An optical position monitoring system for investigation of model displacement and transient motion of wind tunnel models

A nonintrusive optical model displacement monitoring system is presented, which was primarily developed for wind tunnel model monitoring purposes. To solve the described problem an optical system has been developed which basically focuses the model, or part of it, onto an image plane where a line sensor is placed, utilising four independent line CCD sensors with a data rate of 6.4 kHz. To evaluate the data from the line sensors digital image processing is used to transform the data from the sensor frame of reference to the wind tunnel co-ordinate system leading to the actual model position within the wind tunnel frame of reference. The spatial resolution of the system is better than 0.3 %. The position monitoring system has been successfully applied in the DNW-TWG. The position of a delta wing model has been determined by means of the newly developed optical position monitoring system of DLR. It was possible to determine the displacement due to mean loads and the transient motion of the model for different Mach numbers, different rolling rates and angles of attack up to 25°