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This document explains in its first part the design procedure adopted to design the contoured sidewalls of a swept-wing airfoil section mounted in a wind tunnel in order to satisfy the infinite swept-wing approximation. In the second part, the experimental set-up is described as well as the first results of the experimental campaign. The sidewalls are shown to play their role properly and satisfactorily provide the infinite swept-wing conditions required for subsequent investigations of the most important vortex receptivity mechanisms responsible for excitation of crossflow and Tollmien-Schlichting instability modes in the airfoil boundary layer.

This paper presents a numerical study of the acoustic shielding of aeroengine noise by the aircraft structure. More specifically, the engines considered are contra-rotating open rotors in pusher mode which are installed at the rear of the aircraft. Several empennage designs and engine positions are evaluated. An original method for the calculation of engine noise installation effects is presented and its application to contra-rotating open rotor propulsion is demonstrated. It is based on the weak coupling between computational fluid dynamics, an integral method based on Lighthill's analogy for the calculation of acoustic radiation, and on a boundary element method for the calculation of the acoustic diffraction by the aircraft fuselage and empennage. The prediction of a pylon-installed (isolated) contra-rotating open rotor noise directivity is presented and compared to equivalent wind-tunnel measurements. In both cases, the simulation and experiment are performed at 1:7 scale. In addition, the installation effect of the wind-tunnel, being nonanechoic, is also assessed with the numerical approach presented. Finally, for each aircraft configuration of interest, equipped with two rear contra-rotating open rotors, the predicted noise impact on the ground is evaluated. Of these, the contra-rotating open rotor mounted above an L-tail empennage is found to be the most beneficial configuration in terms of acoustic shielding.

The design of high-lift systems represents a challenging task within the aerospace community, being a multidisciplinary, multi-objective and multi-point problem. The DeSiReH (Design, Simulation and Flight Reynolds Number Testing for Advanced High-Lift Solution) project, funded by European Commission under the 7th Framework Program, aimed at improving the aerodynamics of high-lift systems by developing, in a coordinated approach, both efficient numerical design strategies and measurement techniques for cryogenic conditions. Within DeSiReH, different partners used several numerical automatic optimization strategies for high-lift system design purposes. A realistic multi-objective and multi-point optimization problem was defined and solved by adopting different flow models dimensionality, meshing techniques, geometry parameterization and optimization strategies. Special attention was devoted to perform a fair comparison of the results and useful information were obtained about trends, pros and cons of the approaches used. The outcome of these activities is that an efficient design

Tip-mounted propellers can increase wing aerodynamic efficiency, and the concept is gaining appeal in the context of hybrid electrical propulsion for greener aviation, as smaller and lighter electrical motors can help with mitigating structural drawbacks of a tip engine installation. A numerical study of tip propeller effects on wing aerodynamics is herein illustrated, considering different power configurations of a Regional Aircraft wing. A drag breakdown analysis using far-field methods is presented for one of the most promising configurations, and a comparison between drag reductions obtained with a tip propeller or a standard winglet installation is also provided. Numerical flow simulations using Finite Volume Methods with actuator disk models are compared with results of a Vortex-Lattice Method, and far-field aerodynamic force calculation is performed for different mesh sizes. A wing drag reduction up to 6% (10%) is predicted under typical cruise (climb) flight conditions when wingtip-mounted propellers take over half of the total thrust usually provided by turbo-prop engines installed at inboard wing position. Drag breakdown analysis confirmed that the observed benefits mainly come from a reduction in the reversible drag component, increasing the effective wing span efficiency.