Modelagem matemática de interação fluido-estrutura utilizando o método da fronteira imersa

Abstract

The practical engineering problems of incompressible flows over bluff bodies are considered as the most studied. The bluff bodies are affected by the hydrodynamic loads associated to the vortex shedding that in the most cases induce oscillated motions. The induced vibration motion due to the vortex shedding has been intensively investigated by a number of academic and industrial researches around the world. In this context, this work is devoted to the use of the so-called Immersed Boundary Method combined with the Virtual Physical Model for the purposes of numerical simulations of incompressible two-dimensional flows over circular cylinders. The numerical simulations emphasis is placed on the flows over rotating and rotating-oscillating cylinders, over two cylinders at different arrangements, and cylinders supported by elastic springs constituting one and two degrees-of-freedom systems. The Smagorinsky sub-grid turbulence model and a damping function in the outlet of the domain were used with to guarantee the numerical stability. The analyses of pressure distributions over the cylinder surface, time histories of drag and lift coefficients, Strouhal number as well as wake topology behind the cylinder were also presented. In the case of fluid-structure interaction, the responses of the cylinder were analyzed as functions of the reduced velocity, as well as the time histories of the cylinder displacement in the longitudinal and transversal directions. It was verified that the rotating motion can attenuate and in some cases eliminate the vortex shedding process, depending on the specific rotation. In the rotating-oscillations results, the vortex mode 2S , 2P and P+S , respectively, were obtained, and also elliptic wakes. Through the numerical results obtained one can verify that those are in accordance with those associated with the two-dimensional simulations. Finally, the numerical results presented in this work are in good agreement with the experimental and numerical corresponding results encountered in the literature.