Within task three "Numerical Simulations" in the project "HINVA-High Lift INflight Validation" extensive numerical verification studies based on a CAD model of DLR's A320-232 "Advanced Technology Research Aircraft" in landing configuration are carried out. Therein special attention is paid to the effect of certain geometric features of the high-lift system, such as slat tracks, de-icing pipe etc. Also the empennage and a model of both the operational engine and a through flow nacelle are included in the geometry. The numerical simulations are carried out using two different sets of flow solver settings. The first based on the Spallart-Allmaras turbulence model represents DLR's current best-practice. The second set follows a high-precision approach based on a differential Reynolds stress turbulence model. In this paper the structure of the task is presented along with results of initial numerical simulations assessing the influence of the slat tracks, the de-icing pipe and the TFN in comparison to the operational engine.

A numerical study was carried out to assess the interference effects between the wake of a transport aircraft and several generic cargo bodies during the early stage of an airdrop scenario. DLR carried out extensive wind tunnel airdrop investigations between 2006 and 2012. Based on the experimental data and preceding numerical simulations distinct positions of the trajectory being subject to strong interference effects were statically reproduced. The flow field around the bodies was experimentally investigated using stereoscopic Particle Image Velocimetry and compared to steady and unsteady Reynoldsaveraged Navier-Stokes (RANS) computations. The latter were carried out using the unstructured DLR TAU code. The primary focus is to assess the suitability, accuracy and the limitations of RANS methods in such challenging flow conditions. Therefore, the influence of several turbulence models was investigated and compared to experimental field velocity data. In addition, an exemplary unsteady RANS simulation was conducted to highlight the differences to the steady approach. Although deviations in the wake of the bodies were observed, the qualitative agreement between the steady simulations and experiment was very good. Quantitatively, however, the steady approach leaves room for further improvements. The gap to the experimental data could partially be reduced in applying unsteady RANS methods.

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