PIV Measurements in the Wake of a Full-Scale Rotor in Forward Flight

Abstract

Stereo Particle Image Velocimetry (PIV) measurements were acquired in the wake of a full-scale UH-60A rotor that was tested in the National Full-Scale Aerodynamics Complex (NFAC) 40-Ft by 80-Ft Wind Tunnel. Flow field velocities were measured in a stationary cross-flow plane located at approximately 90 deg rotor azimuth. The region of interest was 4-ft high by 13-ft wide and covered the outer half of the blade radius. All measurements were acquired in forward flight conditions. The laser and camera systems were synchronized with the rotor 1/rev so that measurements were acquired for different rotor blade azimuths. The main objective of this paper is to describe the design of the PIV system and the installation of the system components in the wind tunnel. Examples of measured velocity fields are presented. These measurements represent the first PIV measurements to be made in the U. S. on a full-scale rotor in forward flight.