Acoustic predictions using measured pressures from a model rotor in the DNWA contemporary design, 4-bladed United Technologies model rotor with pressure-instrumented blades was tested in the Duits-Nederslandse Windtunnel. Simultaneous acoustic and pressure measurements were made for a wide range of operating conditions. Microphones were optimally positioned at a number of locations in the flow forward of the rotor to measure rotor thickness noise, high-speed impulsive noise (both in the rotor plane), and blade-vortex interaction noise (forward and 25 deg below the rotor plane). The blade surface pressure data are used as aerodynamic input to WOPWOP, which is a state-of-the-art rotor noise prediction program that predicts rotor thickness and loading noise. The predicted results using WOPWOP are compared to the measured noise levels for cases where either thickness noise, blade-vortex interaction noise, or high-speed impulsive noise is the dominant noise mechanism. The comparisons show regions of good agreement, as well as areas where further improvement is necessary.
Document ID
19920031761
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Visintainer, Joseph A. (Sikorsky Aircraft Stratford, CT, United States)
Burley, Casey L. (Sikorsky Aircraft Stratford, CT, United States)
Marcolini, Michael A. (NASA Langley Research Center Hampton, VA, United States)
Liu, Sandy R. (U.S. Army, Aeroflightdynamics Directorate, Moffett Field CA, United States)