This thesis describes the development of a generic design methodology for variable camber flap systems for transport aircraft, intended to be used for cruise and low-speed operations. The methodology was structured after several revisions were performed on conventional high-lift device design methodologies for existing transport aircraft. The definition and detail explanations are given at every phase of the methodology. A case study was performed in order to give an example of the implementation of the methodology where a transport aircraft called A TRA, a design study from previous PhD report, was taken as a model. Experimental work could not be performed, due to budget constraints, so the case study was only carried out using computer-based analyses. Software packages such as MSES-code (a Computational Fluid Dynamic software), CATIA and PATRANINASTRAN were used for this case study to analyse aerodynamic characteristics, layout as well as simulation and structure analyses respectively. The results obtained showed that it was practically feasible to deploy such a high-lift device to transport aircraft when the effect from aerodynamic loads gave minimum effect on structural deformation. The deflections of the flap as well as spoilers under critical loads were below the allowable limits, which had a minimal effect due to the additional lift force generated from the movable surfaces.

Due to the significant effects on the performance and competitiveness of aircraft, high lift devices are of extreme importance in aircraft design. The flow physics of high lift devices is so complex, that traditional one pass and multi-pass design approaches can’t reach the most optimised concept and multi-objective design optimisation (MDO) methods are increasingly explored in relation to this design task. The accuracy of the optimisation, however, depends on the accuracy of the underlying Computational Fluid Dynamics (CFD) solver. The complexity of the flow around high-lift configuration, namely transition and separation effects leads to a substantial uncertainty associated with CFD results. Particularly, the uncertainty related to the turbulence modelling aspect of the CFD becomes important. Furthermore, employing full viscous flow solvers within MDO puts severe limitations on the density of computational meshes in order to achieve a computationally feasible solution, thereby adding to the uncertainty of the outcome. This thesis explores the effect of uncertainties in CFD modelling when detailed aerodynamic analysis is required in computational design of aircraft configurations. For the purposes of this work, we select the benchmark NLR7301 multi-element airfoil (main wing and flap). This flow around this airfoil features all challenges typical for the high-lift configurations, while at the same time there is a wealth of experimental and computational data available in the literature for this case. A benchmark shape bi-objective optimization problem is formed, by trying to reveal the trade-off between lift and drag coefficients at near stall conditions. Following a detailed validation and grid convergence study, three widely used turbulence models are applied within Reynolds-Averaged Navier-Stokes (RANS) approach. K- Realizable, K- SST and Spalart-Allmaras. The results show that different turbulent models behave differently in the optimisation environment, and yield substantially different optimised shapes, while maintaining the overall optimisation trends (e.g. tendency to maximise camber for the increased lift). The differences between the models however exhibit systemic trends irrespective of the criteria for the selection of the target configuration in the Pareto front. A-posteriori error analysis is also conducted for a wide range of configurations of interest resulting from the optimisation process. Whereas Spalart-Allmaras exhibits best accuracy for the datum airfoil, the overall arrangement of the results obtained with different models in the (Lift, Drag) plane is consistent for all optimisation scenarios leading to increased confidence in the MDO/RANS CFD coupling.

This thesis will describe the works had been done by the author in the Flying Crane aircraft group design project and the new design of a novel swing arm mechanism which can be applied in the trailing edge high lift devices for this aircraft concept. Flying Crane aircraft is a new generation commercial airliner concept as the result of group design project conducted by China Aviation Industry Corporation I (AVIC I) and Cranfield University. At the end of the group design project, parameters such as take-off and landing distance, trailing edge flap type and deflection in take-off and landing configuration of the Flying Crane concept have been determined. These parameters are design input of the novel trailing edge high lift device mechanism for this aircraft concept. The idea of this innovative mechanism comes from the research achievement of a previous MSc student, Thomas Baxter, which applied swing arm mechanism into a passenger aircraft's leading edge slat. This thesis applied this idea to trailing edge flap and modeled the mechanism on CATIA software to yield a kinematic simulation for the purpose of check motion trail and force transfer in this mechanism. Relevant works such as actuation, mass and stress analysis are also involved. As the result of this research project, it was found that swing arm mechanism trends to require relatively small fairings for supports and attachments due to its high stowed space utilizing efficiency. Initial mass estimation carried out in this thesis also indicates that the new design takes advantage in terms of weight comparing with traditional trailing edge flap mechanisms. Thus. swing arm mechanism is supposed to show great competitive potential for commercial airliner's trailing edge flaps after further analysis has been done in the detail design phase.

