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Publication
Eficiência aerodinâmica e de refrigeração dos capacetes CatLike
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Abstract(s)
Atualmente, os capacetes de ciclismo são mais do que um simples adereços de segurança. Aspetos como a aerodinâmica e o conforto térmico têm sido incorporados no processo de design e desenvolvimento de um capacete pelos fabricantes. Adicionalmente, o ciclismo é um desporto em crescimento, impulsionado pelo desenvolvimento de ciclovias nas cidades a nível mundial e pela crescente consciência de um estilo de vida mais saudável. O presente estudo teve como principal objetivo avaliar a eficiência aerodinâmica do capacete de ciclismo A, da marca CatLike, através de ensaios experimentais em túnel de vento e de modelos numéricos desenvolvidos por CFD, no OpenFOAM. Os resultados obtidos a partir destes modelos foram posteriormente analisados e comparados com os resultados obtidos nos testes experimentais. Foram realizados dois ensaios experimentais: o primeiro consistiu na medição de velocidades em vários pontos da esteira do conjunto molde-capacete A, incluindo a visualização do escoamento através da injeção de fumo; o segundo teve como objetivo
avaliar e comparar a aerodinâmica do capacete A com a de um capacete de uma marca concorrente.
Relativamente aos modelos numéricos, estes tinham como objetivo reproduzir os ensaios experimentais. Além disso, este estudo tinha também como objetivo avaliar a eficiência de refrigeração do capacete, contudo não foi possível realizar ensaios em túnel de vento que permitissem concluir esta avaliação, assim como o desenvolvimento de um modelo numérico capaz de analisar a ventilação do capacete. Por fim, concluiu-se que os modelos desenvolvidos no OpenFOAM apresentaram pontos consistentes com os ensaios experimentais, apesar da discrepância de resultados e que o capacete A apresenta melhor desempenho aerodinâmico do que o
capacete da marca concorrente.
Currently, cycling helmets are more than just simple safety accessories. Aspects such as aerodynamics and thermal comfort have been incorporated into the design and development process of a helmet by manufacturers. Additionally, cycling is a growing activity, driven by the increase of the construction of bike lanes and by the raise of awareness of a healthier lifestyle. The present study aimed primarily to evaluate the aerodynamic efficiency of the A cycling helmet, by the brand CatLike, through experimental wind tunnel tests and numerical models developed using CFD in OpenFOAM. The results obtained from these models were subsequently analyzed and compared with the results from the experimental tests. Two experimental tests were conducted: the first consisted of measuring velocities at various points along the wake of the mould-helmet A assembly, including flow visualization through smoke injection; the second aimed to evaluate and compare the aerodynamics of the A helmet with a helmet from a competing brand. Regarding the numerical models, these aimed to recreate the experimental tests. Furthermore, this study also intended to evaluate the cooling efficiency of the helmet; however, it was not possible to carry out wind tunnel tests that would allow this evaluation, nor develop a numerical model capable of analyzing the helmet’s ventilation. Finally, it was concluded that the models developed in OpenFOAM exhibited points consistent with the experimental tests, despite discrepancies in the results, and that the A helmet demonstrates better aerodynamic performance than the competing brand helmet.
Currently, cycling helmets are more than just simple safety accessories. Aspects such as aerodynamics and thermal comfort have been incorporated into the design and development process of a helmet by manufacturers. Additionally, cycling is a growing activity, driven by the increase of the construction of bike lanes and by the raise of awareness of a healthier lifestyle. The present study aimed primarily to evaluate the aerodynamic efficiency of the A cycling helmet, by the brand CatLike, through experimental wind tunnel tests and numerical models developed using CFD in OpenFOAM. The results obtained from these models were subsequently analyzed and compared with the results from the experimental tests. Two experimental tests were conducted: the first consisted of measuring velocities at various points along the wake of the mould-helmet A assembly, including flow visualization through smoke injection; the second aimed to evaluate and compare the aerodynamics of the A helmet with a helmet from a competing brand. Regarding the numerical models, these aimed to recreate the experimental tests. Furthermore, this study also intended to evaluate the cooling efficiency of the helmet; however, it was not possible to carry out wind tunnel tests that would allow this evaluation, nor develop a numerical model capable of analyzing the helmet’s ventilation. Finally, it was concluded that the models developed in OpenFOAM exhibited points consistent with the experimental tests, despite discrepancies in the results, and that the A helmet demonstrates better aerodynamic performance than the competing brand helmet.
Description
Keywords
Aerodynamics Cycling helmets Computational Fluid Dynamics (CFD) Numerical validation OpenFOAM Wind tunnel Aerodinâmica Dinâmica de Fluídos Computacional Capacetes de ciclismo Túnel de vento Validação numérica