Efficient and accurate simulation of the flow past moving bodies

Numerical methods in fluid dynamics have been developed for many years, now, with two main categories of method: Eulerian and Lagrangian methods, which both have their respective pros and cons. In order to achieve both the accuracy and computational efficiency of the numerical simulation of external flows, a new hybrid method has been developed by Billuart et al.. The latter enables to have a very fine resolution of the flow in the near-wall region and to capture the small scale details of the near wake, while convecting the wake over long distances, for the 2D simulation of incompressible external flows. This method relies on the weak coupling between a body-fitted, finite difference solver for the Navier-Stokes equations in the velocity-pressure formulation, and the Vortex Particle-Mesh method. The present work therefore consists in an adaptation of the methodology developed by Billuart et al. to moving rigid bodies. The method is verified for forced oscillations of a cylinder in the transverse direction to the free stream, and for a rotating cylinder in a free stream, experiencing the Magnus effect. The oscillation of a cylinder in the streamwise direction and the simulation of a heaving airfoil are presented as applications. Other applications to this work concern Fluid Structure Interaction (FSI), with a possible further step for adapting the method to soft bodies. A brief introduction to the different methods used throughout this thesis is provided in Chapter 1, as well as a short review of the literature in the domain of forced moving cylinders and Fluid Structure Interaction. Then, the detailed methodology of each component solver as well as the coupling strategy between both solvers for moving bodies is presented in Chapter 2, for moving bodies. Afterwards, the first results of the present method are presented in Chapter 3 in order to verify as far as possible the present method. Three cases of transverse oscillations of a cylinder in a free stream at Reynolds Re = 100, and a cylinder rotating at three angular velocities in a free stream at Re = 200 are presented. After that, three applications are presented. In Chapter 4, an oscillating cylinder in the streamwise direction, and a heaving airfoil in the free stream at Reynolds Re = 500 are presented. Finally, the achievements of this work are summarized and the further possible developments are discussed in Chapter 5.