A model deformation method applied to PSP measurements

Abstract

A new method has been developed to correct the effects of model deformation on PSP images. This method is based upon grid tracking instead of marker tracking. The grid is stretched according to a deformation law and deformation parameters. The deformation law is designed by using mechanical and aerodynamic knowledge about the model behavior. The parameters are identified by using the same markers that are used for usual PSP applications. The identification algorithm is an extended version of the algorithm that identifies the relative position of the camera and the model. The method has been applied successfully on images obtained in a pressurized wind tunnel at Onera Modane. The achieved accuracy is 0.1 pixel, which is considered as a very good value. The method enables to identify not only deformation parameters but also motion parameters. As a result, the method can be used to measure model deformation and motion, which would be very useful for tests in research and industrial wind tunnels. The method can be extended to handle simultaneously several cameras, thus improving the accuracy.