Maximum growth of Gortler vortices

International audienceThis study is concerned with the numerical calculation of the maximum spatial growth of Gortler vortices on a concave wall. The method is based on the direct computation of a discrete approximation to the spatial propagator that relates the downstream response to the inlet perturbation. The optimization problem is then solved directly by making use of the propagator matrix. The inlet optimal perturbations and the outlet optimal response that are found are similar to those found with the same measure by Andersson et al. [1] and Luchini [5] in the case of the boundary layer on a flat plate. The study of a simple "toy" model problem suggests that the streamwise evolution of perturbations is essentially determined by the non-normality of the spatial propagator