O presente trabalho refere-se a um estudo aeroacústico experimental visando caracterizar o ruído de eslate sob a presença de excrescências instaladas no interior de sua cova, e em ângulos de ataque extremos (entre -4 e 18 [º]). O eslate é um dispositivo hipersustentador posicionado no bordo de ataque do perfil aerodinâmico que objetiva a operação da aeronave em voo com uma menor velocidade. Desta maneira, é proporcionado um maior ângulo de estol e consequente maior sustentação, permitindo que os procedimentos de pouso e decolagem sejam mais seguros e que uma pista menor para ambas as operações possa ser utilizada, por exemplo. Este estudo contempla um modelo de perfil MDA 30P30N, com as excrescências no formato de selos de seção transversal bidimensional, circular e quadrada, presentes em diferentes posições na cova do eslate e ao longo de toda a sua envergadura. Foram compreendidos diferentes ângulos de ataque do modelo e velocidades de escoamento livre. O trabalho experimental utilizou-se de um túnel de vento de seção de testes e circuito fechados da USP-EESC, o modelo MDA 30P30N pré-existente na universidade e equipamentos de medições acústicas (microfones, sistemas de aquisição de dados e etc.), e de pressão (escâneres, manômetros, etc.). O pós-processamento dos dados aeroacústicos adquiridos nos ensaios realizados é uma etapa que objetiva a caracterização do ruído a partir de espectros de frequência e mapas acústicos, para localização e determinação da intensidade das fontes sonoras. Este processo é efetivado com códigos de beamforming implementados pelo grupo de pesquisa contendo o método de deconvolução DAMAS. A técnica de beamforming é um método para localização e estimativa da amplitude de fontes de ruído utilizando medidas realizadas a partir de uma antena de microfones, baseando-se em um modelo matemático que descreve a propagação de ondas acústicas em um meio com propriedades físicas bem definidas. Estes modelos são simplificados em relação à complexidade dos fenômenos de geração e propagação do som. O cálculo basicamente resolve a contribuição relativa das fontes provindas de diferentes direções no campo sonoro de interesse. O método DAMAS almeja compensar a influência das características da antena de microfones empregada para aquisição dos dados do resultado proveniente do cálculo efetuado com a técnica de beamforming convencional, resolvendo um problema de deconvolução. Os espectros de ruído obtidos neste trabalho apresentam o ruído de eslate bem definido em três componentes principais, que são os múltiplos picos tonais de baixa frequência, banda larga e pico tonal de alta frequência. Para a configuração de referência, sem a presença de selos na cova do eslate, verifica-se que ângulos de ataque extremos, muito baixos ou muito altos, apresentam o espectro de frequências quase que inteiramente como de banda larga e de intensidade muito próxima ao ruído de fundo do túnel. Também há um ângulo de ataque em que a emissão sonora é máxima. Quando há a presença de um selo na cova do eslate, existe um grande impacto em seu espectro acústico. Dependo da posição em que o selo se encontra, este pode atenuar ou intensificar os múltiplos picos tonais de baixa frequência, trocar o pico dominante, suprimir a componente de múltiplos picos, modificar o comportamento da componente da banda larga e ainda amplificar ou reduzir o ruído global do eslate. / The present work refers to an experimental aeroacoustic study aiming to characterize slat noise over the presence of excrescences installed at the interior of its cove, and at very high and very low angles of attack (between -4 e 18 [º]). A slat is a high-lift device located at the leading edge of an airfoil which target to maintain the aircraft in flight at a lower speed by providing a greater stall angle and consequently greater lift coefficient, allowing safer landing and take-off procedures. Therefore, a smaller airport runaway for both operations may be used. This study includes a model of a MDA 30P30N airfoil, with a seal excrescence of two-dimensional cross-section shape, circular or square, positioned at different locations at slat cove throughout the extent of its span. Different models angles of attack and some free-stream velocities were tested. The experimental work employed a