Infrared transition location estimates can be fast and useful measurements in wind tunnel and flight tests. Because turbulent boundary layers have a much higher rate of convective heat transfer than laminar boundary layers, a difference in surface temperature can be observed between turbulent and laminar regions of an airfoil at a different temperature than the free stream air temperature. Various implementations of this technique are examined in a wind tunnel. These include using a heat lamp as an external source and circulating fluid inside of the airfoil. Furthermore, ABS plastic and aluminum airfoils are tested with and without coatings such as black paint and surface wraps. The results show that thermal conduction within the model and surface reflections are the driving issues in designing an IR system for detecting transition. Aluminum has a high thermal diffusivity so is a poor choice for this method. However, its performance can be improved using an insulating layer. Internal fluid circulation was far more successful than the heat lamp because it eliminates the reflected IR due to the heat lamp. However, using smooth surface wraps can mitigate reflection issues caused by the heat lamps by reducing the scatter within the reflection, producing an IR image with fewer contaminating reflections.

In recent years, especially in the crowded city-centers where land prizes have become extremely high, tall buildings with more than 30 floors have started to be designed and constructed in Turkey. On the other hand, the technical improvements have provided the opportunity of design and construction of more slender structures which are influenced by the wind actions more. If the building is flexible, wind can interact with it so the wind induced oscillations can be significantly magnified. In order to analyze the response of such buildings under wind effects, wind tunnel tests are accepted to be the most powerful tool all over the world. In this study, a series of tests were performed in Ankara Wind Tunnel on a model building in the shape of a rectangular prism. For the similitude of flow conditions, passive devices were designed. The response of the model building was measured through a high frequency base balance which was designed specifically for this case study. Through the tests, the effects of turbulence intensity, vortex shedding and wind angle of attack on the response of the building were questioned. Finally, the results were compared with the results of various technical specifications about wind.

The unsteady interaction between trailing edge aerodynamic flow control and airfoil motion in pitch and plunge is investigated in wind tunnel experiments using a two degree-of-freedom traverse which enables application of time-dependent external torque and forces by servo motors. The global aerodynamic forces and moments are regulated by controlling vorticity generation and accumulation near the trailing edge of the airfoil using hybrid synthetic jet actuators. The dynamic coupling between the actuation and the time-dependent flow field is characterized using simultaneous force and particle image velocimetry (PIV) measurements that are taken phase-locked to the commanded actuation waveform. The effect of the unsteady motion on the model-embedded flow control is assessed in both trajectory tracking and disturbance rejection maneuvers. The time-varying aerodynamic lift and pitching moment are estimated from a PIV wake survey using a reduced order model based on classical unsteady aerodynamic theory. These measurements suggest that the entire flow over the airfoil readjusts within 2-3 convective time scales, which is about two orders of magnitude shorter than the characteristic time associated with the controlled maneuver of the wind tunnel model. This illustrates that flow-control actuation can be typically effected on time scales that are commensurate with the flow's convective time scale, and that the maneuver response is primarily limited by the inertia of the platform.

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.

