난류경계층의 3차원 헤어핀 다발구조에 대한 실험적 연구 = Experimental study on the three-dimensional topology of hairpin packet structures in turbulent boundary layers

다국어 초록 (Multilingual Abstract)

This experiment has been carried out to find the structure of turbulent boundary layer with instantaneous velocity fields obtained in stream-wall-normal planes using a stereo-PIV (Particle Image Velocimetry) method. And it has been measured prependicular plane and horizontal plane with hairpin vortex structure by Reynolds number charge and made third dimension shape for section of horizontal plane through stereo-PIV. In the other layer hairpin vortices occur in streamwise-aligned packets that propagate with small velocity dispersion. A streaky structure is composed of counter-rotating vortex. According as y+ increases, streaky structure's interval space decrease, and its shows that hairpin shape of prior research is vertified. The objective of the present research is to gain a better understanding of coherent structures in the outer of wall turbulence by experimentally examining coherent structures.

목차 (Table of Contents)

• 목차
• 1. 서론 = 1
• 1.1 연구배경 = 1
• 1.2 연구목적 = 3
• 2. 실험장치 및 연구방법 = 5
• 2.1 연구방법 = 5
• 2.2 풍동 설계 및 제작 = 8
• 2.3 3차원 속도장 측정 기법 구축 = 10
• 2.4 입자발생장치 = 16
• 2.5 실험조건 = 19
• 3. 실험결과Ⅰ(평균유동장) = 21
• 4. 실험결과Ⅱ(순간유동장) = 28
• 4.1 Re_θ=934, y^+=43.62에서의 속도장 = 38
• 4.1.1 Re_θ=934, y^+=43.62 에서의 x-y 속도장 = 28
• 4.1.2 Re_θ=934, y^+=43.62 에서의 3차원 속도장 = 29
• 4.2 Re_θ=934, y^+=87.24 에서의 속도장 = 38
• 4.2.1 Re_θ=934, y^+=87.24 에서의 x-y 속도장 = 38
• 4.2.2 Re_θ=934, y^+=87.24 에서의 3차원 속도장 = 38
• 4.3 Re_θ=514, y^+=24.2 에서의 속도장 = 42
• 4.3.1 Re_θ=514, y^+=24.2 에서의 x-y 속도장 = 42
• 4.3.2 Re_θ=514, y^+=24.2 에서의 3차원 속도장 = 42
• 4.4 Re_θ=514, y^+=48.4 에서의 속도장 = 47
• 4.4.1 Re_θ=514, y^+=48.4 에서의 x-y 속도장 = 47
• 4.4.2 Re_θ=514, y^+=48.4 에서의 3차원 속도장 = 47
• 5. POD 해석 = 51
• 5.1 POD(proper Orthogonal Decomposition)정의 = 51
• 5.2 Theory of Proper Orthogonal Decomposition = 51
• 5.3 POD 해석 수행결과 = 52
• 6. 결론 = 57
• 참고문헌 = 59
• Abstract = 61