3 Component Laser-Doppler-Velocimetry applied in DNW

Kurzfassung

Within the scope of a co-operative programm(1) between DLR and US Air Force and the DLR programme cp-rot a three component laser-Doppler-velocimeter together with a position monitoring system has to be developed in order to determine the unsteady flow field around a rotating helicopter rotor blade. Most of these measurements have to be performed in the DNW (Deutsch- Niederlaendischer Windkanal, The Netherlands), a large wind tunnel with an open test section of 6m - 8m. Experiences from previous testsin the DNW on the same helicopter rotor blade with different LDV set-ups were gained and finally led to a 3 component LDV with a working distance of 5m and a 350mm aperture reveiving optics. By the new set-up it was possible to obtain high qualitiy data although the total laser power does not exceed 3 Watts.