Accurate prediction of performance is an important aspect of modern sailing yacht design and provides a competitive advantage on the racecourse and in the marketplace. Although wind tunnel testing of yacht sails is a common tool for obtaining input data for Velocity Prediction Programs, its results have not been validated against aerodynamic full-scale measurements as quality full-scale data is rare. Wind tunnel measurements are conducted at the Twisted Flow Wind Tunnel of The University of Auckland and are compared to the full-scale aerodynamic force measurements from the Berlin Sail-Force-Dynamometer. To realise this comparison wind tunnel techniques and aerodynamic force models for yacht sails are enhanced; this in turn also improves the accuracy of Velocity Prediction Programs. Force and surface pressure measurements were conducted demonstrating that the interaction of the hull/deck with the sails has a significant effect on the side force and the force perpendicular to the deck plane, and that this should be considered in aerodynamic analysis of sails and the performance prediction of yachts. The first Real-Time Velocity Prediction Program for wind tunnel testing has been developed and implemented as an additional module of FRIENDSHIP-Equilibrium. Model sails can now be trimmed based on the full-scale performance of the yacht, and at the correct heel angle, which makes the trimming process in the wind tunnel much more similar to the real life situation. Improved aerodynamic force models have been developed from realistically depowered sail trims obtained with the Real-Time Velocity Prediction Program. An empirical model that describes the force and moment changes due to depowering in detail has been developed and implemented. The standard semi-empirical trim parameter model, which expresses depowering in a more generic way, has been enhanced based on aerodynamic principles and validated against the wind tunnel results. Utilising the enhanced wind tunnel techniques and aerodynamic force models, a generally good qualitative and quantitative agreement with the full-scale data is achieved. Remaining challenges associated with full-scale and wind tunnel tests are however also highlighted and, based on this work alone, a conclusive judgement that scaling effects are negligible cannot be made. / Whole document restricted, but available by request, use the feedback form to request access. / IPENZ Craven Scholarship; The University of Auckland Yacht Research Unit Scholarship; The University of Auckland Graduate Research Fund

Accurate prediction of performance is an important aspect of modern sailing yacht design and provides a competitive advantage on the racecourse and in the marketplace. Although wind tunnel testing of yacht sails is a common tool for obtaining input data for Velocity Prediction Programs, its results have not been validated against aerodynamic full-scale measurements as quality full-scale data is rare. Wind tunnel measurements are conducted at the Twisted Flow Wind Tunnel of The University of Auckland and are compared to the full-scale aerodynamic force measurements from the Berlin Sail-Force-Dynamometer. To realise this comparison wind tunnel techniques and aerodynamic force models for yacht sails are enhanced; this in turn also improves the accuracy of Velocity Prediction Programs. Force and surface pressure measurements were conducted demonstrating that the interaction of the hull/deck with the sails has a significant effect on the side force and the force perpendicular to the deck plane, and that this should be considered in aerodynamic analysis of sails and the performance prediction of yachts. The first Real-Time Velocity Prediction Program for wind tunnel testing has been developed and implemented as an additional module of FRIENDSHIP-Equilibrium. Model sails can now be trimmed based on the full-scale performance of the yacht, and at the correct heel angle, which makes the trimming process in the wind tunnel much more similar to the real life situation. Improved aerodynamic force models have been developed from realistically depowered sail trims obtained with the Real-Time Velocity Prediction Program. An empirical model that describes the force and moment changes due to depowering in detail has been developed and implemented. The standard semi-empirical trim parameter model, which expresses depowering in a more generic way, has been enhanced based on aerodynamic principles and validated against the wind tunnel results. Utilising the enhanced wind tunnel techniques and aerodynamic force models, a generally good qualitative and quantitative agreement with the full-scale data is achieved. Remaining challenges associated with full-scale and wind tunnel tests are however also highlighted and, based on this work alone, a conclusive judgement that scaling effects are negligible cannot be made. / Whole document restricted, but available by request, use the feedback form to request access. / IPENZ Craven Scholarship; The University of Auckland Yacht Research Unit Scholarship; The University of Auckland Graduate Research Fund

