AbstractsBiology & Animal Science

In the field of computational aerodynamics, the vortex particle-mesh (VPM) method provides an interesting alternative to standard CFD methods currently available on the market of simulation tools. The associated numerical properties, enabled by its Lagrangian nature, make it highly competitive for the simulation of free vortical flows, such as aircraft wakes and jets. Yet, accounting for solid bodies (e.g. planes, wind turbines, etc.) remains challenging, despite the extensive research efforts that have been made for several decades. Based on an immersed interface method, the approach developed in the present thesis aims at improving the consistency and the accuracy of one very common technique (based on Lighthill's model) for the enforcement of the no-slip condition at the wall in vortex methods. Targeting a sharp treatment of the wall calls for substantial modifications at all computational levels of the VPM solver. More specifically, the solution of the underlying Poisson equation, the computation of the diffusion term and the particle-mesh interpolation have been adapted accordingly and the associated spatial accuracy has been assessed. The resulting immersed interface-enabled VPM solver has been subsequently validated on the simulation of some challenging impulsively started flows past profiled and bluff bodies. Results show that the present method is able to compete with purely Lagrangian methods in terms of the force prediction, which is quite remarkable. In addition, two other aspects of VPM methods have been studied, namely the temporal accuracy of the no-slip enforcement and the quantification of the numerical dissipation and dispersion errors due to the particle redistribution. (FSA - Sciences de l)  – UCL, 2014