Aircraft Wing Optimization Using High Fidelity Closely Coupled CFD and CSM Methods

Kurzfassung

The present paper describes a comprehensive MDO process chain to maximize the range of a transonic transport aircraft configuration. The parameterization incorporates wing plan form parameters and twist angles in four wing sections. The geometrical inputs for the disciplines CFD and CSM were generated by CATIA V5 based on those design parameters which were prescribed by a SUBPLEX optimizer. CFD is at first used to calculate the drag in cruise flight with RANS and secondly to provide aerodynamic forces from Euler solutions from certain maneuver cases for a structural sizing of the wing to yield the wing weight. As with the structural calculations the wing deformations are available, these are used to deform the CFD mesh and to evaluate drag and forces on the corresponding flight shapes. The fluid/structural-sizing procedure, which is performed in every optimization cycle, is repeated several times until a sufficient convergence of drag and wing mass is achieved. Both values are then used to compute the Breguet range, which represents the optimization objective. Finally two optimization runs have been conducted. While the first run lead to a consistent result, in the second run, which includes an additional load case, the best configuration was already found in the fifth cycle.