Gust Response Predictions of a Very Flexible Wing Model

Abstract

Nonlinear aeroelastic simulations are benchmarked against wind tunnel experiments of a very flexible wing. In the simulations, sectional force corrections are employed to capture low-Reynolds-number effects and the static lift deficiency due to the onset of flow separation. With these corrections, both the static and dynamic wing deformation predictions match the experiments well (2% and 6% error, respectively). Furthermore, a simulation of the unsteady inflow to the Delft-Pazy wing that is produced by the gust vanes in the wind tunnel is explored as an alternative to a frozen gust model. Results indicate a considerable influence of the wing’s presence on the gust velocity that was measured upstream of the wing in the wind tunnel experiment. The structural response, however, differs only slightly when using the two different gust models. This confirms that the uniform gust is still a valid assumption for moderately large deflections (up to 24% of the wingspan in this work). Finally, geometrically nonlinear effects are assessed and found to be relevant in the simulations because of the nonlinear aeroelastic equilibrium, but not because of the gust excitation.