PREDICTION AND MEASUREMENT OF BLADE-VORTEX INTERACTION

An extensive quantity of airload measurements was obtained for a press ure-instrumented model of the BO-105 main rotor for a large number of higher harmonic control settings at Duits-Nederlandse Wind Tunnel. The wake geometry, vortex strength, and vortex core size mere also measur ed through a laser light sheet technique and laser Doppler velocimetry , These results are used to verify the blade-vol tex interaction (BVI) airload prediction methodologies developed by Army Aeroflightdynamics Directorate, Deutsche Forschungsanstalt fur Luft-und Raumfahrt, NASA Langley Research Center, and the Office National d'Etudes et de Recher ches Aerospatiales. The comparisons show that an accurate prediction o f the blade motion and the wake geometry is the most important aspect of the BVI airload predictions.