Aeroacoustic Codes for Rotor Harmonic and BVI Noise—CAMRAD.Mod1/HIRES

Abstract

This paper presents a status of non-CFD C aeroacoustic codes at NASA Langley Research Center for the prediction of helicopter harmonic and Blade-Vortex Interaction (BVI) noise.The prediction approach c incorporates three primary components: CAMRAD.Modl -a substantially modified version of R the performance/trim/wake code CAMRAD; HIRES -a r high resolution blade loads post-processor; and r WOPWOP -an acoustic code.The functional rc capabilities and physical modeling in rv CAMRAD.Modl/HIRES will be summarized and r',r" illustrated.A new multi-core roll-up wake modeling approach is introduced and validated.Predictions of X rotor wake and radiated noise are compared with to the results of the HART program, a model BO-105 Y windtunnel test at the DNW in Europe.Additional comparisons are made to results from a DNW test of a Y contemporary design four-bladed rotor, as well as from a Langley test of a single proprotor (tiltrotor) three-bladed model configuration.Because the method is shown to help eliminate the necessity of guesswork in setting Z code parameters between different rotor configurations, it should prove useful as a rotor noise design tool.