Modelagem matemática e computacional de interações fluido-sólido utilizando o método de fronteira imersa tipo ghost em ambiente paralelo e com malha adaptativa

Abstract

Bodies subjected to external and internal flows can vibrate due to fluctuations in forces induced by the flows. These vibrations can induce, through a non-linear process, an increase in drag and lift forces, leading to loads increase acting on the structures. In addition, vibrations can cause nucleation and crack propagation in the structure, leading to fatigue failure. The objective of this work is the implementation of an immersed boundary method that allows the simulation of external and internal flows in a given structure, that isn't possible with classic methods. The equations with which the flows are modeled are solved in a Eulerian domain, while the surface of the submerged body is represented by a set of Lagrangian points. The computational code MFSim, fully developed in-house, was used, which allows the simulation of compressible and incompressible three-dimensional flows in parallel and with an adaptive mesh refinement. In the present work, the "ghost fluid" method (BERTHELSEN; FALTINSEN, 2008), was implemented and validated in the MFSim platform. The validations were developed by modeling and simulating flows over spheres and cubes, including the magnus effect. With the obtained results, it is shown that the implemented method is superior to the immersed boundary MDF (Multi Direct Forcing), already implemented in the same platform. The computational cost of both methods is similar. The Ghost method is suitable for modeling and simulating flows on both sides of a given geometry, which opens up possibilities for highly complex applications such as flows inside and outside a pipeline. In summary, the implemented method represents an important advance in the developments involving the MFSim platform, opening a wide range of future activities.