracteur, ont mis en évidence son adéquation au régime de fonctionnement de l'extracteur. Les essais expérimentaux de l'extracteur complet, montrent que le système de captage apporte une part significative de l'énergie. Des essais en soufflerie ont permis d'observer le comportement global de l'extracteurThis PhD work concerns the study of hybrid air extractors. It is composed of upstream and applied investigations. In the upstream part, fine simulations are realized in square duct flow with and without rotation to analyse the impact of rotation on turbulence. It is found that rotation removes symmetry property of the flow with turbulent Reynolds number of 600. The applied part is dedicated to the conception of a new air extractor geometry. This geometry is proposed from the analyse of RANS simulations. Its performances are confirmed by experimental measurements on test rig. Wind tunnel tests of a wind power capturing system, designed for the extractor, show a good adequation to the operating regime of the extractor. Experimental investigations on the complete air extractor, show the wind power capturing system brings a significant part of the energy. Wind tunnel tests allow to observe the complete air extractor behaviour
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Davison, Paul M. "Development, modelling and control of a multi-degree-of-freedom dynamic wind tunnel rig." Thesis, University of Bristol, 2003. http://hdl.handle.net/1983/d597f4f7-acce-439e-a6b3-5d5858b3f592.
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Hamilton, Christianne Rhea. "Design of Test Sections for a High Enthalpy Wind Tunnel." MSSTATE, 2003. http://sun.library.msstate.edu/ETD-db/theses/available/etd-04082003-114126/.
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This document describes the design of a supersonic and a subsonic test section for a high enthalpy wind tunnel. A streamline is tracked through a supersonic test section using the method of characteristics. The specifics of the design program and the design techniques are illustrated for the supersonic section. The section of the paper dealing with the subsonic nozzle has a greatly diverse nature. This section details the inlet and exhaust restrictions and construction elements for the entire low speed system. The system is currently being set up for testing with the subsonic section, and the supersonic will eventually follow.
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Araujo-Estrada, Sergio A. "Control of a wind tunnel manoeuvre-rig to physically simulate free-flight motion of an aircraft model." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720851.
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De, La Presilla Román. "Fretting in Wind Power Pitch Bearings: Micro-Slip Experiments and Bearing Test Rig Design." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279489.
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Wind power is the fastest-growing form of green energy production in Europe, today accounting for 15% of the total power demand with 100.000 turbines installed. This tremendous development relied on a massive technological undertaking that must be continued, and even accelerated in order to meet the European Commission’s environmental goals for 2050. Currently, more active individual control of the rotor blades, turning the blade into and out of the wind, has proven its ability to reduce structural loads on the blades and other components significantly, therefore paving the road towards strong cost reductions. To allow for such adjustment, the rotor blades are connected to the rotor hub via pitch bearings. However, these new structural load reduction control strategies force the pitch bearings into a much more demanding operation condition. More frequent positioning activity and often in the form of smaller oscillating motions, when compared to traditional pitch control. This leading to an increased risk of wear damage of the pitch bearing that could fully incapacitate the blade control. At which point the safe regulation of the turbine can no longer be guaranteed and catastrophic failure, such as the loss of a rotor blade, is possible. This project pertains to the design a bearing test rig that can be used to test rolling element bearings with contact conditions that emulate those found in pitch bearings. A novel frameless motor-driven concept is proposed. The concept is aimed towards preventing unnecessary damage of non-test bearings and improving the dynamic performance of the test rig for a given motor capacity. One further objective of the project involved using an existing KTH single contact test rig to study the friction behavior of different lubricants when minute reciprocal tangential displacements are imposed.Vindkraft är idag det snabbast växande området för grön elproduktion i Europa och står med 100 000 installerade turbiner för 15% av den totala elförsörjningen. Denna otroliga utvecklingen har berott på en massiv teknologisk insats som måste fortsätta. För att nå Europakommissionens miljömål för 2050 måste expansionen av grön elproduktion och vindkraft till och med trappas upp. Nyligen har en mer aktiv individuell reglering av rotorbladen, vilket möjliggör att bladen kan styras in- och ut ur vinden, visat sig kunna reducera lasterna på blad och andra komponenter avsevärt, vilket därmed möjliggör stora kostnadsreduceringar. Dessa justeringar möjliggörs genom att rotorbladen ansluter hubben via ett rotorbladslager. Dessa nya lastreducerande reglerstrategier tvingar dock lagren att arbeta under högre belastning jämfört med traditionell reglering av rotorbladens lutningsvinkel. Det här sker genom mer frekvent positionering och ofta som små oscillerande rörelser, vilket leder till en högre risk för slitage på rotorbladslagren, som i sin tur kan leda till förlust av rotorbladsregleringen. När så sker kan inte längre en säker reglering av turbinen garanteras och katastrofala fel är möjliga, så som förlust av rotorblad. Det här projektet avser att utarbeta en design för en lagerprovningsrigg som kan användas för att testa rullager med kontaktvillkor som efterliknar de som återfinns i rotorbladslagren. Ett nytt koncept,m som är baserat på en ramlös motor, presenteras. Konceptet avser att förhindra onödigt slitage hos testriggens motorlager och förbättra de dynamiska egenskaperna för en given motorkapacitet. Projektet innefattar även en studie av friktionsbeteendet hos olika smörjmedel under små upprepande tangentiella rörelser, som utförts med en befintlig testrigg på KTH.
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Sparks, Russell. "A novel six degree of freedom dynamic wind tunnel test facility." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492066.
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Tourn, Cremona Silvana Cecilia. "Characterization of a New Open Jet Wind Tunnel to Optimize and Test Vertical Axis Wind Turbines." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/461079.
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Basat en el creixent interès en les tecnologies ambientals urbanes, l'estudi de turinas d'eix vertical de petita escala mostra desafiaments motivadors. En aquesta tesi, es presenten els criteris de disseny, les característiques i potencialitats d'un nou túnel de vent de secció de prova oberta. Té un àrea de sortida i la broquet del túnel de 1,5 x 1,5 m2, i es pot operar amb velocitats de sortida de 3 m / s a 17 m / s. La caracterització del flux s'ha dut a terme amb tubs pitot calibrats, anemòmetres de cassoletes i anemòmetres de fil calent. Es consideren dues configuracions diferents de l'àrea de prova, amb i sense sostre. Els mesuraments en el rang de velocitats de sortida disponibles mostren que la secció transversal, on les intensitats de velocitat i turbulència mostren un nivell acceptable d'uniformitat, té una àrea de 0,8 x 0,8 m2 i una dimensió de 2 m des de la sortida del broquet del túnel. En aquesta secció de treball, la intensitat màxima de la turbulència és del 4%. La caracterització detallada del flux realitzat indica que el túnel de vent es pot utilitzar per provar models a d'aerogeneradors de petita escala.Basado en el creciente interés en las tecnologías ambientales urbanas, el estudio de turinas de eje vertical de pequeña escala muestra desafíos motivadores. En esta tesis, se presentan los criterios de diseño, las características y potencialidades de un nuevo túnel de viento de seccion de prueba abierta. Tiene un área de salida e la boquilla del túnel de 1,5 x 1,5 m2, y se puede operar con velocidades de salida de 3 m/s a 17 m/s. La caracterización del flujo se ha llevado a cabo con tubos pitot calibrados, anemómetros de cazoletas y anemómetros de hilo caliente. Se consideran dos configuraciones diferentes del área de prueba, con y sin techo. Las mediciones en el rango de velocidades de salida disponibles muestran que la sección transversal, donde las intensidades de velocidad y turbulencia muestran un nivel aceptable de uniformidad, tiene un área de 0,8 x 0,8 m2 y una dimensión de 2 m desde la salida de la boquilla del túnel. En esta sección de trabajo, la intensidad máxima de la turbulencia es del 4%. La caracterización detallada del flujo realizado indica que el túnel de viento se puede utilizar para probar modelos a de aerogeneradores de pequeña escala.
