Tiltrotor aeroacoustic code (TRAC) predictions and comparison with measurements

A new rotor noise prediction system called the TiltRotor Aeroacoustic Code (TEUC) has been developed. This system couples the comprehensive rotorcraft code CAMRAD.Mod1 with either the high resolution sectional loads code HIRES or the full potential rotor code FPRBVI to predict unsteady blade loads, which are then input to the noise prediction program WOPWOP. In this paper using the HIRES option, predictions are compared to measured noise for an isolated proprotor (tiltrotor) operating over an extensive range of conditions. The measurements were acquired for a 15 percent scale JVX tiltrotor model in the 14- by 22-Foot Subsonic Tunnel at the NASA Langley Research Center. The effect of rotor angle and CT are examined for different equivalent flight conditions. Predicted tiltrotor wake geometries and wake cortex structure, employing the recently developed multi-core, roll-up wake model, provides insight into the physics of tiltrotor blade-vortex interactions. This provides an explanation to unique tiltrotor BVI noise trends.