표제지
요약문
Abstract
목차
기호 설명 9
I. 서론 13
1. 연구 배경 및 목적 13
2. 연구 방법 15
II. 본론 16
1. 유인드론용 프로펠러 및 익형 16
1.1. 익형 16
1.2. 이산 소음 18
1.3. 광대역 소음 26
1.4. 음압 레벨 26
2. 유인드론용 프로펠러 실험 및 해석 30
2.1. 프로펠러 형상 30
2.2. 프로펠러 추력 실험 33
2.3. 프로펠러 유동 해석 35
2.4. 해석 데이터 저장 45
3. 소음 수치 해석 46
3.1. 데이터 변환 46
3.2. 수음지 모델링 48
3.3. 데이터 보간 기법 51
3.4. 소음 해석 결과 55
III. 결론 58
참고문헌 60
Table. 1. A-Weighting Table 29
Table. 2. Upstream propeller data (t=0s) 46
Table. 3. Downstream propeller data (t=0s) 47
Table. 4. Upstream propeller force data (t=0s) 48
Table. 5. Downstream propeller force data (t=0s) 48
Table. 6. Coordinate values of observing locations 50
Table. 7. Average Sound pressure level and Sound power level 57
Fig. 1. 3D airfoil geometry (NACA 0015) 17
Fig. 2. 1-D Harmonic wave propagation 20
Fig. 3. Ratio of chord length distribution 31
Fig. 4. Twist angle distribution 31
Fig. 5. Counter-rotating propellers 3D model 32
Fig. 6. Counter-Rotating Propeller thurst force experiment set up 34
Fig. 7. Thrust force coefficient in terms of rotation speed 34
Fig. 8. Computational domain 38
Fig. 9. Stationary domain mesh 39
Fig. 10. Downstream rotationary domain mesh 40
Fig. 11. Upstream rotationary domain mesh 40
Fig. 12. Velocity distribution of propellers (1,000 RPM) 42
Fig. 13. Thrust coefficient in terms of rotation speed 42
Fig. 14. Velocity distribution of propellers (at t=0.12s) 44
Fig. 15. Vorticity distribution of propellers (at t=0.12s) 44
Fig. 16. CFD-Post auto export data code 45
Fig. 17. Geometry of observing location 49
Fig. 18. Plot of linear & cubic interpolation 52
Fig. 19. Plot of pchip & smoothingspline interpolation 52
Fig. 20. Plot of differentiated curves 53
Fig. 21. Plot of second differentiated curves 54
Fig. 22. Acoustic pressure at observing locations 56
Fig. 23. Sound pressure level at observing locations 57