Model Deformation Measurement in the ONERA F1 Wind tunnel

For wind tunnel tests, particularly when the model is high loaded, its deformation is a very sensitive parameter which can be of the same order of magnitude compared to the Reynolds number. The progresses in the camera resolution as well as in the image treatment methods, give now the possibility to develop and use a reliable MDM (model deformation method) which can be proposed to customers. In 2006 ONERA has decided to develop by its own a MDM system with two main goals: a low measurement uncertainty (lower then 0.1deg for twist) that could be improved continuously, an easy and flexible system with a reduced cost. Our method is based on stereovision principle and model markers. In order to validate the new system, two wind tunnel tests have been performed with a complete civil aircraft model in Fl. This wind tunnel is a low-speed, pressurized wind tunnel of h=3.5 m by w=4.5 m test section used by industry as well as for research activities. This paper is divided into two parts. The first one will present F1 and the different steps of the ONERA MDM method and the associated hardware, the second part will present the main results of two test campaigns performed in a partnership with Airbus, particularly examples of checking of the MDM system and example of model deformation measurements.