Konzeptstudie zu Stoßkontrollsystemen

Abstract

To save fuel and to improve the associated reduction of greenhouse gas emissions in aviation the laminar wing technology offers a promising potential. This includes technologies such as NLF (Natural Laminar Flow) and HLFC (Hybrid Laminar Flow Control). At transonic flights a supersonic region can occur in the flow field on the wing which leads to the development of a transonic shock. This shock increases the wave drag and consequently the total drag of the wing and thus of the whole aircraft. This leads to higher fuel consumption and accordingly to higher emissions. Shock Control Bumps (SCBs) are bumps or contour changes on the wing surface which offer a promising solution to reduce the strength of the transonic shock and thus wave drag. This phenomenon has been investigated intensively from an aerodynamic perspective which allows conclusions to be drawn regarding the shape and position on the wing of these bumps. Furthermore, these aerodynamic investigations show that the largest potential lies in adaptive SCBs which can be adjusted and modified according to changing flight and flow conditions. In this regard, the two most important control parameters are the height and position of the bump. Apart from aerodynamic effects of shock control systems, concepts for the technical feasibility of adaptive SCBs have been published. In this work, several concepts for enabling SCBs or reducing the shock strength are summarized and compared against each other. Aspects such as technical feasibility, structural and systems designs are considered in light of their benefits that they afford. Among them are on the one hand concepts which use primarily the spoiler actuator to from a bump and on the other hand concepts with several smaller actuators like the Tube Spring or the Fish-Mouth actuator as well as pressurized chambers. However, in this work special attention is paid to concepts of morphing contour bumps on the spoiler, e.g. reshaping of the original geometry, in contrast to other concepts like porous materials or plasma heating elements. Furthermore, a new concept of an adaptive SCB will potentially also be presented, pending on the availability of results.