Aeroelastic wind tunnel model for tail buffeting analysis using rapid prototyping technologies

Modern high-agility aircraft are often subjected to tail buffeting at moderate subsonic Mach numbers and medium to high angles of attack. The excitation of the tail structures through the unsteady flow field can lead to significant structural fatigue and degraded handling qualities. Various methods have been developed for the computational prediction of the phenomenon. The most common approaches use a partitioned coupling of Computational Fluid Dynamics (CFD) and Computational Structural Mechanics (CSM) solvers. Despite advances in computational prediction of buffeting wind tunnel models are still essential for buffeting analyses and validation of prediction methods. Flexible wind tunnel models are commonly designed using simple spar structures with covers for the aerodynamic shape or recently with more complex composite structures. In this paper we present the design and development of a flexible wind tunnel model for buffeting analysis using rapid prototyping technologies. 3D-printed flexible model components from polylactide provide enough flexibility to analyze buffeting effects in wind tunnel tests. At the same time, they show sufficient structural strength to withstand buffeting loads. Complex structural layouts and details can easily be manufactured to tailor the structural behavior. Here, we provide a first basis for the application of 3D printed parts for flexible buffeting wind tunnel models. The development of the model with high-fidelity methods of CFD and CSM is presented. Characteristics of the predicted flow field, finite-element modeling of the structural behavior and predicted buffeting loads are discussed. High structural stresses at the attachment points of the flexible model components could be lowered with slight structural modifications. Furthermore, we provide details on the successful manufacturing and instrumentation of the model.