Based on the increasing interest in urban environmental technologies, the study of small scale vertical axis wind turbines shows motivating challenges. In this thesis, we present the design criteria, characteristics and potentials of a new open jet wind tunnel. It has a nozzle exit area of 1.5 x1.5 m2, and it can be operated with exit velocities from 3 m/s to 17 m/s. The characterization of the flow has been carried out with calibrated pitot tubes, cup anemometers, and hot wire anemometers. Two different configurations of the test area, with and without a ceiling, are considered. Measurements in the range of available exit velocities show that the cross section, where the velocity and turbulence intensities show an acceptable level of uniformity, has an area of 0.8 x 0.8 m2 and a streamwise dimension of 2 m from the nozzle exit of the tunnel. In this working section, the maximum turbulence intensity is 4%. The detailed characterization of the flow carried out indicates that the wind tunnel can be used to test small scale models of wind turbines.
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Dalley, Sam. "Wind tunnel measurements on a low rise building and comparison with full-scale." Thesis, University of Surrey, 1993. http://epubs.surrey.ac.uk/886/.
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Capasso, Michael Anthony. "Construction and wind tunnel test of a 1/12th scale helicopter model." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA288487.
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Hamm, Christopher Eric. "AN ASSESSMENT OF FLOW QUALITY IN AN OPEN TEST SECTION WIND TUNNEL." MSSTATE, 2009. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11022009-115210/.
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The subsonic wind tunnel facility at Mississippi State University has been converted to an open test section configuration. An experimental setup was developed which is easily configurable to allow for further research. Measurements of flow quality over select portions of the test section were made to attain a basic understanding of the performance of the new configuration. A program was developed in LabVIEW to control a 3-axis traverse and perform necessary data reduction. The traverse control program was developed to perform data acquisition using a hot-film probe to facilitate the necessary measurements. Data was gathered at two wind tunnel velocity settings over several test section locations. Results of the testing program yielded recommendations on the use of the open configuration. This paper documents the procedure and setup of the testing program to include discussion of the control/data acquisition program and a discussion of the findings and recommendations.
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Westin, Michelle Fernandino. "Aeroelastic modeling and experimental analysis of a flexible wing for wind tunnel flutter test." Instituto Tecnológico de Aeronáutica, 2010. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1121.
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The objective of this work is to investigate the flutter phenomena experimentally, which will unify high aspect ratio wings design for wind tunnel flutter tests (Dowell and Tang, 2002), cheaper aeroelastic models construction and a procedure used by Sheta, Harrand, Thompson and Strganac (2002) to identify the flutter onset power spectral density versus the frequency. Initially, an experimental model developed by Dowell and Tang (2002) has been considered as a baseline model and, from this point, two new models with different wing configurations were determined, including the slender body at wing's tip, which is the idea extracted from Dowell's work, so that the torsion and bending modes are coupled (torsional moment of inertia reduction). The aeroelastic model can be divided into two parts: First, the wings structural dynamic models are computed using the finite element method implements in NASTRAN solver. sequently, ZAERO software is employed to compute the aeroelastic model. Unsteady aerodynamic loading is computed through a lifting surface interference method known as ZONA 6. The wing models defined as test beds will be constructed and tested in different wind tunnels, including open and closed tests section types. The power spectral density approach might be employed as a way to identify flutter. The output signal from an accelerometer placed in the wing structure allows, through its power spectral density computation, the identification of flutter onset condition and the corresponding undisturbed flow speed. The PSD function increase means flow energy extraction, a condition to have flutter. Experimental flutter speeds are close to the theoretically computed ones by ZAERO. From these observations, it is possible to validate the aeroelastic theoretical model in a small disturbance context. After flutter onset , the limit cycle oscillations are observed, fed by freestream energy extraction. The aeroelastic models under investigation in this research are excellent models for nonlinear aeroelastic phenomena behavior study.
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Ying, Pei. "Aerodynamic analysis of a novel wind turbine for an omni-flow wind energy system." Thesis, University of Hertfordshire, 2016. http://hdl.handle.net/2299/17355.
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The purpose of this research is to propose a novel wind turbine for an omni-flow wind energy system and investigate its aerodynamic performance. The geometry of the novel wind turbine is based upon the impulse turbine technology which has been successful in wave energy. In this study, both numerical and experimental studies were conducted to evaluate the aerodynamic features of this wind turbine. The numerical method was validated by a comparison between numerical and experimental results over a range of tip speed ratios. Results obtained from experiments and simulations indicate that the proposed wind turbine can be employed. Additionally, on the basis of the analyses performed, this new wind turbine has the potential for having a good startup feature, which means that this wind turbine can be suitable for applications in an urban environment. As an important component, the stator of this wind turbine can increase the passing flow velocity by 20%. Meanwhile, the passing flow direction also can be optimised by the stator. Aerodynamics of the wind turbine was analysed under the non-uniform flow condition, because the flow is non-uniform inside the omni-flow wind energy system. It was found that the maximum power coefficient of such a turbine under the non-uniform flow condition is lower than that under the uniform flow condition. Due to the non-uniform flow, the blades experience different flow velocities, and as a consequence, undergo different aerodynamic loads during one operation cycle. Thus the generated torque and thrust on a blade are subjected to frequent and periodical changes. Influences of the geometrical parameters on the aerodynamic characteristics of this wind turbine were investigated. From the initial study, it was found that changes of hub-to-tip ratios, numbers of blades, aerofoils and numbers of guide vanes, can significantly affect the II power performance. Additionally, the wind turbine obtained high values of maximum torque coefficients with changing geometrical parameters.
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Bin, Ab Wahab Abas. "The development of computer package for determining and solving pedestrian wind environmental discomfort and its wind tunnel validity test." Thesis, University of Salford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305099.
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Taylor, Nigel John. "Adaptive wall technology for two-dimensional wind tunnel testing at high subsonic through to low supersonic speeds." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294622.
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Broughton, Cabot A. Carleton University Dissertation Engineering Aeronautical. "Experimental investigation of slotted wall wind tunnel test sections for low interference road vehicle testing." Ottawa, 1990.
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Sidelko, Stephanie. "Benchmark of aerodynamic cycling helmets using a refined wind tunnel test protocol for helmet drag research." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40486.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (leaf 30).
The study of aerodynamics is very important in the world of cycling. Wind tunnel research is conducted on most of the equipment that is used by a rider and is a critical factor in the advancement of the sport. However, to date, a comprehensive study of time-trial helmets has not been performed. This thesis presents aerodynamic data for the most commonly used time-trial helmets in professional cycling. The helmets were tested at a sweep of yaw angles, from 0⁰ to 15⁰, in increments of 5⁰. The helmets were tested at three head angle positions at each yaw angle in order to best mimic actual riding conditions. A control road helmet was used to serve as a comparative tool. In order to maintain manufacturer confidentiality, the helmets were all randomly assigned variables. Thus, the thesis presents ranges of benefit and drag numbers, but does not rank by helmet name. The testing results showed that aerodynamic helmets offer drag reduction over a standard road helmet. The best and the worst performing helmets are all more aerodynamic than a road helmet.
by Stephanie Sidelko.
S.B.
