아임계 영역에서 강제 진동하는 실린더 주위 유동 특성

Abstract

This study aims at investigating the flow characteristics of the forced vibrating cylinder in the subcritical regime which covers the wide range of 10^3<Re<2×10^5. Interestingly, for the flow around the fixed cylinder, Strouhal number remains nearly constant with a value of 0.2, namely, the flow characteristics are rarely sensitive to the Reynolds number in the subcritical regime. Moreover, the detailed information of the flow physics has been systematically discussed for decades. Contrary to the fixed cylinder, there remains a question about whether the flow characteristics can be affected by the Reynolds numbers for the forced vibrating cylinder. To throw light on this question, two Reynolds numbers of 3900and 140,000 were considered, and the large eddy simulation was employed to simulate the turbulent flow around the forced vibrating cylinders. The reason for the choice of the Reynolds numbers is that the relevant studies of the forced vibration cylinder at the high Reynolds numbers (O~105) are sparse in spite of its importance. Therefore, the present study will be able to provide a meaningful information in terms of the practical view of the vortex-induced vibration (VIV) and to improve our physical understating of VIV. For the studies of the forced vibration cylinder, Bishop and Hassan (1964) firstly discovered the abrupt change in the force acting on the cylinder and the phase jump between the lift and the cy