Aeroelasticity of a laminar wing

Abstract

Within the DLR Institute of Aeroelasticity project iGREEN (integrated green aircraft) the aeroelastic behavior of a typical laminar airfoil under unsteady transonic flow conditions was to be investigated. For that a 2D airfoil model was build and tested in the transonic wind tunnel facility DNW-TWG in Goettingen. The model is a 2D-section with a CAST-10 profile, made of carbon reinforced fiber (CRF). It is equipped with 60 unsteady pressure sensors placed in one section and with hot-film sensors located on its upper and lower surface between 10% and 85% in steps of 5% in streamwise direction, 16 on each side. In order to get a smooth surface without disturbing the laminar flow, the hot-film foil is embedded in the model. In the steady case the upper surface of the model was observed with two infrared cameras. The model was installed in the institutes 2D test set-up for forced pitch oscillations. Under harmonic pitch oscillations the time dependent pressure distribution, global forces and the variation of the transition region were measured for three different flow conditions (subsonic, weak transonic and transonic with strong shock and possible separation). The results may lead to a physical understanding of the interaction of unsteady transition and shock position and act as validation data for new unsteady transition prediction models.