Measurement of wing deformation in ETW by means of Moiré Interferometry

A non-intrusive Moiré Interferometry system has been designed and installed by DLR to determine the instantaneous deformation of aircraft models during testing in the European Transonic Windtunnel ETW. The lecture describes the principles of the Moiré technique and the experimental set-up of the system. As high accuracy for the measurement of wing twist (< 0.1°) and wing bending (< 0.05 mm) is required, hardware and evaluation software have to be carefully designed. The influence of disturbing effects is discussed in detail, also the solutions to overcome these problems. Measurements of the wing twist of an A 380 type aircraft within the European HiReTT project are described, and results of selected test cases are presented and compared to other experimental and numerical methods

Model Deformation Measurement in ETW using the Moiré Technique

A non-intrusive Moiré Interferometry system has been designed and installed to determine the instantaneous deformation of aircraft models during testing in the European Transonic Windtunnel. The present paper describes the principles of the Moiré technique and the experimental set-up of the system. As high accuracy for the measurement of wing twist (< 0.1°) and wing bending (< 0.05 mm) is required, hardware and evaluation software have to be carefully designed. The influence of disturbing effects is discussed in detail, also the solutions to overcome these problems. Measurements of the wing twist of an A 380 type aircraft within the European HiReTT project are described, and results of selected test cases are presented and compared to other experimental and numerical methods

Application of Moire Interferometry for model deformation measurements in large scale wind tunnels

A non-intrusive Moire interferometry system has been designed to acquire the instantaneous deformation of models during wind tunnel testing. The resulting interferograms are evaluated without manual intervention using a technique based on the Fourier Transform. The system has been installed in the cryogenic European Transonic Wind Tunnel (ETW). The deformation of a model wing (generic model of a transport aircraft with a full span of 1.60m) has been measured. In a second experiment, the bending angle of a flap of a hypersonic vehicle was measured in order to determine the hinge moment due to aerodynamic loads. The experiment was carried out in the Transonic Wind Tunnel Göttingen (TWG

The Use of Non-Standard Video Techniques for Qualitative and Quantitative Flow Visualization

A video stroboscope comprising a user-friendly sequencer to generate the trigger pulses, a frequency-independent digital phase shifter and an asynchronously shuttered progressive scan CCD camera has been developed. The basic features of this system will be explained. Examples of the application of the video stroboscope for visualization of a water jet, the inspection of the human larynx and the deformation of the model of an airplane wing will be give

Effects of pulsed and continuous jet vortex generators in a turbulent boundary layer flow – an investigation using two high-speed stereo PIV systems

Two high-speed stereo PIV systems have been used for the characterization of pulsed and continuous jet actuators in the turbulent boundary layer wind tunnel at ONERA Lille. The test aimed at generating an aerodynamic database useful for the characterization of (unsteady) vortical structures responsible for the wall-normal fluid exchange which enable an increase of wall-shear stress in the wake of the jet actuator row. Averaging over all velocity measurements of the data-set without regarding the different cycle-phases of the jet pulses and calculating the respective scalars and RMS values is the first step in the analysis of the time series of velocity fields. The second step is averaging the different phase-locked positions per cycle so that a quasi-time-resolved reconstruction of the phase average induced vortical wake flow could be realized. Then, a comparison between continuous and pulsed jets through several criteria and an estimation of the minimal number of independent samples in a typical turbulent boundary layer were performed. This work has been realized in close collaboration between ONERA DAAP in Lille, France and DLR-AS-EXV in Göttingen, Germany