closed-section wind tunnel situated at USP-EESC, a preexisting MDA 30P30N model, and acoustic measurement equipments (microphones, data acquisition systems, etc.), and pressure measurement equipments (scanners, pressure gauges, etc.). The data post-processing of aeroacoustics experiments intend to characterize the slat noise due to frequency spectrums and acoustic maps to locate and evaluate the intensity of the noise sources. This process is made with beamforming in-house codes, implemented by the research group, containing a deconvolution method named DAMAS. Beamforming technique is a method to localize and assess noise sources amplitude using measurements from an antenna of microphones, based on a mathematical model that describes the propagation of acoustic waves in a medium with well defined physical properties. Such models are simplified compared to the complexity of the phenomena of generation and propagation of sound. The calculation basically resolves the relative contribution of sources emanating from different directions at the sound field of interest. DAMAS method aim to extract the characteristics of the microphones antenna employed to acquire data, from the result of the calculation performed with conventional beamforming algorithm, solving a deconvolution problem. The noise spectrum obtained at this work shows that the slat noise can be well defined in three main components, which are the multiple tonal peaks of low frequency, broadband and high-frequency tonal peak. For the baseline configuration, without seals at slat cove, it is possible to notice that for extreme angles of attack, very low or very high, the noise spectrum is almost entire of broadband type. Its noise intensity is very near to the background wind tunnel noise. There is an angle of attack which has a maximum sound emission. A seal at MDA 30P30N slat cove has a huge impact on slat noise spectrum. Depending on the seal position, it can mitigate or enhance the multiple low-frequency tonal peaks, change the dominant peak, suppress multiple tonal peaks, modify the behavior of the broadband component and reduce or amplify the overall slat noise.

O presente trabalho refere-se a um estudo aeroacústico experimental visando caracterizar o ruído de eslate sob a presença de excrescências instaladas no interior de sua cova, e em ângulos de ataque extremos (entre -4 e 18 [º]). O eslate é um dispositivo hipersustentador posicionado no bordo de ataque do perfil aerodinâmico que objetiva a operação da aeronave em voo com uma menor velocidade. Desta maneira, é proporcionado um maior ângulo de estol e consequente maior sustentação, permitindo que os procedimentos de pouso e decolagem sejam mais seguros e que uma pista menor para ambas as operações possa ser utilizada, por exemplo. Este estudo contempla um modelo de perfil MDA 30P30N, com as excrescências no formato de selos de seção transversal bidimensional, circular e quadrada, presentes em diferentes posições na cova do eslate e ao longo de toda a sua envergadura. Foram compreendidos diferentes ângulos de ataque do modelo e velocidades de escoamento livre. O trabalho experimental utilizou-se de um túnel de vento de seção de testes e circuito fechados da USP-EESC, o modelo MDA 30P30N pré-existente na universidade e equipamentos de medições acústicas (microfones, sistemas de aquisição de dados e etc.), e de pressão (escâneres, manômetros, etc.). O pós-processamento dos dados aeroacústicos adquiridos nos ensaios realizados é uma etapa que objetiva a caracterização do ruído a partir de espectros de frequência e mapas acústicos, para localização e determinação da intensidade das fontes sonoras. Este processo é efetivado com códigos de beamforming implementados pelo grupo de pesquisa contendo o método de deconvolução DAMAS. A técnica de beamforming é um método para localização e estimativa da amplitude de fontes de ruído utilizando medidas realizadas a partir de uma antena de microfones, baseando-se em um modelo matemático que descreve a propagação de ondas acústicas em um meio com propriedades físicas bem definidas. Estes modelos são simplificados em relação à complexidade dos fenômenos de geração e propagação do som. O cálculo basicamente resolve a contribuição relativa das fontes provindas de diferentes direções no campo