헬리콥터 주로터 소음 저감 설계를 위한 와류법과 FW-H 음향상사법 기반의 공력 소음 예측 코드 개발

Abstract

A noise prediction code for helicopter rotors was developed using a nonlinear vortex lattice method (NVLM) and the Ffowcs Williams-Hawkings acoustic analogy with impermeable boundary conditions. Aerodynamic loading was evaluated by coupling NVLM with a vortex particle method to compute loading and thickness noise. The code was validated using Caradonna-Tung and HART-II rotor data under hover and forward flight conditions, respectively. While pitch angle had minimal influence on thickness noise, overall noise levels increased with pitch. The predicted aerodynamic forces and acoustic pressures showed good agreement with measurements, demonstrating the capability of code for designing low-noise rotor blades.