Accurate prediction of performance is an important aspect of modern sailing yacht design and provides a competitive advantage on the racecourse and in the marketplace. Although wind tunnel testing of yacht sails is a common tool for obtaining input data for Velocity Prediction Programs, its results have not been validated against aerodynamic full-scale measurements as quality full-scale data is rare. Wind tunnel measurements are conducted at the Twisted Flow Wind Tunnel of The University of Auckland and are compared to the full-scale aerodynamic force measurements from the Berlin Sail-Force-Dynamometer. To realise this comparison wind tunnel techniques and aerodynamic force models for yacht sails are enhanced; this in turn also improves the accuracy of Velocity Prediction Programs. Force and surface pressure measurements were conducted demonstrating that the interaction of the hull/deck with the sails has a significant effect on the side force and the force perpendicular to the deck plane, and that this should be considered in aerodynamic analysis of sails and the performance prediction of yachts. The first Real-Time Velocity Prediction Program for wind tunnel testing has been developed and implemented as an additional module of FRIENDSHIP-Equilibrium. Model sails can now be trimmed based on the full-scale performance of the yacht, and at the correct heel angle, which makes the trimming process in the wind tunnel much more similar to the real life situation. Improved aerodynamic force models have been developed from realistically depowered sail trims obtained with the Real-Time Velocity Prediction Program. An empirical model that describes the force and moment changes due to depowering in detail has been developed and implemented. The standard semi-empirical trim parameter model, which expresses depowering in a more generic way, has been enhanced based on aerodynamic principles and validated against the wind tunnel results. Utilising the enhanced wind tunnel techniques and aerodynamic force models, a generally good qualitative and quantitative agreement with the full-scale data is achieved. Remaining challenges associated with full-scale and wind tunnel tests are however also highlighted and, based on this work alone, a conclusive judgement that scaling effects are negligible cannot be made. / Whole document restricted, but available by request, use the feedback form to request access. / IPENZ Craven Scholarship; The University of Auckland Yacht Research Unit Scholarship; The University of Auckland Graduate Research Fund

Accurate prediction of performance is an important aspect of modern sailing yacht design and provides a competitive advantage on the racecourse and in the marketplace. Although wind tunnel testing of yacht sails is a common tool for obtaining input data for Velocity Prediction Programs, its results have not been validated against aerodynamic full-scale measurements as quality full-scale data is rare. Wind tunnel measurements are conducted at the Twisted Flow Wind Tunnel of The University of Auckland and are compared to the full-scale aerodynamic force measurements from the Berlin Sail-Force-Dynamometer. To realise this comparison wind tunnel techniques and aerodynamic force models for yacht sails are enhanced; this in turn also improves the accuracy of Velocity Prediction Programs. Force and surface pressure measurements were conducted demonstrating that the interaction of the hull/deck with the sails has a significant effect on the side force and the force perpendicular to the deck plane, and that this should be considered in aerodynamic analysis of sails and the performance prediction of yachts. The first Real-Time Velocity Prediction Program for wind tunnel testing has been developed and implemented as an additional module of FRIENDSHIP-Equilibrium. Model sails can now be trimmed based on the full-scale performance of the yacht, and at the correct heel angle, which makes the trimming process in the wind tunnel much more similar to the real life situation. Improved aerodynamic force models have been developed from realistically depowered sail trims obtained with the Real-Time Velocity Prediction Program. An empirical model that describes the force and moment changes due to depowering in detail has been developed and implemented. The standard semi-empirical trim parameter model, which expresses depowering in a more generic way, has been enhanced based on aerodynamic principles and validated against the wind tunnel results. Utilising the enhanced wind tunnel techniques and aerodynamic force models, a generally good qualitative and quantitative agreement with the full-scale data is achieved. Remaining challenges associated with full-scale and wind tunnel tests are however also highlighted and, based on this work alone, a conclusive judgement that scaling effects are negligible cannot be made. / Whole document restricted, but available by request, use the feedback form to request access. / IPENZ Craven Scholarship; The University of Auckland Yacht Research Unit Scholarship; The University of Auckland Graduate Research Fund

