Concept of a morphing shock control bump spoiler with two actuators

Abstract

The overall goal of reducing greenhouse gas emissions in commercial aviation can be approached in many ways. One of them is the reduction in fuel consumption by reducing aerodynamic drag. Morphing can be used to adapt the shape of surfaces to gain aerodynamic benefits such as drag reduction under specific flight conditions. Among other things, drag reduction can be achieved by transonic shock control. In this work, the concept of a morphing spoiler which can form a shock control bump is investigated. This bump is shape adaptive and can shift its crest to different locations on the spoiler as well as retract the bump entirely. While the upstream bump crest position is optimized for drag reduction, and thus performance increase, the downstream position is optimized for delaying the buffet onset. This positionvariable functionality is realized by using a second actuator in addition to the main spoiler actuator. A structural finite element optimization considering aerodynamic loads in form of pressure distributions is performed. The load cases cruise, with and without deployed bumps as well as the airbrake configuration are investigated. The structural concept of the spoiler is described as well as its optimization process that is based on the Nelder-Mead method. For this purpose, the finite element software ANSYS is coupled to MATLAB in which the optimization is controlled. In the end, it is shown that a morphing spoiler with two actuators can form a position variable shock control bump under realistic aerodynamic loads.