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Ehrmann, Robert S. "Development of Measurement Methods for Application to a Wind Tunnel Test of an Advanced Transport Model." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/369.
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California Polytechnic State University, San Luis Obispo is currently working towards developing a Computational Fluid Dynamics (CFD) database for future code validation efforts. Cal Poly will complete a wind tunnel test on the Advanced Model for Extreme Lift and Improved Aeroacoustics (AMELIA) in the National Full-Scale Aerodynamics Complex (NFAC) 40 foot by 80 foot wind tunnel at NASA Ames Research Center in the summer of 2011. The development of two measurement techniques is discussed in this work, both with the objective of making measurements on AMELIA for CFD validation.
First, the work on the application of the Fringe-Imaging Skin Friction (FISF) technique to AMELIA is discussed. The FISF technique measures the skin friction magnitude and direction by applying oil droplets on a surface, exposing them to flow, measuring their thickness, and correlating their thickness to the local skin friction. The technique has the unique ability to obtain global skin friction measurements. A two foot, nickel plated, blended wing section test article has been manufactured specifically for FISF. The model is illuminated with mercury vapor lamps and imaged with a Canon 50D with a 546 nm bandpass filter. Various tests are applied to the wing in order to further characterize uncertainties related with the FISF technique. Human repeatability has uncertainties of ±2.3% of fringe spacing and ±2.0° in skin friction vector direction, while image post processing yields ±25% variation in skin friction coefficient. A method for measuring photogrammetry uncertainty is developed. The effect of filter variation and test repeatability was found to be negligible. A validation against a Preston tube was found to have 1.8% accuracy.
Second, the validation of a micro flow measurement device is investigated. Anemometers have always had limited capability in making near wall measurements, driving the design of new devices capable of measurements with increased wall proximity. Utilizing a thermocouple boundary layer rake, wall measurements within 0.0025 inches of the surface have been made. A Cross Correlation Rake (CCR) has the advantage of not requiring calibration but obtaining the same proximity and resolution as the thermocouple boundary layer rake. The flow device utilizes time of flight measurements computed via cross correlation to calculate wall velocity profiles. The CCR was designed to be applied to AMELIA to measure flow velocities above a flap in a transonic flow regime. The validation of the CCR was unsuccessful. Due to the fragile construction of the CCR, only one data point at 0.10589 inches from the surface was available for validation. The subsonic wind tunnel’s variable frequency drive generated noise which could not be filtered or shielded, requiring the use of a flow bench for validation testing. Since velocity measurements could not be made in the flow bench, a comparison of a fast and slow velocity was made. The CCR was not able to detect the difference between the two flow velocities. Currently, the CCR cannot be applied on AMELIA due to the unsuccessfully validation of the device.
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Unal, Sadullah Utku. "Design, Construction And Preliminary Testin Of An Aeroservoelastic Test Apparatus To Be Used In Ankara Wind Tunnel." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607034/index.pdf.
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In this thesis, an aeroservoelastic test appratus is designed to investigate the flutter phenomena in a low speed wind tunnel environment. Flutter is an aeroelastic instability that may occur at control surfaces of aircrafts and missiles. Aerodynamic, elastic, and inertial forces are involved in flutter. A mathematical model using aeroelastic equations of motion is derived to investigate flutter and is used as a basis to design the test setup. Simulations using this mathematical model are performed and critical flutter velocities and frequencies are found. Stiffness characteristics of the test setup are determined using the results of these simulations. The test setup is a two degrees of freedom system, with motions in pitch and plunge, and is controlled by a servomotor in the pitch degree of freedom. A NACA 0012 airfoil is used as a control surface in the test setup. Using this setup, the flutter phenomena is generated in Ankara Wind Tunnel (AWT) and experiments are conducted to validate the results of the theoretical aeroelastic mathematical model calculations.
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Szleper, Michele Lee. "Converging nozzle design for a subsonic wind tunnel to test heat sinks under impinging and parallel airflows." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/17124.
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Yu, Kevin Xin Jun. "Investigation of Recessed and Concealed Sprinklers Activation in Wind Tunnel Plunge Test and in BRANZFIRE Computer Model." Thesis, University of Canterbury. Civil Engineering, 2007. http://hdl.handle.net/10092/1184.
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Installation of exposed fire sprinklers may cause inconvenience in areas where architectural and interior presentation is significant. In order to overcome this inconvenience, recessed and concealed sprinklers were created and are applied widely. Response Time Index (RTI) and C-factor are the thermal sensitivity (intrinsic parameters) used to characterise a sprinkler. They are also used as input parameters in computer fire models to simulate sprinkler response time. However, the RTI and C-factor are not published by the manufactures. Therefore the RTI and C-factor of the recessed and concealed sprinklers have been analysed and determined in this research. In order to obtain the RTI of the recessed and concealed sprinklers, four of the most commonly used sprinkler models (two recessed and two concealed) in New Zealand have been investigated in plunge test experiment by using a wind tunnel in this research. The UC3 wind tunnel used to conduct the plunge test has been fabricated in this research. This work has demonstrated that the UC3 wind tunnel could provide a very stable and uniform temperature profile in the test section. However, the velocity uniformity of the tunnel needs to be improved in the future. The "apparent" RTI for different recessed and concealed sprinkler models (two recessed and two concealed) have been determined in the plunge test experiment. It should be noted that the "final calculated RTI" for each tested recessed and concealed sprinklers has been denoted as "apparent RTI" in this study. BRANZFIRE computer model has been used to model the fire scenarios in the full scale fire tests conducted by Bill and Heskestad (1995). The best input fire object location, the best input sprinkler distance below the ceiling and the input "apparent C-factor" in BRANZFIRE for the flush, recessed, concealed and the recessed sidewall sprinklers have been determined in this research. This work has generally improved the guidance available to fire safety engineers for the RTI and C-factor of the recessed and concealed sprinklers.
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Zientarski, Lauren Ann. "Wind Tunnel Testing of a Variable Camber Compliant Wing with a Unique Dual Load Cell Test Fixture." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1448893315.
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Lines, Philipp A. "Upgrade of a LabVIEW based data acquisition system for wind tunnel test of a 1/10 scale OH-6A helicopter fuselage." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FLines.pdf.
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Thesis (M.S. in Aeronautical Engineering)--Naval Postgraduate School, June 2003.Thesis advisor(s): E. Roberts Wood, Richard M. Howard. Includes bibliographical references (p. 53-54). Also available online.
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Fisher, David T. "Wind tunnel performance comparative test results of a circular cylinder and 50% ellipse tailboom for circulation control antitorque applications." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA283335.
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Brown, Kenneth Alexander. "A Study of Aerodynamics in Kevlar-Wall Test Sections." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/49383.
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This study is undertaken to characterize the aerodynamic behavior of Kevlar-wall test sections and specifically those containing two-dimensional, lifting models. The performance of the Kevlar-wall test section can be evaluated against the standard of the hard-wall test section, which in the case of the Stability Wind Tunnel (SWT) at Virginia Tech can be alternately installed or replaced by the Kevlar-wall test section. As a first step towards the evaluation of the Kevlar-wall test section aerodynamics, a validation of the hard-wall test section at the SWT is performed, in part by comparing data from NACA 0012 airfoil sections tested at the SWT with those tested at several other reliable facilities. The hard-wall test section showing good merit, back-to-back tests with three different airfoils are carried out in the SWT's hard-wall and Kevlar-wall test sections. Kevlar-wall data is corrected for wall interference with a panel method simulation that simulates the unique boundary conditions of Kevlar-wall test sections including the Kevlar porosity, wall deflection, and presence of the anechoic chambers on either side of the walls. Novel measurements of the boundary conditions are made during the Kevlar-wall tests to validate the panel method simulation. Finally, sensitivity studies on the input parameters of the panel method simulation are conducted. The work included in this study encompasses a wide range of issues related to Kevlar-wall as well as hard-wall tunnels and brings to light many details of the performance of such test sections.Master of Science
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Dwyer, William P. (William Patrick). "Measurement of flow boundary condition data and wing pressures in a wind tunnel test of a 45 deg swept wing." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/42182.