Desde o início da década de 2010, o aumento do preço do combustível de aviação e a pressão da sociedade para redução da emissão de gases nocivos ao meio ambiente, junto com a necessidade de redução de ruído durante as fases de decolagem e pouso, levaram as companhias aéreas a buscar aeronaves mais eficientes. Para suprir essa demanda, os fabricantes de aviões comerciais solucionaram esse problema através do uso de motores de maior desempenho, que apresentam maior diâmetro que motores de gerações passadas. Desse modo, foi necessário projetar asas com maior diedro na região da raiz, possibilitando a instalação desses novos motores, e diedro menor após a seção do motor, adotando assim a solução de asa em gaivota. O presente trabalho visa analisar o impacto de diferentes tipos de asas em gaivota nos coeficientes aerodinâmicos de uma aeronave de configuração comercial típica. Para tanto, foi realizada uma revisão bibliográfica dos estudos envolvendo asas em gaivota. Numa primeira fase foi feito um estudo analítico das características aerodinâmicas de alguns modelos de aeronaves com asa em gaivota, e em uma segunda fase, foram empregadas ferramentas computacionais para analisar seus comportamentos aerodinâmicos. Posteriormente, em uma terceira fase, esses modelos foram ensaiados no túnel de vento do LAE (Laboratório de Aerodinâmica da EESC/USP), e os resultados das três fases foram comparados. / Since the beginning of the 2010s, the increasing price of aviation fuel and the pressure of society to reduce the emission of harmful gases into the environment, coupled with the need of noise reduction during the takeoff and landing, induce carrier companies to look for more efficient airplanes. To furnish this demand, the airplane manufacturers solved the problem using high performance engines, which present a larger diameter than the engines from previous generations. Thereby, it was necessary to project wing with higher dihedral on the root portion, enabling the installation of these new engines, and a lower dihedral after the engine section, thus adopting a gull wing solution. This research project aims at analyzing the impact of different types of gull wing on the aerodynamic coefficients of a typical commercial configuration airplane. For this purpose, a bibliographic review about the studies related to gull wings was performed. In a first phase, an analytical analysis of the aerodynamic characteristics of some airplane model with gull wings was done, and in a second phase, computational programs was used to study their aerodynamic behavior. Later, in a third phase, these models were tested in the wind tunnel of LAE (Laboratory of Aerodynamics of EESC/USP), and the results from the three phases were compared.

