Witness, Justice, and the Silent Confessional

Stories depicting injustice are inherently complicated by the limitations of language. Jacques Derrida’s “Circonfession” uses deconstructionist theory to describe the flawed nature of the confession in that proximity becomes problematic: those who experience are unable to authentically deliver the truth of that experience. Language also becomes an imperfect channel through which to deliver the truth; the truth lies in both a person’s ability to bring meaning to individual experience, but also, in an audience’s ability to interpret that experience; however, both sides of the conversation are challenged through an imperfect channel of communication. Therefore, silence of human behavior may very well be the ultimate exposure of injustice: what is unsaid becomes more telling, body language, unique word choice, and the ways people arrange their bodies. Mary Rowlandson’s Narrative and Edward P. Jones’ novel The Known World both explore experiences in which language becomes more of a fallacy, failing to directly expose an unjust world, despite the authors’ attempts in using language as a means to expose an unjust truth. Ultimately, language indirectly exposes injustice by being descriptive of a hierarchical system

Optimisation of Trailing Edge Flaps on the Base Cavity of a Vehicle for Improved Performance at Yaw

Regulations to reduce greenhouse gas emissions of passenger vehicles are becoming increasingly stringent. The aerodynamic drag is a major contributor to the vehicle\u27s total energy consumption where a large portion is attributed to the base wake. This paper optimises the angles of small trailing edge flaps on a base cavity of a full-scale sports utility vehicle placed in a wind tunnel. The trailing edge flaps are controlled using servos mounted inside the cavity. The flap angles are optimised using a surrogate model based optimisation algorithm with the objective of reducing the aerodynamic drag at different yaw angles and to create a yaw-insensitive geometry by considering several weighted yaw angles to form the driving cycle averaged drag. Low drag designs are further investigated using base pressures and wake measurements. The results show that the base pressures are symmetrised by reducing the crossflow in the wake. As the model is yawed the wake becomes increasingly downwash dominated by a large rotating windward structure which is reduced by the optimised flaps. The cycle averaged drag optimised design has a smaller increase in drag when yawed compared to a design optimised without considering yaw

Tyre Pattern Features and their Effects on Passenger Vehicle Drag

In light of the drive for energy efficiency and low CO 2 emissions, extensive research is performed to reduce vehicle aerodynamic drag. The wheels are relatively shielded from the main flow compared to the exterior of the passenger car, however, they are typically responsible for around 25% of the overall vehicle drag. This contribution is large as the wheels and tyres protrude into the flow and change the flow structure around the vehicle underbody. Given that the tyre is the first part of the wheel to get in contact with the oncoming flow, its shape and features have a significant impact on the flow pattern that develops. This study aims at identifying the general effects of two main tyre features, the longitudinal rain grooves and lateral pattern grooves, using both CFD and wind tunnel tests. This is performed by cutting generic representations of these details into identical slick tyres. Combinations of the two resulted in four physical tyre patterns that are tested on both a production and a closed rim. The test setup is reproduced in CFD taking the tyre deformation under loading into account. Due to the tyre\u27s deformation, Moving Reference Frame - grooves (MRFg) was used to model rotation, while the rim spokes were modelled with the sliding mesh approach. The results indicate that the rain grooves play a significant role in reducing drag when introduced on a slick tyre both in test and simulations, while the results from adding lateral grooves were less consistent dependent on the rim-tyre combination. The interaction between the longitudinal and lateral grooves could be observed on the overall vehicle drag. In general, CFD is able to predict the drag changes for different tyre patterns with good accuracy for the open rim, however the closed rim case proved to be more challenging

Validation of Different Fan Modelling Techniques in Computational Fluid Dynamics

The accuracy of predicting the engine bay flow field with computational fluid dynamics (CFD) is crucial for designing efficient cooling systems for heat sensitive components. The engine cooling fan is the main driving component in cases of high thermal load, such as uphill driving with a trailer, or high speed driving on a highway, when the ram air itself is no longer sufficient for cooling purposes.The most widely used fan modelling method is the Moving Reference Frame (MRF). This method can be used in steady and unsteady simulations, but has the drawback of using a fan geometry that is fixed in the global reference frame and, therefore, causing non-physical low velocity regions in the wake ofthe blades. The Rigid Body Motion (RBM or ”sliding mesh”) approach is a more accurate, but also more expensive approach, since it uses an unsteady solver. This study looks closely at the prediction of the flow field in the wake of an axial fan for different freestream velocities and fan speeds using the traditional MRF and RBM approach. In addition, a method that uses the average of flow field data for multiple MRF simulations with different fan positions is presented. Thereby the shadow of the fan blades is removed from the wake and the flow field becomes more uniform without the need of performing unsteady simulations. As a reference, measurements are performed on a vehicle fan with a 2D Laser Doppler Anemometry set-up in a small scale wind tunnel.The results show good agreement between the measurements and the RBM simulations. As expected, the MRF simulations show a distinct blade pattern in the wake flow field. This was successfully removed by the proposed averaged MRF method. Even though there are still some differences between this method and the experimental results, the average MRF method has shown to be applicable as it improves the flow field results at a relatively low computational cost

Evaluation of wind tunnel interference on numerical prediction of wheel aerodynamics