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Chen, Ru-Ching. "Development of a Supersonic Nozzle and Test Section for use with a Magnetic Suspension System for Re-Entry Aeroshell Models." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1544179612537658.
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Schouten, Shane Michael. "Complete CFD analysis of a Velocity XL-5 RG with flight-test verification." Texas A&M University, 2008. http://hdl.handle.net/1969.1/85894.
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The Texas A&M Flight Research Laboratory (FRL) recently received delivery of its
newest aircraft, the Velocity XL-5 RG. The Velocity can fly faster than the other aircraft
owned by the FRL and does not have a propeller in the front of the aircraft to disrupt the
air flow. These are definite advantages that make the Velocity an attractive addition to
the FRL inventory to be used in boundary-layer stability and transition control. Possible
mounting locations built into the aircraft for future projects include hard points in the
wings and roof of the fuselage. One of the drawbacks of the aircraft is that it has a
canard ahead of the main wing that could disrupt the incoming flow for a wing glove or
research requiring test pieces mounted to the hard point in the wing. Therefore, it is
necessary to understand the influence the canard and the impact of its wake on the wing
of the aircraft before any in-depth aerodynamic research could be completed on the
aircraft.
A combination of in-flight measurements of the canard wake and Computational
Fluid Dynamics (CFD) were used to provide a clear picture of the flowfield around the
aircraft. The first step of the project consisted of making a 3-D CAD model of the
aircraft. This model was then used for the CFD simulations in Fluent. 2-D, 3-D, inviscid,
and viscous simulations were preformed on the aircraft. A pressure rake was designed to
house a 5-hole probe and 18 Pitot probes that extended forward of the main wing to
measure the location and strength of the canard wake at various flight conditions. There
were five primary test points that were recorded at multiple times over the course of three flights. Once all of the data were collected from the flights, the freestream
conditions became the inputs into the final, 3-D CFD simulations on the aircraft.
The good agreement between the CFD results and the in-flight measurements
provided the necessary verification of the CFD model of the aircraft. These results can
be used in the future planning and execution of experiments involving the Velocity XL-5
RG.
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Scharnberg, Fábio Augusto. "Caracterização aerodinâmcia de edifícios através do espectro das cargas totais medidas em túnel de vento." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/181819.
Full textAbstract:
Nos últimos anos cresceu o interesse por construir edifícios cada vez mais altos, os quais estampam o poderio tecnológico e econômico das nações. Concomitantemente as estruturas se tornaram mais esbeltas e flexíveis e os fenômenos dinâmicos oriundos da ação do vento, que em edificações baixas não representam grande relevância no carregamento, começam a surgir e apresentar seus efeitos. Desta maneira, é importante conhecer como se desenvolve o escoamento do ar e a distribuição das pressões no entorno destas estruturas. Neste trabalho, caracteriza-se aerodinamicamente, através de dados oriundos de ensaios em túnel de vento, dois empreendimentos reais e presentes na engenharia nacional. Os carregamentos foram gerados através da integração simultânea de pressões e transformados em espectros de força, os quais auxiliam na visualização da energia cinética contida nas rajadas, na ocorrência de desprendimento cadenciado de vórtices, martelamento e na influência que as edificações vizinhas apresentam no escoamento. A análise é realizada local e globalmente, possibilitando verificar em que “zona”, ou faixa de altura, é mais significante para o carregamento da estrutura como um todo. O fenômeno de desprendimento de vórtices é caracterizado por um pico no espectro transversal à incidência do vento. Quando existem edificações ou obstáculos na região a barlavento, a estrutura pode ser martelada até a altura média destes obstáculos. Por fim, os resultados aqui apresentados podem servir de auxílio no pré-dimensionamento de estruturas com configurações similares, como comparativo e validação para pesquisas futuras e como referencial na elaboração de códigos normativos referentes ao tema. Destaca-se a importância de ensaios em túnel de vento, principalmente quando a estrutura a ser analisada possui um detalhamento arquitetônico complexo. Estes ensaios permitem ao projetista simular todos os casos de carregamento e os efeitos de vizinhança com maior confiabilidade e precisão em relação a métodos simplificados contidos, atualmente, em códigos e normas.In recent years many high-rise buildings have been built, which are a way to represent the economic and technological power of nations. Concomitantly, the structures have become slender and more flexible, and the dynamic phenomena of wind, which in low buildings do not represent a great relevance in the loading, start to show their effects. In this way, it is extremely important to know how the wind flow and the pressure distribution occur around these structures. In this research, two real projects, present in the national engineering, are characterized aerodynamically through data from wind tunnel tests. The loadings were processed through the simultaneous integration of pressures and transformed into force spectra, which aid in the visualization of the kinetic energy contained in the bursts, in the occurrence of vortex shedding, buffeting and the influence of the neighboring buildings on the wind flow. The analysis is performed locally and globally, making it possible to verify which "zone", or height range, is more significant to the loading of the structure as a whole. It can be seen that the phenomenon of vortex shedding is characterized by a peak in the crosswind spectrum and the buffeting phenomenon appears when there are buildings or obstacles in the windward region. Finally, the results presented here can be helpful in the pre-design of structures with similar configurations, in the comparison and validation for future researches and as a reference in the review of normative codes. Emphasis is given to the importance of wind tunnel testing, which allows the designer to simulate all loading cases and neighborhood effects with greater precision compared to simplified methods currently contained in codes and standards.
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Heim, Eugene Henry DeWendt. "Development of Methods for Improved Data Integrity and Efficient Testing of Wind Tunnel Models for Dynamic Test Conditions in Unsteady and Nonlinear Flight Regimes." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31050.
Full textAbstract:
Todayâ s high performance aircraft are operating in expanded flight envelopes, often maneuvering at high angular rates at high angles-of-attack, even above maximum lift. Current aerodynamic models are inadequate in predicting flight characteristics in the expanded envelope, such as rapid aircraft departures and other unusual motions. Unsteady flows of aircraft are of real concern. The ability to accurately measure aerodynamic loads directly impacts the ability to accurately model and predict flight. Current wind tunnel testing techniques do not adequately address the data fidelity of a test point under the influence of fluctuating loads and moments. Additionally, forced oscillation test techniques, one of the primary tools used to develop dynamic models, do not currently provide estimates of the uncertainty of the results during an oscillation cycle. Further, in testing models across a range of flight conditions, there are frequently parts of the envelope which are well behaved and require few data points to arrive at a sound answer, and other parts of the envelope where the responses are much more active and require a large sample of data to arrive at an answer with statistical significance. Currently, test methods do not factor changes of flow physics into data acquisition schemes, so in many cases data are obtained over more iterations than required, or insufficient data may be obtained to determine a valid estimate. Methods of providing a measure of data integrity for static and forced oscillation test techniques are presented with examples. A method for optimizing required forced oscillation cycles based on decay of uncertainty gradients and balance tolerances is also presented.Master of Science
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Perkins, Hugh Douglas. "Development and Demonstration of a Computational Tool for the Analysis of Particle Vitiation Effects in Hypersonic Propulsion Test Facilities." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1227553721.
