An Adjoint-based Optimization Method for Helicopter Fuselage Backdoor Geometry

For utility and transport helicopters with rear loading backdoors, the afterbody area is usually one of the largest drag contributing areas of the fuselage. For this reason, numerical simulations have been performed to assess the possibilities of fuselage drag reduction by the means of local shape modification at the afterbody region. Within this study an automatic optimization chain with gradient-based optimization technique and surface parameterization/deformation tools has been established and applied to the backdoor geometry of a modified GOAHEAD configuration. This paper will present the first numerical results of the ongoing shape optimization studies. As it turns out, local shape modification on the backdoor geometry can lead to a reduction of the separation region there and to a drag reduction of the helicopter fuselage