Depuis plusieurs décennies, le trafic aérien ne cesse de croître. Ainsi, près de 6 milliards de passagers transitent dans le monde par an. Les objectifs européens à l’horizon 2020 en terme d’émission sonore des aéronefs imposent une réduction de 10 dB par point de mesure par rapport aux aéronefs de l’an 2000. Dans ce contexte, le projet européen VALIANT (VALidation and Improvement of Airframe Noise prediction Tools) a pour but principal de tester, valider et améliorer les codes numériques et les modèles de prédiction du bruit de cellule (trains d’atterrissage + voilure) sur des géométries simplifiées afin de disposer de cas tests pour les recherches futures. L’objectif de la thèse, associé à la contribution de l’ECL dans ce projet, est de créer des bases de données expérimentales fiables sur des systèmes à deux éléments – bec/aile et aile/volet – et de modéliser analytiquement le bruit issu de tels systèmes. La thèse s’est concentrée sur un système aile/volet non porteur et parallèle dans un écoulement de soufflerie à veine ouverte, en configuration d’alignement ou de recouvrement partiel, menant à de possibles interactions aérodynamiques et/ou acoustiques. Les mesures ont été faites pour différentes vitesses d’écoulement (30 − 100 m~s), avec une attention particulière à 50 m~s (M0 ∼ 0, 15). Le taux de turbulence de l’écoulement incident est modifiable par l’ajout d’une grille de turbulence à maille large placée dans la section de sortie du convergent. Les résultats aérodynamiques (fil chaud, pression en paroi) ont révélé la présence d’une forte interaction lorsque la distance entre les deux corps est de l’ordre de grandeur de la couche limite turbulente au bord de fuite de l’aile. De plus, le couplage acoustique a lieu lorsque la longueur de recouvrement est positive ou nulle. Des mesures de localisation de sources menées par l’ONERA/DSNA ont permis de valider les mesures de champ lointain en confirmant l’absence de sources de bruit d’installation en dessous de 10 kHz. Par ailleurs, des comparaisons avec les simulations numériques donnent de bons accords. Du point de vue analytique, le problème mathématique de deux plaques planes en recouvrement partiel dans un écoulement uniforme a été posé et une réduction bidimensionnelle a été justifiée. Le problème n’ayant pas de solution exacte, plusieurs modèles issus de la littérature – théories de Howe et d’Amiet – ont été étudiés. Les plus pertinents ont été confrontés aux résultats expérimentaux, révélant les limites asymptotiques de ces modèles. Un modèle original est alors proposé pour la géométrie du problème posé, sans hypothèse restrictive. La démarche est basée sur une procédure de diffraction itérative permettant de prendre en compte la proximité des deux corps et utilisant la fonction de Green exacte du demi-plan en écoulement uniforme. Le modèle prédit des comportements qualitatifs angle/fréquence proches des résultats expérimentaux. La prise en compte de la statistique des rafales incidentes reste néanmoins à effectuer afin de procéder à des comparaisons quantitatives. Une campagne expérimentale complémentaire avec une marche descendante permet de mettre en évidence les écoulements de cavité arrière d’une aile, plus proche de la réalité. De même, des mesures sur une configuration bec/aile a été testée et la prise en compte de la déflexion du jet de la soufflerie pour la réfraction des ondes sonores par la couche de cisaillement a été proposée. / Air traffic still grows from decades, with yearly 6 billion passengers nowadays in the world. By 2020, the EC imposes aircraft noise reductions by 10 dB per measuring point with respect to the status in 2000. In this context, VALIANT (VALidation and Improvement of Airframe Noise prediction Tools) is an EC-supported project that aims at testing, validating and improving numerical codes and analytical/theoretical models for the prediction of airframe noise (landing gears + high-lift devices) in simplified configurations in order to generate test cases for research needs. The main objective of the thesis in connection with ECL contribution in the scope of VALIANT project is to generate reliable experimental databases for 2-element systems – slatwing and wing-flap – as well as to analytically model overlapping configurations. It is particulary focussed on the experimental and analytical studies of a non lifting wing-flap system in a parallel flow, in aligned and overlapping arrangements. This is aimed at discussing likely aerodynamic and/or acoustic interactions. The tests have been carried out in an open-jet anechoic wind-tunnel for each arrangement and for several flow speeds (30-100 m/s), with main interest on 50 m/s (M0 ∼ 0, 15). The turbulence rate could be changed by fixing a removable turbulence grid with a large mesh at the outlet cross-section of the duct. Aerodynamic results (hot-wire anemometry, wall-pressure) show a strong interaction when the wing-flap distance is about the wing trailingedge boundary layer thickness. Acoustic coupling can be pointed out in cases of overlap. Source localization tests performed by ONERA/DSNA have permitted to validate far-field acoustic tests since no installation effect source seems to strongly radiate below 10 kHz. A good agreement with numerical simulations has been shown for every test. In order to predict noise analytically for a 2-element system in case of overlap in a uniform flow, the mathematical statement has been defined and a 2D-reduction of the equation system can be justified. Since no exact solution exists, several models from the literature – Howe’s and Amiet’s theories – have been studied. Comparisons between overlapping half-planes and slotted trailing-edge models proposed by Howe and experimental results show obvious limitations in the predictions. Then, an original model is proposed involving two bodies in close overlap arrangement, with no assumption. It is based on an iterative scattering procedure to take into account the close vicinity of the two bodies, using the exact half-plane Green’s function in a uniform flow. Convergence is relatively quick and qualitative predictions in angle/frequency behaviour show a good agreement with experiments. However, the statistics of the vortical flows responsible for the sound must be implemented for better comparisons. Other experiments have been done with a backward-facing step – it represents wing trailing-edge cove – to make cavity flow mechanisms appear, such as what is observed in real HLD. Finally, a series of tests has been performed involving a slat-wing system and an angular correction due to refraction of sound waves in shear-layer for a deflected jet has been proposed.