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Wang, Haoting. "Experimental and Modeling Study of the Thermal Management of Li-ion Battery Packs." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/79660.
Full textAbstract:
This work reports the experimental and numerical study of the thermal management of Li-ion battery packs under the context of electric vehicle (EV) or hybrid EV (HEV) applications. Li-ion batteries have been extensively demonstrated as an important power source for EVs or HEVs. However, thermal management is a critical challenge for their widespread deployment, due to their highly dynamic operation and the wide range of environments under which they operate. To address these challenges, this work developed several experimental platforms to study adaptive thermal management strategies. Parallel to the experimental effort, multi-disciplinary models integrating heat transfer, fluid mechanics, and electro-thermal dynamics have been developed and validated, including detailed CFD models and lumped parameter models. The major contributions are twofold. First, this work developed actively controlled strategies and experimentally demonstrated their effectiveness on a practical sized battery pack and dynamic thermal loads. The results show that these strategies effectively reduced both the parasitic energy consumption and the temperature non-uniformity while maintaining the maximum temperature rise in the pack. Second, this work established a new two dimensional lumped parameter thermal model to overcome the limitations of existing thermal models and extend their applicable range. This new model provides accurate surface and core temperatures simulations comparable to detailed CFD models with a fraction of the computational cost.Ph. D.
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Kichkie, Nabil. "Comportement dynamique en lacet d'une eolienne a axe horizontal." Paris, ENSAM, 1987. http://www.theses.fr/1987ENAM0007.
Full textAbstract:
Determination de l'influence des parametres geometriques et aerodynamiques sur le comportement dynamique de la machine grace a la resolution du systeme d'equations differentielles qui caracterise le mouvement d'oscillation. Essais en soufflerie sur une maquette a l'echelle 1/3,5 permettant de determiner les couples de rappel ainsi que le coefficient de puissance et le comportement en lacet. Transposition des resultats de la maquette au prototype par l'application des lois de la similitude
34
Minair, Catherine. "Les angles privilégiés, grands invariants universaux : une approche par la dynamique des fluides, l'esthétique et la physio-biologie." Valenciennes, 1987. https://ged.uphf.fr/nuxeo/site/esupversions/a2fee09c-75f7-461c-88c5-71e89bf41c12.
Full textAbstract:
Des visualisations en soufflerie jusqu'à l'éclatement ont mis en évidence des relations de filiation entre les valeurs toujours privilégiées du système inter tourbillonnaire sur des ailes delta minces et les divers paramètres en particulier l'angle d'apex. L'universalité de la notion d'angle privilégié est soulignée par des considérations architecturales telles que le nombre d'or, et picturales en même temps que par des phénomènes biologiques confirmés par la géométrie, l'arithmétique et la psychophysiologie.
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Lemoult, Bernard. "Contribution a la connaissance des actions du vent sur les batiments a structure metallique." Poitiers, 1988. http://www.theses.fr/1988POIT2201.
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Etude experimentale a echelle reduite dans une soufflerie a couche limite (cstb, nantes), pour determiner le champ de pression; le role de la turbulence du vent amont sur les sollicitations extremes sur un batiment a ossature metallique est souligne
36
Di, Nicola Federico. "Energy harvesting from piezoelectric devices embedded in a 3D printed wing." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9705/.
Full textAbstract:
This thesis work has been carried out at Clarkson University in Potsdam NY, USA and involved the design of a low elongation wing, consisting of parts made by polylactide (PLA) using the fused deposition model (FDM) technology of Rapid Prototyping, then assembled together in a thin aluminum spar. The aim of the research is to evaluate the feasibility of collecting electrical energy by converting mechanical energy from the vibration of the wing flutter. With this aim piezoelectric stripes were glued in the inner part of the wing, as well as on the aluminum spar, as monomorphic configuration.
During the phases of the project, particular attention was given to the geometry and the materials used, in order to trigger the flutter for low flow velocity.
The CAD software SolidWorks® was used for the design of the wing and then the drawings were sent to the Clarkson machine shop in order to to produce the parts required by the wing assembly.
FEM simulations were performed, using software MSC NASTRAN/PATRAN®, to evaluate the stiffness of the whole wing as well as the natural vibration modes of the structure. These data, in a first approximation, were used to predict the flutter speed.
Finally, experimental tests in the Clarkson wind tunnel facility were carried out in order to validate the results obtained from FEM analysis. The power collected by the piezoelectrics under flutter condition was addressed by tuning the resistors downstream the electronic circuit of the piezoelectrics.
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Tarbadar, Rima. "Étude expérimentale en vraie grandeur et modélisation des pressions induites par le vent dans les combles : application à l'étanchéité des toitures à l'eau." Châtenay-Malabry, Ecole centrale de Paris, 1995. http://www.theses.fr/1995ECAP0414.
Full textAbstract:
La pénétration d'eau de pluie à travers une toiture à pentes constituée de petits éléments est principalement liée à la différence de pression externe et interne, générée par le vent sur le toit. Le champ de pression externe est accessible aux mesures, sur maquette en soufflerie atmosphérique. En revanche, le champ de pression interne ne peut pas être obtenue qu'en vraie grandeur. Une modélisation numérique de ce dernier a donc fait l'objet de cette thèse. Il s'agit plus précisement de calculer la pression instantanée en sous-face de la couverture, dotée ou non d'un écran qu'il soit souple ou rigide. L'estimation de la pression interne est délicate faute d'une bonne connaissance des caractéristiques de l'écoulement à travers des parois perméables. Une campagne de mesures en vraie grandeur a donc été menée pour caractériser la perméabilité à l'air de la toiture pour un revêtement donné (banc de mesures), ensuite pour étudier les effects de la vitesse et de la turbulence du vent et de l'intensité de la pluie sur cette perméabilité (soufflerie climatique). La pression interne issue du modèle sans écran reproduit bien celle mesurée. L'étude paramétrique du cas avec écran à montré la possibilité de réduire considérablement la pression différentielle. Une bonne connaissance des paramètres qui influencent le différentiel de pression permet de concevoir des toits à pentes, pour lesquels les problèmes de pénétration d'eau de pluie sont considérablement réduitsGenerally, the rain penetration through pitched lapped roofs is created by the difference of external and internal pressure, generated by the wind. In this thesis, a numerical model has been developped for prediction of internal pressure under the elements (the external pressure can be measured on a model in a boundary layer wind-tunnel). Two cases have been studied : roof without underlay, roof with flexible or stiff underlay. The dynamics of internal pressure is, in general, a complex problem. This is due to the poor knowledge on the leakage paths characteristics. Therefore, full-scale experimental studies have been carried out to characterize the roof wind permeability (test appartus) and to investigate the effects of windspeed, atmospheric turbulence and rain intensity on this permeability (climatic wind-tunnel). The analytical results were compared with full-scale results (roof without underlay case), and they matched closely. Parametric studies (underlay case) have shown that it is possible to reduce considerably the wind loads. Through a complete knowledge of the controlling parameters it will be possible to design and construct pitched lapped roofs, from which the problems of rain penetration is strongly reduced
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Moses, Kenneth C. "A Durable Terrestrial Drive Train for a Small Air Vehicle." Cleveland, Ohio : Case Western Reserve University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1270233578.
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Thesis (Master of Sciences (Engineering))--Case Western Reserve University, 2010Department of EMC - Mechanical Engineering Title from PDF (viewed on 2010-05-25) Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center
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Bonnardel, Xavier-Henri. "Etude théorique et expérimentale d'interactions aérodynamiques : application à l'effet de sol et à l'interaction rotor arrière-dérivé d'un hélicoptère." Aix-Marseille 2, 1987. http://www.theses.fr/1987AIX22059.
