공력 소음 통합 해석 프레임워크를 이용한 AAM 프로펠러 최적화 = Optimization of AAM Propellers Using an Integrated Aerodynamic and Aeroacoustic Analysis Framework

다국어 초록 (Multilingual Abstract)

Propeller noise has become a critical design constraint for advanced air mobility (AAM), particularly in urban and low-altitude operations where acoustic comfort and environmental regulations are increasingly important. While conventional propeller design approaches primarily focus on aerodynamic performance, neglecting noise considerations can lead to designs that are aerodynamically efficient but acoustically unacceptable. Therefore, a systematic design framework that simultaneously considers aerodynamic performance and aeroacoustic characteristics is required.
In this study, an integrated aerodynamic and aeroacoustic analysis and optimization framework for AAM propellers is developed. Aerodynamic performance is predicted using a Blade Element Momentum Theory (BEMT) based analysis, which provides sectional aerodynamic quantities such as lift, drag, angle of attack, and blade loading. Discrete noise is predicted using the Farassat Formulation 1A based on unsteady blade loading and thickness effects, while broadband noise is estimated using the semi-empirical Brooks, Pope, and Marcolini (BPM) model. By coupling these aerodynamic and aeroacoustic models, both tonal and broadband noise components of AAM propellers are quantitatively evaluated under various operating conditions.
Based on the integrated analysis framework, an OpenMDAO optimization environment is constructed to perform aerodynamic and aeroacoustic shape optimization of propeller blades. Blade geometry parameters, including pitch angle distribution and chord distribution, are used as design variables, while thrust requirements are imposed as constraints. The optimization objective is defined to minimize overall sound pressure level (OASPL), considering both discrete and broadband noise contributions, while maintaining aerodynamic performance.
The proposed framework is applied to AAM propeller configurations to investigate the effects of blade geometry and pitch angle variations on aerodynamic performance and noise characteristics. The results demonstrate that the integrated optimization framework can effectively identify propeller designs that achieve reduced noise levels without sacrificing thrust performance. This study provides a practical and extensible methodology for the aerodynamic and aeroacoustic optimization of AAM propellers and offers a foundation for future multidisciplinary design optimization involving noise-aware rotorcraft design.

목차 (Table of Contents)

• 제1장 서론 1
• 1.1 연구 배경 1
• 1.2 선행 연구 현황 3
• 1.3 연구 목표 5
• 제2장 공력 해석 6
• 2.1 공력 해석 기법 8
• 2.2 에어포일 공력자료 12
• 제3장 소음 예측 16
• 3.1 AAM 소음원 개요 17
• 3.1.1 이산 소음 18
• 3.1.2 광역 소음 19
• 3.2 소음 예측 모델 20
• 3.2.1 Ffowcs Williams-Hawkings 방정식 22
• 3.2.2 Farassat Formula 1A
• 3.2.3 에어포일 자체소음
• 3.3 소음 예측 기법 검증 33
• 3.3.1 1/7 축소형 로터(UH-1H) 35
• 3.3.2 UH-1H 헬리콥터 로터
• 제4장 저소음 블레이드 형상 설계 39
• 4.1 통합 해석 프레임워크 구조 39
• 4.2 블레이드 형상 설계 43
• 4.2.1 코드 길이 분포 설계 43
• 4.2.2 비틀림각 분포 설계 45
• 4.2.3 에어포일 분포 47
• 4.2.4 블레이드 형상 비교 51
• 4.3 운용 조건 53
• 4.4 공력 해석 결과 55
• 4.5 소음 예측 결과 60
• 4.5.1 이산 소음 예측 결과 60
• 4.5.2 광역 소음 예측 결과 68
• 제5장 블레이드 형상 최적화 75
• 5.1 최적화 기법 75
• 5.2 최적화 문제 정의 및 설계 변수 설정 79
• 5.3 최적화 수행 및 수렴 과정 81
• 5.4 공력 성능 및 소음 저감 효과 분석 87
• 제6장 결론 94
• 참고문헌 96