2자유도의 비접촉식 방법을 이용한 다중 실린더의 유동에 의한 진동 특성 연구 = The study of characteristics of flow-induced vibration of multiple cylinder using non-touch method on 2 degree of freedom

다국어 초록 (Multilingual Abstract)

Flow or vortex induced vibration (FIV or VIV) on a structure is caused by drag force and lift force which comes from Karman vortex. Most of previous studies concerning FIV have focused on flow-cross vibration by using directly contacted or restricted measuring methods. In this study, non-touch, two degrees of freedom measurement was conducted by using high speed camera, wind tunnel. From this method, characteristics of FIV could be analyzed without any restrictions.
For two different diameter circular cylinders, the characteristics of different arrangement were studied with comparing the characteristics of two same-diameter cylinders. First, when large cylinder is in upstream, the flow-cross direction amplitude of upstream cylinder is similar with the upstream cylinder amplitude of same-diameter cylinders. But, the peak-amplitude of the downstream cylinder occurs in different region with these of same diameter cylinders. Next, when small cylinder is prior to large cylinder, the maximum amplitude of upstream cylinder occurs in different region with same diameter cylinders. For large downstream cylinder, the amplitude gradually increases without any peak value as the flow velocity increases.
For three same diameter cylinders experiment, the amplitudes of first and second cylinders are similar with those of the two same diameter cylinders. But, the amplitude of last cylinder of three same diameter cylinders gradually increased as without any peak value, and this is different result of last cylinder of two same diameter cylinders. From this results, the presence of third cylinder have no affection to the vibration of upstream cylinders, and the resonance of third cylinder is suppressed by the upstream cylinders.

목차 (Table of Contents)

• 기호설명
• 1. 서론 01
• 1.1 연구 배경 01
• 1.2 배열된 실린더의 진동에 관한 선행연구 02
• 2. 실험 장비 04
• 2.1 실험 장치 및 방법 04
• 2.1.1 지름이 다른 두 실린더의 실험 06
• 2.1.2 지름이 같은 세 실린더의 실험 08
• 2.2 고유진동수 측정 09
• 3. 실험 결과 10
• 3.1 지름이 다른 두 실린더 배열의 진동 분석 10
• 3.1.1 Large-Small (LS) 배열의 2자유도 진동 분석 13
• 3.1.2 Small-Large (SL) 배열의 2자유도 진동 분석 15
• 3.1.3 Large-Small (LS) 배열의 진폭 분석 16
• 3.1.4 Small-Large (SL) 배열의 진폭 분석 18
• 3.1.5 두 배열의 진폭 특성 비교 분석 19
• 3.1.6 두 배열의 진동수 특성 분석 24
• 3.2 지름이 같은 배열된 세 실린더의 진동 분석 27
• 4. 결론 37
• 5. 참고문헌 38
• 6. 부록 41