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Ferret, Bernard. "Etude expérimentale de l'intéraction entre un tourbillon isolé et un profil d'aile." Poitiers, 1988. http://www.theses.fr/1988POIT2317.
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En soufflerie subsonique, on genere un tourbillon a partir du decrochage dynamique d'un volet mis rapidement en incidence par commande numerique. Ce tourbillon unique et reproductible se detache et est convecte par l'ecoulement sur un profil naca0012. Cette maquette, montee sur une balance de portance et de trainee instationnaires est munie de prises de pression multiplexees sur un capteur par un commutateur pneumatique
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Journe, Paul. "Anémomètre ultrasonore corrélatif." Grenoble 1, 1989. http://www.theses.fr/1989GRE10128.
Full textAbstract:
Cette these retrace les etapes rencontrees lors du projet de recherche et developpement: mise au point d'un anemometre ultrasonore correlatif. Dans la premiere moitie du rapport sont presentes differents elements devant permettre de poser rigoureusement et precisemment le probleme: caracterisation d'un appareil repondant a un ensemble de besoins et de contraintes. Dans la deuxieme moitie du rapport sont presentees les experimentations et les etudes necessaires a la mise au point d'un anemometre prototype. Ces experiences sont relatives a la faisabilite de l'appareil aux methodes de traitement de l'information (correlation, statistiques, redondance), et aux problemes technologiques rencontres (lies surtout a l'utilisation des ultrasons dans l'air). Enfin, les resultats de tests de validation en soufflerie sont exposes
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Brožek, Petr. "Návrh zařízení pro měření aerodynamických sil a momentů v aerodynamickém tunelu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231647.
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The masters thesis is focused on design of the device for measurement of the aerodynamic forces and moments acting on radiators mounted in the wind tunnel test section. The thesis also includes the analysis of the aerodynamic drag which is produced by radiators and the LabView application software development.
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Zedník, Roman. "Příprava experimentálního měření aerodynamických charakteristik na zmenšeném modelu automobilu v aerodynamickém tunelu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417795.
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This master thesis focuses on designing of an external six-component balance. This universal concept would provide access of results from different models of wings, aircraft and automobiles with relatively small scales. This work also includes theoretical background needed in aerodynamic testing, analysis of 1D beam element model of scale and explanation of components used in scale. Lastly methods of calibration and measurement in aerodynamic tunnel are described, which can be adopted for this design to achieve the adequate level of accuracy.
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Villafañe, Roca Laura. "Experimental Aerothermal Performance of Turbofan Bypass Flow Heat Exchangers." Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/34774.
Full textAbstract:
The path to future aero-engines with more efficient engine architectures requires advanced
thermal management technologies to handle the demand of refrigeration and lubrication. Oil
systems, holding a double function as lubricant and coolant circuits, require supplemental
cooling sources to the conventional fuel based cooling systems as the current oil thermal
capacity becomes saturated with future engine developments. The present research focuses on
air/oil coolers, which geometrical characteristics and location are designed to minimize
aerodynamic effects while maximizing the thermal exchange. The heat exchangers composed
of parallel fins are integrated at the inner wall of the secondary duct of a turbofan. The
analysis of the interaction between the three-dimensional high velocity bypass flow and the
heat exchangers is essential to evaluate and optimize the aero-thermodynamic performances,
and to provide data for engine modeling. The objectives of this research are the development
of engine testing methods alternative to flight testing, and the characterization of the
aerothermal behavior of different finned heat exchanger configurations.
A new blow-down wind tunnel test facility was specifically designed to replicate the engine
bypass flow in the region of the splitter. The annular sector type test section consists on a
complex 3D geometry, as a result of three dimensional numerical flow simulations. The flow
evolves over the splitter duplicated at real scale, guided by helicoidally shaped lateral walls.
The development of measurement techniques for the present application involved the design
of instrumentation, testing procedures and data reduction methods. Detailed studies were
focused on multi-hole and fine wire thermocouple probes.
Two types of test campaigns were performed dedicated to: flow measurements along the test
section for different test configurations, i.e. in the absence of heat exchangers and in the
presence of different heat exchanger geometries, and heat transfer measurements on the heat
exchanger. As a result contours of flow velocity, angular distributions, total and static
pressures, temperatures and turbulence intensities, at different bypass duct axial positions, as
well as wall pressures along the test section, were obtained. The analysis of the flow
development along the test section allowed the understanding of the different flow behaviors
for each test configuration. Comparison of flow variables at each measurement plane
permitted quantifying and contrasting the different flow disturbances. Detailed analyses of the
flow downstream of the heat exchangers were assessed to characterize the flow in the fins¿
wake region. The aerodynamic performance of each heat exchanger configuration was
evaluated in terms of non dimensional pressure losses. Fins convective heat transfer
characteristics were derived from the infrared fin surface temperature measurements through a
new methodology based on inverse heat transfer methods coupled with conductive heat flux
models. The experimental characterization permitted to evaluate the cooling capacity of the
investigated type of heat exchangers for the design operational conditions. Finally, the
thermal efficiency of the heat exchanger at different points of the flight envelope during a
typical commercial mission was estimated by extrapolating the convective properties of the
flow to flight conditions.Villafañe Roca, L. (2013). Experimental Aerothermal Performance of Turbofan Bypass Flow Heat Exchangers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34774
TESIS
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de, Boer Hendrik. "Kalibrace měřícího zařízení aerodynamického tunelu VUT." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-449710.
Full textAbstract:
V této diplomové práci bylo zkoumáno téma kalibrace zařízení a sekcí ve vztahu k aerodynamickému tunelu na brněnském institutu leteckého inženýrství. Přístroje používané v aerodynamickém tunelu jsou kalibrovány a jsou popsány a provedeny kalibrace sekcí na testovací sekci. Kalibrační listy a šablony sestav jsou vytvořeny za účelem zjednodušení budoucích procesů. Nově kalibrovaná sestava se používá k provádění měření síly a probuzení na modelovém voze, která jsou porovnána s předkalibrací měření, aby dále ilustrovala užitečnost kalibrací.
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Hayati, Abolfazl. "Natural Ventilation and Air Infiltration in Large Single‑Zone Buildings : Measurements and Modelling with Reference to Historical Churches." Doctoral thesis, Högskolan i Gävle, Energisystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-24612.
