Browsing by Issue Date, starting with "2021-04-13"
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- Numerical Study: The Influence of Front Wing Pressure Distribution on Wheel Wake AerodynamicsPublication . Martins, Daniel Filipe Teixeira; Correia, João Patrício Soares; Silva, André Resende Rodrigues daThe present study focuses on investigating the aerodynamical interaction between a threeelement wing and wheel in ground effect, regarding the Formula One regulations change set for 2022 - amongst the changes is the declutter of the front wing, consequently reducing its complexity. This was accomplished by conducting a three-dimensional computational analysis, using a Detached Eddy Simulation approach, on a simplified one-quarter CAD model, built from the ground up following the regulations imposed by the FIA. The main goal was to examine how changing the front wing pressure distribution affected wheel aerodynamics, which will then influence the feeding process of the underbody, due to their proximity and subsequent flow interaction. This was done by varying the angle of attack of the second flap on the wing. The CFD study was divided into two sections: a flow analysis and a force analysis. On the flow analysis, one focused on determining the location and intensity of flow energy losses; visualizing the flow structures around the wing and wheel; and, where possible, identifying and comprehending the mechanisms behind the observed flow phenomena. On the force analysis, the transient variations of the force coefficients were examined to better understand how the unsteadiness of the vortices influenced the wing’s performance. The flow investigation indicated that the wheel wake structure is significantly influenced by the wing’s flap configuration, showing different shapes to the different geometries tested. This is mainly due to the fact that different flap configurations produce different upwash flow fields, leading to a separation point variation on top of the wheel. This variation then affects the downwash observed behind the central region of the wheel, for a vertical plane. The force investigation showed that the location of the region of instability influences the behaviour of the transient oscillations, regarding the forces acting on the wing: bearing in mind that vortex breakdown occurs near the wing’s trailing edge, higher drag force fluctuations are detected, when compared to downforce fluctuations – a shared pattern across the geometries tested.
- Feasibility study to convert the operational risk management process of reports into Bowtie methodology at euroAtlantic AirwaysPublication . Martins, Jorge Miguel Silva Marques Gonçalves; Saúde, José Manuel Mota Lourenço da; Santos, Jorge Esteves Pereira Nunes dos; Menezes, Lídia Assunção Tavares BrandãoOver the years, the aviation community has focused its efforts on minimizing the risk aircraft face, such as human errors or technical issues. Whether with safety improvements, technological developments or stricter regulations, that path has always been the way towards the future. Therefore, airline operators must be aware of everything surrounding its operations, particularly the hazards that may compromise the normal safety levels. Following this, euroAtlantic airways felt the need to review its reports related to the Safety Risk Management process and to verify if it was still optimized or if it could be replaced by another method available in the market that could better serve the needs of the company. To do so, a feasibility study to convert the operational risk management process of reports into Bowtie methodology was implemented. It was carried out a bibliographic research on safety management system, hazard identification and risk assessment to better understand the processes previously implemented in the company. A Bowtie diagram for hard landing was created. Then, a real event of a hard landing reported in the company’s IQSMS, considered to be a crucial incident for the company’s operation, was analysed using EAA’s current method and the Bowtie methodology. The results of both analyses were then compared and revealed that even though the Bowtie methodology is a well-structured and recognized method within the industry, it is too complex for the reality of the company and its operation. It was concluded that the current method used, with specific upgrades in terms of the database, can continue to play its role. In the end, improvements were proposed to the system currently established, including updates in the database for the event’s categorization, as well as the introduction of the Bowtie methodology for analysing critical events like, for example, the hard landing.
- Caracterização da Margem do Disco Ótico numa População NormalPublication . Agrela, Cláudia Sofia Saldanha; Soares, Ivo Miguel da Fonseca Gravito; Almeida, Vasco Miguel Nina deA margem do disco ótico clinicamente visível é um dos principais marcos anatómicos a observar quando se faz uma avaliação da cabeça do nervo ótico. Estudos recentes mostram que a margem do disco ótico clinicamente visível em fundoscopias depende da conjugação de três estruturas anatómicas, nomeadamente a abertura de membrana de Bruch, o tecido de bordo de Elschnig e a esclera anterior. A conjugação destas três estruturas anatómicas resulta em três configurações anatómicas específicas, caracterizadas pela obliquidade do tecido de bordo. As três configurações anatómicas são a oblíqua interna, oblíqua externa e não-oblíqua. Ao longo da margem do disco ótico pode encontrar-se mais do que uma configuração anatómica, sendo que essa configuração pode modificar-se ao longo da vida humana. Sabe-se, também, que em certas condições patológicas, como o glaucoma ou miopia patológica, as configurações anatómicas observadas nestes sujeitos diferem bastante das observadas em sujeitos normais. Se estas alterações da configuração anatómica puderem ser detetadas de forma prematura poderá significar uma melhor deteção destas patologias. Na literatura não existem estudos sobre a configuração anatómica em sujeitos jovens saudáveis. Desta forma, neste trabalho avaliou-se quais as configurações anatómicas mais comuns numa população jovem saudável. Em particular, foram também avaliadas as diferenças entre sexo e ametropias pequenas.