MODELAGEM COMPUTACIONAL DO FENÔMENO DE LOCK-IN EM UM CILINDRO EM VIBRAÇÃO LIVRE
DOI:
https://doi.org/10.26512/ripe.v2i25.20848Keywords:
Interação Fluido-Estrutura. Lock-in. Dinâmica dos Fluidos Computacional.Abstract
O objetivo do presente estudo ´e observar o fenômeno aeroelástico de ‘lock-in’ relacionado ao desprendimento cadenciado de vortices em um cilindro circular submetido a um escoamento de um fluido. A primeira an´alise feita apresenta o cilindro fixo, com condicao de contorno ‘no-slip’, a fim de se extrair o n´umero de Strouhal do sistema e os coeficientes aerodinamicos para Re entre 60 e 120. As an´alises subsequentes s˜ao Interacoes Fluido-Estrutura, onde o cilindro agora apresenta um grau de liberdade nao-restrito no sentido transversal ao fluido. As simulacoes sao feitas para varias velocidades de incidˆencia do fluido, na faixa correspondente a ressonancia com o desprendimento dos vortices. O escoamento apresenta Re entre 50 e 120, de forma que a frequencia natural do cilindro fosse proxima `a frequencia de desprendimento de vortices para Re = 100. As equacoes governantes para o fluido sao as de Navier-Stokes para escoamentos incompressveis e o cilindro tem comportamento el´astico com baixo amortecimento estrutural. Utilizou-se o software comercial ABAQUS e seus pacotes CFD (Computational Fluid Dynamics) e Standard. Os resultados s˜ao comparados com os correspondentes valores obtidos em demais trabalhos, realizados em simulacoes computacionais ou em ensaios em t´uneis de vento.
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