For a passenger vehicle, approximately 25% of the total\ua0aerodynamic drag\ua0originates from the wheels, making the aerodynamics of wheels a significant factor for the overall performance of a vehicle. To understand the complex flow field created by the rotational condition and geometry of these bluff-bodies, numerical simulations are often used. However, computations are frequently performed in domains that replicate open road conditions, differing from the conditions of\ua0wind tunnels. Therefore, to properly validate a\ua0CFD\ua0procedure and to correlate physical tests to numerical results, interference effects of the wind tunnel need to be investigated and their impact on the aerodynamics of wheels analysed and compared to that of open road calculations.In this study, numerical simulations on the DrivAer model were performed using different tyres and rims in both open road conditions and with the inclusion of a detailed model of a slotted walls wind tunnel. The results of the simulations are compared to experimental data, consisting of forces and flow field measurements. It was found that the inclusion of the wind tunnel in the computations improves the prediction of the flow fields, resulting in better prediction of both the absolute drag values and the drag deltas between configurations

Qual a melhor música para se ensinar? reflexões sobre arte e gosto musical a partir das observações no PIBID

Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014O presente trabalho, traz algumas reflexões que se originaram e se ampliaram ao longo das observações do Programa Institucional de Bolsa de Iniciação à Docência (PIBID). Levando em conta as colocações das Diretrizes Curriculares Estaduais do Paraná, acerca do ensino dos três tipos de arte existentes na sociedade, a arte erudita, a arte popular e a indústria cultural, procurou-se refletir sobre maneiras de integrar esses conhecimentos para proporcionar aos alunos das escolas observadas, um melhor desenvolvimento de seu senso crítico, de sua capacidade criadora e de sua consciência em relação à música em gera

Surrogate-based optimisation using adaptively scaled radial basis functions

Aerodynamic shape optimisation is widely used in several applications, such as road vehicles, aircraft and trains. This paper investigates the performance of two surrogate-based optimisation methods; a Proper Orthogonal Decomposition-based method and a force-based surrogate model. The generic passenger vehicle DrivAer is used as a test case where the predictive capability of the surrogate in terms of aerodynamic drag is presented. The Proper Orthogonal Decomposition-based method uses simulation results from topologically different meshes by interpolating all solutions to a common mesh for which the decomposition is calculated. Both the Proper Orthogonal Decomposition- and force-based approaches make use of Radial Basis Function interpolation. The Radial Basis Function hyperparameters are optimised using differential evolution. Additionally, the axis scaling is treated as a hyperparameter, which reduces the interpolation error by more than 50% for the investigated test case. It is shown that the force-based approach performs better than the Proper Orthogonal Decomposition method, especially at low sample counts, both with and without adaptive scaling. The sample points, from which the surrogate model is built, are determined using an optimised Latin Hypercube sampling plan. The Latin Hypercube sampling plan is extended to include both continuous and categorical values, which further improve the surrogate\u27s predictive capability when categorical design parameters, such as on/off parameters, are included in the design space. The performance of the force-based surrogate model is compared with four other gradient-free optimisation techniques: Random Sample, Differential Evolution, Nelder–Mead and Bayesian Optimisation. The surrogate model performed as good as, or better than these algorithms, for 17 out of the 18 investigated benchmark problems

PIBID música: articulações possíveis entre as práticas pedagógicas do projeto e a licenciatura

Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014Este trabalho teve como objetivo traçar um paralelo entre as experiências vividas no subprojeto de Música do PIBID da Universidade Estadual de Ponta Grossa com algumas das disciplinas estudadas no primeiro ano do curso. Foram abordados aspectos referentes às disciplinas de Didática e Prática Pedagógica I e como auxiliam na elaboração e realização de propostas no projeto. O subprojeto teve início em agosto de 2012 e atualmente conta com 12 acadêmicos, duas professoras supervisoras e um coordenador de área, sendo realizado em duas escolas. A partir das discussões é possível afirmar que o PIBID tem atuado como elemento mediador entre as disciplinas do curso, em especial as de cunho pedagógico, e as atividades, observações e discussões realizadas no projeto, atualizando conceitos estudados nas disciplinas e proporcionando um melhor entendendo de suas funções e objetivo

Flow angularity investigations in an automotive slotted wall wind tunnel

The Volvo Cars aerodynamic wind tunnel has had a vortical flow angularity pattern in the test section since its original commissioning in 1986. The vortical flow nature persisted after an upgrade in 2006, when the fan was replaced and a moving ground system was introduced. It has been hypothesized that the cause for this flow angularity pattern was leakages around the heat exchanger installed in the settling chamber. The present paper tests this hypothesis by measuring the flow angularity in the test section before and after sealing the leakages. The findings show that the leakage path around the heat exchanger does not influence the flow angularity, and that the current pattern is different compared to the commissioning after the upgrade. This prompted an investigation of the influence from the turbulence screens, which were changed after the upgrade commissioning. These investigations indicate that the probable cause of the vortical flow angularity pattern is residual swirl from the fan. Force measurements on a reference car with and without extra induced flow angularity show that the flow angles measured in the tunnel for regular operation are most likely small enough to not have a significant effect on the measured aerodynamic forces