Discrete models for the analysis of 2D wakes in unsteady aerodynamics

A comparative numerical study of two-dimensional wake dynamics is presented. An application to the free wake motion behind an elliptical loaded wing on the Treffts plane is approximated either by the dynamics of a set of vortices (vortex method) or by the dynamics of a piecewise linear curve (boundary element method). In both approaches some considerations about the time integration accuracy control are made in terms of the most sensitive flow first integral: the Hamiltonian. Two types of the vorticity generation mechanism are tested in the second part of the paper where the application to the flow around a lentil at large incidence in an uniform stream is analysed. Some aspects of the coupling between the vorticity production and the wake interaction are discussed in order to explain the periodic vortex shedding.