sonoro de interesse. O método DAMAS almeja compensar a influência das características da antena de microfones empregada para aquisição dos dados do resultado proveniente do cálculo efetuado com a técnica de beamforming convencional, resolvendo um problema de deconvolução. Os espectros de ruído obtidos neste trabalho apresentam o ruído de eslate bem definido em três componentes principais, que são os múltiplos picos tonais de baixa frequência, banda larga e pico tonal de alta frequência. Para a configuração de referência, sem a presença de selos na cova do eslate, verifica-se que ângulos de ataque extremos, muito baixos ou muito altos, apresentam o espectro de frequências quase que inteiramente como de banda larga e de intensidade muito próxima ao ruído de fundo do túnel. Também há um ângulo de ataque em que a emissão sonora é máxima. Quando há a presença de um selo na cova do eslate, existe um grande impacto em seu espectro acústico. Dependo da posição em que o selo se encontra, este pode atenuar ou intensificar os múltiplos picos tonais de baixa frequência, trocar o pico dominante, suprimir a componente de múltiplos picos, modificar o comportamento da componente da banda larga e ainda amplificar ou reduzir o ruído global do eslate. / The present work refers to an experimental aeroacoustic study aiming to characterize slat noise over the presence of excrescences installed at the interior of its cove, and at very high and very low angles of attack (between -4 e 18 [º]). A slat is a high-lift device located at the leading edge of an airfoil which target to maintain the aircraft in flight at a lower speed by providing a greater stall angle and consequently greater lift coefficient, allowing safer landing and take-off procedures. Therefore, a smaller airport runaway for both operations may be used. This study includes a model of a MDA 30P30N airfoil, with a seal excrescence of two-dimensional cross-section shape, circular or square, positioned at different locations at slat cove throughout the extent of its span. Different models angles of attack and some free-stream velocities were tested. The experimental work employed a closed-section wind tunnel situated at USP-EESC, a preexisting MDA 30P30N model, and acoustic measurement equipments (microphones, data acquisition systems, etc.), and pressure measurement equipments (scanners, pressure gauges, etc.). The data post-processing of aeroacoustics experiments intend to characterize the slat noise due to frequency spectrums and acoustic maps to locate and evaluate the intensity of the noise sources. This process is made with beamforming in-house codes, implemented by the research group, containing a deconvolution method named DAMAS. Beamforming technique is a method to localize and assess noise sources amplitude using measurements from an antenna of microphones, based on a mathematical model that describes the propagation of acoustic waves in a medium with well defined physical properties. Such models are simplified compared to the complexity of the phenomena of generation and propagation of sound. The calculation basically resolves the relative contribution of sources emanating from different directions at the sound field of interest. DAMAS method aim to extract the characteristics of the microphones antenna employed to acquire data, from the result of the calculation performed with conventional beamforming algorithm, solving a deconvolution problem. The noise spectrum obtained at this work shows that the slat noise can be well defined in three main components, which are the multiple tonal peaks of low frequency, broadband and high-frequency tonal peak. For the baseline configuration, without seals at slat cove, it is possible to notice that for extreme angles of attack, very low or very high, the noise spectrum is almost entire of broadband type. Its noise intensity is very near to the background wind tunnel noise. There is an angle of attack which has a maximum sound emission. A seal at MDA 30P30N slat cove has a huge impact on slat noise spectrum. Depending on the seal position, it can mitigate or enhance the multiple low-frequency tonal peaks, change the dominant peak, suppress multiple tonal peaks, modify the behavior of the broadband component and reduce or amplify the overall slat noise.