Chimera Simulations of Transported Large–Scale Vortices and Their Interaction with Airfoils

A Chimera technique for moving grids is applied to simulate the transport of large-scale vortices convected by a mean velocity field over large distances and their interaction with an airfoil. While keeping the numerical dissipation at a minimum, the Chimera approach allows to resolve the vortex on a local fine grid whereas the unstructured global background grid can be relatively coarse. Having examined the vortex dissipation rate numerically, the interaction of a Rankine-like type vortex with a NACA 0012 airfoil and an ONERA-A airfoil near stall, respectively, is simulated. The interaction can be interpreted as a time-dependent variation in the effective angle of attack. A subsequent computation of a flapping NACA 0012 airfoil turns out to be an insufficient approximation of the vortex-airfoil interaction.