A three-dimensional parallel adaptive mesh refinement method for fluid structure interaction.

摘要

Many physical phenomena of interest in fluid dynamics must contend with the presence of a moving boundary. Since the interaction of fluid flows with moving boundaries leads to a highly coupled, nonlinear system, such problems have remained essentially analytically intractable. The main difficulty is that the moving boundary itself must be determined as part of the solution of the system of equations which govern the behavior of the fluid flow field.;The purpose of this work is to introduce a general method for treating flows past arbitrary bodies undergoing large deformations. This is a further step in the development of numerical techniques for the analysis of fluid problems with moving boundaries.;The method is implemented using a block-structured adaptive mesh refinement approach. This allows the code to automatically tackle the need to track and capture large displacements and deformations, and the consequent unsteady flow features with no alteration of the code or user input. The code is developed in a parallel implementation, therefore addressing the need of quick simulation time and handling very large problems. The tool developed has the ability of tracking several different bodies at the same time. They may be rigid or undergoing prescribed or actual deformation. Moreover there is the capability of specifying actuator forces rather than displacements. This is a unique feature that, coupled with the eventual presence of a controller logic in the code, will advance the state of the art of current simulation tools.;The model developed underwent several tests to investigate its limits. The model proved to be able to perform as planned. The simulation of the flow around sphere in different regimes, proved the calculation of forces, an essential feature in a fluid-structure coupled problem, to be accurate in both steady and unsteady regimes.;Moreover, both the tracking of the surface and of the flow features were handled seamlessly, as shown by the different flapping motion simulated. Initially the wing is maintained rigid and displacements are prescribed. Then the rigidity constraint is removed and the flapping motion of both actively and passively deforming wings is simulated.