Numerical optimization of helicopter rotor aerodynamic performance in hover

An optimization procedure for helicopter rotor aerodynamic performance is presented. This optimization procedure is centered on the numerical optimizer CONMIN, a gradient-based method that minimizes a functional under constraints. The optimizer has been coupled to a 31) Navier-Stokes CFD solver elsA, and applied to helicopter rotor optimization in hover. The optimization chain and its components are first described. Several validations and applications are then presented starting from the 7A and 7AD rotor geometries with optimization of the different blade shape parameters (twist, chord, sweep and anhedral distribution). The efficiency and the robustness of the method are then tested for some more complex applications starting from the ERATO rotor. Finally a synthesis is made showing that the optimization chain is an helpful tool for the design of new helicopter rotors. (c) 2005 Elsevier SAS. All rights reserved.