Analysis of forced response in a wind tunnel based on Doublet-Lattice method

Abstract

A wind tunnel experiment for the validation of gust response computations has been performed. The model consists of an active two-dimensional rigid front wing acting as a gust generator and forcing an elastic backswept rear wing. Results of numerical simulations with gust generation are presented. For the setup of the experiment, a simulation environment was established to identify the effect of different installation positions by parameter variation and to point out the efficiency of gust generation in the wind tunnel. The aerodynamic forces are computed by a subsonic Doublet-Lattice method (DLM) which provides considerable computational efficiency and flexibility of the numerical approach. DLM is used as a standard unsteady aerodynamic tool for gust problems and enables comparisons with CFD results. A large number of numerical results in frequency and time domain are used to obtain the forced motion of the elastic back-swept wing located downstream of the gust generator and to simulate the aerodynamic interaction in the wind tunnel. This enables a survey of gust loads on the back-swept wing in comparison to gust and turbulence loads calculated according to airworthiness standards. Furthermore, the numerical results are compared to the experimental results measured in the Transonic Wind tunnel Göttingen of the German-Dutch Wind Tunnels.

Design and aeroelastic assessment of a forward-swept wing aircraft

“…One main aspect was the influence of laminar wing design on divergence, flutter and dynamic loads. The work packages of the project were dedicated to the following topics: the investigation of the influence of the dynamic motion of the laminar/turbulent transition point on the flutter boundary [1,2]; an extensive numerical and experimental campaign including a newly designed gust generator facility in the transonic wind tunnel Göttingen [3,4], and studies on the influence of thrust vector motion and gyroscopic effects on flutter. Finally, relevant conclusions from all work packages were to be demonstrated on a numerical application, the design and analysis of a reference aircraft configuration.…”