Investigations of Transonic Aircraft in the Joint DLR / ONERA Project “Non-Linear Aeroelastic Simulation, NLAS II”

Abstract

The DLR Institute of Aeroelasticity and the ONERA Aeroelasticity and Structural Dynamics Department have a long, proven expertise in the development and the validation of aeroelastic tools for aircraft, and a long-standing cooperation both in experimental and numerical activi-ties. The common project NLAS II (2009-2012) was devoted to the assessment and the vali-dation of numerical aeroelastic technologies developed and used at the respective institutes of DLR and ONERA to simulate and predict the aeroelastic stability and response of aircraft in transonic flow. For that purpose, both partners could take advantage of high quality wind tunnel data availa-ble at the partners for the validation of the numerical approaches. Four common test cases covering a range of challenging and relevant physical phenomena have been selected. The phenomena include static coupling for the prediction of steady state flow and steady state wing deformation, as well as dynamic coupling for transonic flutter and Limit Cycle Oscilla-tions (LCO). Analyses both in the time domain and in the frequency domain have been undertaken, per-forming a wide range of Euler, RANS and URANS calculations. DLR used an aeroelastic process chain based on the TAU code, ONERA used the aeroelastic extension elsA/Ael of the elsA software. Static coupling results, unsteady forced motion computations for 2D and 3D flap motions, and dynamic coupling simulations for the prediction of Limit Cycle Oscillations are presented.