Results Of The 1986 Nasa Faa Dfvlr Main Rotor Test Entry In The German Dutch Wind Tunnel Dnw

Download or read book Results of the 1986 Nasa/Faa/Dfvlr Main Rotor Test Entry in the German-Dutch Wind Tunnel (Dnw) written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-24 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: An acoustics test of a 40%-scale MBB BO-105 helicopter main rotor was conducted in the Deutsch-Niederlandischer Windkanal (DNW). The research, directed by NASA Langley Research Center, concentrated on the generation and radiation of broadband noise and impulsive blade-vortex interaction (BVI) noise over ranges of pertinent rotor operational envelopes. Both the broadband and BVI experimental phases are reviewed, along with highlights of major technical results. For the broadband portion, significant advancement is the demonstration of the accuracy of prediction methods being developed for broadband self noise, due to boundary layer turbulence. Another key result is the discovery of rotor blade-wake interaction (BWI) as an important contributor to mid frequency noise. Also the DNW data are used to determine for full scale helicopters the relative importance of the different discrete and broadband noise sources. For the BVI test portion, a comprehensive data base documents the BVI impulsive noise character and directionality as functions of rotor flight conditions. The directional mapping of BVI noise emitted from the advancing side as well as the retreating side of the rotor constitutes a major advancement in the understanding of this dominant discrete mechanism. Brooks, Thomas F. and Martin, Ruth M. Langley Research Center NASA-TM-100507, NAS 1.15:100507 RTOP 505-63-51-06