Simulation of longitudinal vortices in high-lift of transport aircraft-

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Modern transport aircraft often use vortex generators located at the engine nacelle in order to suppress local boundary layer separations on the main wing. A reliable prediction of these longitudinal vortices and their effects on the wing is not possible today due to the lack of a validated simulation strategy that would allow applications at the typical Reynolds numbers of aircraft flight. The project objective is the establishment of a well-founded methodology for numerical flow prediction of wings in the high-lift configuration, where the boundary layer interacts with a longitudinal vortex. The simulation methodology will be validated with a wind tunnel experiment. The experimental and numerical data base will be analysed for new knowledge about role that the different flow scales of the vortex and the adverse-pressure-gradient boundary layer assume in the overall interaction phenomenon. The analysis will particularly quantify the effects of unsteady vortex wandering, which has been previously observed in wind tunnel experiments and during flight. The aspired methodology consists of an adaptive, hybrid RANS-LES model that uses a Reynolds stress model of turbulence for the RANS region and a wall-modelled LES for the region with scale resolved turbulence. The model will be used to answer the question, whether the interaction of a free longitudinal vortex and the boundary layer with an adverse pressure gradient must be simulated with a hybrid, scale resolving approach, or the major effects may be qualitatively and quantitatively represented by a suited Reynolds stress model.