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Natural ventilation is the dominating ventilation process in ancient buildings like churches, and also in most domestic buildings in Sweden and in the rest of the world. These buildings are naturally ventilated via air infiltration and airing. Air infiltration is the airflow through adventitious leakages in the building envelope, while airing is the intentional air exchange through large openings like windows and doors. Airing can in turn be performed either as single-sided (one opening) or as cross flow ventilation (two or more openings located on different walls). The total air exchange affects heating energy and indoor air quality. In churches, deposition of airborne particles causes gradual soiling of indoor surfaces, including paintings and other pieces of art. Significant amounts of particles are emitted from visitors and from candles, incense, etc. Temporary airing is likely to reduce this problem, and it can also be used to adjust the indoor temperature. The present study investigates mechanisms and prediction models regarding air infiltration and open-door airing by means of field measurements, experiments in wind tunnel and computer modelling. In natural ventilation, both air infiltration and airing share the same driving forces, i.e. wind and buoyancy (indoor-outdoor temperature differences). Both forces turn out to be difficult to predict, especially wind induced flows and the combination of buoyancy and wind. In the first part of the present study, two of the most established models for predicting air infiltration rate in buildings were evaluated against measurements in three historical stone churches in Sweden. A correction factor of 0.8 is introduced to adjust one of the studied models (which yielded better predictions) for fitting the large single zones like churches. Based on field investigation and IR-thermography inspections, a detailed numerical model was developed for prediction of air infiltration, where input data included assessed level of the neutral pressure level (NPL). The model functionality was validated against measurements in one of the case studies, indicating reasonable prediction capability. It is suggested that this model is further developed by including a more systematic calibration system for more building types and with different weather conditions. Regarding airing, both single-sided and cross flow rates through the porches of various church buildings were measured with tracer gas method, as well as through direct measurements of the air velocity in a porch opening. Measurement results were compared with predictions attained from four previously developed models for single‑sided ventilation. Models that include terms for wind turbulence were found to yield somewhat better predictions. According to the performed measurements, the magnitude of one hour single-sided open-door airing in a church typically yields around 50% air exchange, indicating that this is a workable ventilation method, also for such large building volumes. A practical kind of diagram to facilitate estimation of suitable airing period is presented. The ability of the IDA Indoor Climate and Energy (IDA-ICE) computer program to predict airing rates was examined by comparing with field measurements in a church. The programs’ predictions of single-sided airflows through an open door of the church were of the same magnitude as the measured ones; however, the effect of wind direction was not well captured by the program, indicating a development potential. Finally, wind driven air flows through porch type openings of a church model were studied in a wind tunnel, where the airing rates were measured by tracer gas. At single-sided airing, a higher flow rate was observed at higher wind turbulence and when the opening was on the windward side of the building, in agreement with field measurements. Further, the airing rate was on the order of 15 times higher at cross flow than at single-sided airing. Realization of cross flow thus seems highly recommendable for enhanced airing. Calibration constants for a simple equation for wind driven flow through porches are presented. The measurements also indicate that advection through turbulence is a more important airing mechanism than pumping. The present work adds knowledge particularly to the issues of air infiltration and airing through doors, in large single zones. The results can be applicable also to other kinds of large single-zone buildings, like industry halls, atriums and sports halls.Naturlig ventilation är den dominerande ventilationsprocessen i äldre byggnader såsom kyrkor, och även i de flesta småhus i Sverige och övriga delar av världen. Luftinfiltration och vädring utgör viktiga komponenter i naturlig ventilation, där luftinfiltration är luftflöde genom oavsiktliga läckage i byggnadsskalet, medan vädring är avsiktligt luftutbyte genom stora öppningar såsom fönster och dörrar/portar. Vädring kan i sin tur ske ensidigt (genom en öppning) eller som tvärdrag (genom två eller flera öppningar belägna på olika ytterväggar). Det totala luftutbytet påverkar värmeförluster och inomhusluftens kvalité. I kyrkor orsakar avsättning av luftpartiklar en gradvis nedsmutsning av invändiga ytor, inklusive väggmålningar och andra konstföremål. Betydande mängder partiklar avges från besökare, tända ljus, rökelse, o.d. Tillfällig vädring kan minska detta problem, men även användas för att justera innetemperaturen. Föreliggande studie analyserar mekanismer och predikteringsmodeller gällande luftinfiltration och dörrvädring genom fältmätningar, vindtunnelförsök och datorsimuleringar. Luftinfiltration och vädring har samma drivkrafter, d.v.s. vind och termik (inne‑ute temperaturskillnader). Båda dessa drivkrafter är svåra att predicera, särskilt vindinducerade flöden och kombinationen av termik och vind. Två av de mest etablerade modellerna för luftinfiltrationsprediktering i byggnader har utvärderats via mätningar i tre kulturhistoriska stenkyrkor i Sverige. En korrigeringsfaktor av 0,8 föreslås för bättre prediktion av den ena modellen (som gav bäst resultat) gällande höga en-zonsbyggnader såsom kyrkor. En detaljerad numerisk modell är utvecklad för luftinfiltrationsprediktering, där indata baseras på fältundersökningar, inkl. IR-termografering och uppmätt av neutrala tryckplanet (NPL). Modellens funktionalitet har validerats via mätningar i en av fallstudierna och pekar på tämligen god prediktionsprestanda. Vidare utveckling av modellen föreslås, inkl. ett mer systematiskt kalibreringssystem, för olika typer av byggnader och väderförhållanden. Gällande vädring mättes både ensidigt flöde och tvärdrag genom portar i olika kyrkobyggnader med hjälp av spårgas samt direkta lufthastighetsmätningar i portöppning. Mätresultaten jämfördes med erhållna prediktioner från fyra tidigare utvecklade modeller för ensidig ventilation. De modeller som tog hänsyn till vindturbulens gav något bättre resultat. Enligt utförda mätningar medför en timmes ensidig portvädring i en kyrka cirka 50 % luftutbyte, vilket indikerar att detta är en tillämpbar ventilationsmetod, även för så pass stora byggnadsvolymer. Ett särskilt vädringsdiagram presenteras, som syftar till att underlätta uppskattning av erforderlig vädringsperiod. Vidare studerades predikteringsprestanda hos IDA Indoor Climate and Energy (IDA-ICE) simuleringsprogram avseende vädring, där simuleringsdata jämfördes med fältmätningar i en kyrka. Programmets prediktion av ensidigt luftflöde genom en öppen kyrkport var av samma storlekordning som det uppmäta; dock klarade programmet inte av att hantera inverkan av vindriktning så väl, vilket pekar på en utvecklingspotential. Avslutningsvis undersöktes vinddrivet flöde igenom portöppningar i en kyrkmodell i vindtunnel, där luftomsättningen mättes med hjälp av spårgasmetoden. Vid ensidig vädring observerades högre flöde vid högre vindturbulens och när öppningen var på vindsidan av byggnaden, i överensstämmelse med fältmätningarna. Dessutom var vädringsflödet vid tvärdrag i storleksordningen 15 högre än det vid ensidig vädring. Det verkar alltså som att man kan öka vädringstakten avsevärt om man kan åstadkomma tvärdrag. Kalibreringskonstanter presenteras också för en enkel ekvation för vinddrivet flöde genom portar. Vindtunnelstudien indikerar vidare att advektion genom turbulens är en viktigare vädringsmekanism än pumpning. Föreliggande arbete bidrar med kunskap speciellt kring luftinfiltration och vädring genom portar i höga en-zonsbyggnader. Resultaten kan även vara tillämpliga på andra typer av höga en-zonsbyggnader såsom industrihallar, atrier/ljusgårdar och idrottshallar.
Church project
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Alves, Pedro Jorge Ferreira. "Low Reynolds Number Propeller Performance Measurement in Wind Tunnel Test Rig." Master's thesis, 2014. http://hdl.handle.net/10400.6/6454.
Full textAbstract:
The objective of the work in this thesis was to to equip the University’s of Beira Interior wind
tunnel with a Low Reynolds Number (LRN) Propeller Performance Test Rig. This LRN condition
is veri ed in small Unmanned Aerial Vehicles (UAVs) applications or in the high-altitude
airships covered by the project MAAT-Multybody Advanced Airship for Transport. The design,
construction and validation of an accurate measuring mechanism was conducted. The test rig
was developed to collect performance data of propellers with diameter between 6 to 14 inches
(approx. 0.15 to 0.40m), operating at Reynolds number between 30,000 to 300,000 (based on
chord at 3=4 of the blade radius). The design chosen for the thrust balance closely resembles
the T-shaped pendulum structure originally built in the University of Illinois at Urbana-Champaign
(UIUC). Due to the adjustable load cell positioning, this setting allows the use of the
full range of the load cell for most thrust levels in the propeller size, relative wind speed and
rotation speed ranges.
