Assessment of Active Load Control Approaches for Transport Aircraft - Simulation and Wind Tunnel Test

Kurzfassung

Active flight load alleviation is an important contribution towards lighter wing structures and wings of higher aspect ratios, both important measures to increase the efficiency of transport aircraft. In the DLR project oLAF (optimal load adaptive aircraft), strategies for active and passive load alleviation are developed and validated. In the project, different lines of investigation are followed in parallel - first, a reference configuration of a long range aircraft is designed on a preliminary design basis, and both aerodynamics and structure of the wing are further optimized using coupled CFD- and finite-element-based design methods. Second, various aspects of load control technologies are studied independently, and the results are applied using the design process of the reference aircraft. Third, a closer look it taken at the aerodynamics of spoilers and control surfaces. Finally, high-fidelity methods are employed for a further development of MDO aircraft design processes. Outputs of the aforementioned activities form the basis for the definition of a wind tunnel experiment for the validation of active load alleviation approaches in the DNW-NWB low speed wind tunnel. The planform of the wind tunnel wing is derived from the overall aircraft design. Aeroelastic tailoring approaches are used for the design of the wing structure. The active control laws applied in the experiment are derived from the control design approaches developed for the complete aircraft. For the flow excitation, a new gust generator has been developed. The results of the wind tunnel experiment are used for the validation of the numerical approaches developed in the project. This paper focusses on the specifications of the wind tunnel experiment resulting from the overall project investigations and the contributions of the experiment to the project goals. Further papers will provide detailed descriptions of the wing design and the wind tunnel experiment.