The strategic goal of the MORALI project was to improve the rotor design capability, including comprehensive analysis and evaluation skills of different designs, simulation competence at various modelling levels, and automated optimisation support. While helicopter rotor design involves many different disciplines, with often conflicting demands. However, this proposal only addressed the aerodynamic problems, taking other requirements into account by properly defined constraints.

Aerodynamics of helicopters is a very demanding undertaking in itself, challenging the underlying modelling as well as high performance computing capabilities. The toolbox in this project consisted of blade element models at the lower end of the methodology spectrum as well as coupled flow-structure dynamics simulations at the high fidelity side.

The blade element model was improved by a semi-empirical modelling of dynamic stall, very important for aerodynamic performance, but also for endurance estimations. Furthermore, the wake modelling was enhanced to represent flow phenomena generated by local wake structures better at this modelling level.

CFD can benefit from the introduction of a transition model to take laminar flow at the leading edge into account. Additionally, the trim procedure was sharpened, taking advantage of automatic trim time decision and convergence acceleration.

Both are used to optimise sensibly chosen free parameters in the design process, taking advantage of a comprehensive assessment of the detailed rotor simulation results. This assessment included acoustic post-processing of the simulations and emulates the qualified analysis of an experienced engineer, in order to attenuate artificial deficiencies in the numerical procedures involved.

Finally, the developed tool chain was used for the optimisation of a specific rotor design and the results validated using trusted high-fidelity CFD simulations.