높은 레이놀즈수에서 와류에 의해 진동하는 원통에 대한 수치해석적 연구
Numerical Study on Vortex Induced Vibration of a Circular Cylinder at High Reynolds Numbers
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초록
유동장 내 물체 주위에 발생하는 와류에 의하여 물체가 진동하는 현상은 다양한 산업 분야에서 흔히 찾아볼 수 있다. 이러한 현상은 구조물의 피로와 같은 안전과 관련한 중요한 문제로 인식되어왔으며 최근 이를 이용한 에너지를 생산하는 분야로 확장되어 연구가 진행되고 있다. 본 연구에서는 2차원 SA 난류 모델 (Spalart- Allmaras model)과 RANS (Reynolds-Averaged Navier-Stokes) 방정식을 이용하여 높은 레이놀즈수 영역에 대하여 유동장 내 와류 발생으로 인한 원통의 진동에 대하여 살펴보았다. 와류발산과 원통 진동의 동기화가 발생하는 lock-in 영역에서 본 수치해석적 연구는 원통의 최대 진폭 예측에서 실험 결과와 다소 차이를 보였다. 와류에 의한 원통의 진동수와 원통 구조물의 고유진동수 비의 변화에서는 초기분기에서 상위분기 및 상위분기에서 하위분기로의 천이 시점의 예측은 실험 결과와 좋은 비교를 보였다.
Abstract
Vortex shedding from a bluff body in the flow field yields an external force acting on the object. This causes an elastic body to vibrate (VIV, vortex induced vibration) and also affects the evolution of vortices. This interaction between vibrating structures and vortices is being studied in various industrial fields in relation to structural fatigue. VIV is influenced by various system variables such as fluid-to-structure mass ratio, structural stiffness, damping, and surface roughness. Experimental studies were conducted on various structural stiffnesses and damping for a cylinder oscillating perpendicular to the flow in a channel. In many cases, investigations have been conducted on laminar flow with low Reynolds numbers or cases lower than the critical Reynolds number. Turbulence characteristics are not dominant and the shear layer has strong two-dimensional characteristics in such regimes. Previous researches for high Reynolds number, however, are limited. Current investigation was conducted on a circular cylinder moving induced by vortices at various high Reynolds numbers through numerical analyses. In predicting the maximum amplitude of the cylinder vibration, the results of this study showed a good comparison with the experiment at low Reynolds number in the initial branch, but showed some differences from the experiment in the condition where synchronization of vortex shedding and cylinder vibration occurs in lock-in regime. In the ratio of the vibrating frequency and the natural frequency of the cylinder, the prediction of the transition from the initial branch to the upper branch and from the upper branch to the lower branch showed good comparison with the experiment.
참고문헌 (18)
- M. M. Bernitsas, "Induced separation and vorticity using roughness in VIV of circular cylinders at 8×103 < Re <1.5×105", 27th International OMAE'08 Conference (2008)
- J. H. Lee, "High-damping, high-Reynolds VIV tests for energy harnessing using the VIVACE converter", Ocean Engineering, 38, pp.1697~1712 (2011)
- J. H. Lee, "Hydrokinetic power harnessing utilizing Vortex Induced Vibrations through a virtual c-K VIVACE model", Ph.D, pp.2010
- C. C. Chang, "Hydrokinetic energy harnessing by enhancement of Flow Induced Motion using Passive Turbulence Control", Ph.D, pp.2010
- C. C. Feng, "The measurement of vortex-induced effects in flow past astationary and oscillating circular and D-section cylinders", Master, pp.1968
- A. Khalak, "Motions forces and mode transitions in vortex induced vibrations at low mass-damping", Journal of Fluids and Structures, 13, pp.813~851 (1999)
- F. Hover, "Vortex-induced vibration of marine cables : experiments using force feedback", Journal of fluids and structures, 11(3), pp.307~326 (1997)
- V. T, Nguyen, "Detached eddy simulations of flow induced vibrations of circular cylinders a thigh Reynolds numbers", Journal of Fluids and Structures, 63, pp.103~119 (2016)
- N. B. Khan, "Numerical investigation of the vortex-induced vibration of an elastically mounted circular cylinder at high Reynolds number(Re = 104)and low mass ratio using the RANS code", PLoS ONE, 12, pp.e0185832~ (2017)
- T. A. Sarpkaya, "critical review of the intrinsic nature of vortex-induced vibrations", Journal of Fluids and Structures, 19, pp.389~447 (2004)
- M. Breuer, "Large eddy simulation of the subcritical flow past a circular cylinder Numerical and modeling aspects", International Journal Numerical Methods Fluids, 28, pp.1281~1302 (1998)
- P. Bearman, "Circular cylinder wakes and vortex-induced vibrations", Journal of Fluids and Structures, 27, pp.648~658 (2011)
- M. M. Zdravkovich, "Flow around circular cylinders Volume 1: Fundamentals" (1997), Oxford University Press
- "Fluent Tutorial Guide 2020 R2, User’s Manual", ANSYS, ~ (2020)
- W. Wu, "Two-dimensional RANS simulation of flow induced motion of circular cylinder with passive turbulent contrl", Ph.D, pp.2011
- A one-equation turbulence model for aerodynamic flows, "P. Spalart", American Institute of Aeronautics and Astronautics, ~, pp.Technical Report AIAA-92-0439 (1992)
- W. J. Kim, "Effects of swirl number on flow characteristics of radial swirler for gas turbine engine", Journal of Knowledge Information Technology and Systems(JKITS), 15(5), pp.785~793 (2020)
- K. M. Hyun, "Breathing characteristics analysis of snoring state using air flow in the nose", Journal of Knowledge Information Technology and Systems(JKITS), 14(6), pp.585~594 (2019)