The test rig was completely validated and the experimental procedure was shown herein as
well. Furthermore, thrust and torque characteristics of two Aeronaut Carbon Electric were measured.
It was shown that as the Reynolds number increases with the increase of propeller RPM,
it affects the propellers performance increasing their thrust coef cient and their ef ciency.
The developed test rig can be used for several purposes, namely: the design of propellers in
the UBI’s Department of Aerospace Sciences; the development UAVs, as well as the validation
and improvement of numerical tools such as JBLADE.O objetivo do trabalho levado a cabo nesta tese foi dotar o túnel de vento da Universidade da Beira Interior de um equipamento de medição de desempenho de hélices de baixo número de Reynolds. Esta condição veri ca-se em casos da aplicação em pequenos Veículos Aéreos Não Tripulados (VANTs) ou aeronaves que operem a grande altitude, como é o caso dos dirigíveis no projeto MAAT-Multybody Advanced Airship for Transport. O sistema de medição foi desenvolvido para recolher dados de desempenho de hélices com um diâmetro compreendido entre 6 e 14 polegadas (aprox. 0,15 a 0,40 m), operando num número de Reynolds compreendido entre 30.000 a 300.000 (baseado na corda a 3=4 do raio da pá). O conceito escolhido para a estrutura da balança desenvolvida para a medição da tração, consiste num pêndulo em forma de T que se assemelha ao originalmente construído na Universidade de Illinois em Urbana-Champaign (UIUC). Devido ao posicionamento ajustável de célula de carga, esta con guração permite a utilização de toda a escala da célula de carga para a maioria das condições de funcionamento das hélices propostas. A conceção, construção e validação de todo o mecanismo e procedimentos de medição são apresentados detalhadamente. Além disso, foi medido o desempenho de duas hélices da gama CAM Carbon do fabricante Aeronaut, a de duas pás 13x8 e a de três pás 12x8 . Foi demonstrado que, o aumento do número de Reynolds associado ao aumento das RPM, tem uma in uência considerável no desempenho das hélices, aumentando a sua e - ciência e coe ciente de tração. A instalação experimental desenvolvida pode ser utilizada para diversos ns, nomeadamente: o projeto de hélices no seio do Departamento de Ciências Aeroespaciais da UBI; para os trabalhos de desenvolvimento de VANTs, bem como para a validação e aperfeiçoamento de ferramentas numéricas como é o JBLADE.
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Abdelrahman, Ahmed. "Development of a Wind Turbine Test Rig and Rotor for Trailing Edge Flap Investigation." Thesis, 2014. http://hdl.handle.net/10012/8454.
Full textAbstract:
Alleviating loads on a wind turbine blades would allow a reduction in weight, and potentially increase the size and lifespan of rotors. Trailing edge flaps are one technology proposed for changing the aerodynamic characteristics of a blade in order to limit the transformation of freestream wind fluctuations into load fluctuations within the blade structure. An instrumented wind turbine test rig and rotor were developed to enable a wide-range of experimental set-ups for such investigations. The capability of the developed system was demonstrated through a study of the effect of stationary trailing edge flaps on blade load and performance. The investigation focused on measuring the changes in flapwise bending moment and power production for various trailing edge flap parameters. The blade was designed to allow accurate instrumentation and customizable settings, with a design point within the range of wind velocities in a large open jet test facility. The wind facility was an open circuit wind tunnel with a maximum velocity of 11m/s in the test area. The load changes within the blade structure for different wind speeds were measured using strain gauges as a function of flap length, location and deflection angle. The blade was based on the S833 airfoil and is 1.7 meters long, had a constant 178mm chord and a 6o pitch. The aerodynamic parts were 3D printed using plastic PC-ABS material. The total loading on the blade showed higher reduction when the flap was placed further away from the hub and when the flap angle (pitching towards suction side) was higher. The relationship between the load reduction and deflection angle was roughly linear as expected from theory. The effect on moment was greater than power production with a reduction in moment up to 30% for the maximum deflection angle compared to 6.5% reduction in power for the same angle. Overall, the experimental setup proved to be effective in measuring small changes in flapwise bending moment within the wind turbine blade.
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Khorsand, Asgari Iman. "Instrumentation, Control, and Testing of a Small Wind Turbine Test Rig." Thesis, 2015. http://hdl.handle.net/1828/6060.
Full textAbstract:
As a cost-effective test method, a vehicle-based test rig can be utilized in small wind turbine experimental work to facilitate turbine performance tests under a range of controlled wind speeds, as well as to validate turbulent flow models. The instrumentation of a custom trailer-based mobile wind turbine test rig has been modified to provide a platform for full rotor speed control. A control system coupled to an electric vehicle controller with regenerative braking technology was developed in five steps, namely: system modeling in Simulink, system identification, control system design and analysis, control system implementation in LabVIEW, and Proportional-Integral-Derivative (PID) controller tuning in real-time. A custom Graphical User Interface (GUI) was also developed. Furthermore, a Computational Fluid Dynamics (CFD) analysis was conducted to assess the potential impact of towing vehicle’s disturbance on the free stream available to the rotor disc. This trailer rig will allow up to a 1kW wind turbine. It can be towed behind a vehicle to conduct steady state tests or it can be parked in an open area to collect unsteady field data. It has been tested in a towed scenario and the Blade Element Momentum (BEM) predictions were compared with the obtained aggregate performance curve.Graduate
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khorsand@uvic.ca
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McWilliam, Michael Kenneth. "Development of a Wind Tunnel Test Apparatus for Horizontal Axis Wind Turbine Rotor Testing." Thesis, 2008. http://hdl.handle.net/10012/4075.
Full textAbstract:
Currently, wind energy presents an excellent opportunity to satisfy the growing demand without the supply and environmental problems associated with conventional energy. The engineering in wind turbines is not fully mature. There are still phenomenon, particularly dynamic stall, that cannot accurately be modeled or controlled. Dynamic stall contributes to fatigue stress and premature failure in many turbine components. The three dimensionality of dynamic stall makes these structures unique for wind turbines. Currently, flow visualization of dynamic stall on a wind turbine rotor has not been achieved. These visualizations can reveal a lot about the structures that contribute to dynamic stall.
Particle Image Velocimetry (PIV) is a powerful experimental technique that can take multiple non-intrusive flow measurements simultaneously of planar flow. Using high-speed cameras time resolved PIV can reveal the transient development of a given flow field. This technique is ideally suited to gain a better understanding of dynamic stall. A custom wind turbine is being built at the University of Waterloo to allow such measurements on the blade. A high speed camera is mounted on the hub and will take measurements within the rotating domain. Mirrors are used so that laser illumination rotates with the blade. The wind turbine will operate in controlled conditions provided by a large wind tunnel. High speed pressure data acquisition will be used in conjunction with PIV to get an understanding of the forces associated with the flow structures. Computational fluid dynamics was used to size the rotor within the wind tunnel. Laser based measurements required special considerations for stiffness.
Many revealing experiments will be made possible by this apparatus. First, the flow structures responsible for the various forces can be identified. Quantitative measurements of the flow field will identify the development of the stall vortex. The quantified flow structures can be used verify and improve models. The high spatial resolution of PIV can map the three dimensional flow structure in great detail. The experimental apparatus is independent of the blade geometry, as such multiple blades can be used to identify the effect of blade geometry. Finally flow control research in the field of aviation can be applied to control dynamic stall.