Experimental Investigations of a Wind Tunnel Model for the Analysis of Fluid-Structure Interaction caused by the Influence of Leading-Edge Vortex Systems

Modern, high-agility aircraft develop separation-induced leading-edge vortices and vortex flow aerodynamics in various portions of their flight envelope. At higher angles of attack, vortex-bursting results in an unsteady flow field downstream of the breakdown region. High turbulence intensities and their distinct burst frequency content can lead to structural dynamic excitation of the wing and downstream located elements such as tail planes. This aerodynamic excitation may cause dynamic aeroelastic phenomena like wing and fin buffeting. A generic wind tunnel model has been developed at the Chair of Aerodynamics and Fluid Mechanics (TUM-AER) of the Technical University of Munich (TUM) for the experimental analysis of buffeting phenomena. The full-span configuration features a 76°/40° double-delta wing, a pivotable horizontal tail plane (HTP) and a vertical tail. The modular design of the wind tunnel model allows investigations on flexible lifting surfaces and quasi-rigid lifting surfaces. The measurement campaign takes place at the TUM-AER low-speed wind tunnel A (WT-A). An internal six-component strain gauge balance is used to measure aerodynamic forces and moments. In addition, the model is equipped with unsteady pressure transducers and accelerometers. Furthermore, the eigenmodes of the flexible and quasi-rigid configuration are determined by a ground vibration test (GVT). Analyzing the spectral content of the pressure fluctuations it is shown that the breakdown flow exhibits a significant buffet peak. With an increasing angle of attack, a shift of the dominant frequencies of the buffet peaks to lower frequencies can be observed. Considering the aerodynamic excitation, no significant differences between the flexible configuration and the rigid reference case can be observed. However, in the analysis of the structural response, clear differences could be determined.     «

Modern, high-agility aircraft develop separation-induced leading-edge vortices and vortex flow aerodynamics in various portions of their flight envelope. At higher angles of attack, vortex-bursting results in an unsteady flow field downstream of the breakdown region. High turbulence intensities and their distinct burst frequency content can lead to structural dynamic excitation of the wing and downstream located elements such as tail planes. This aerodynamic excitation may cause dynamic aeroelas...     »