The whirl and generated forces of rotating cylinders with different diameters placed in still water and in flow are studied experimentally. For the rotating cylinders in still water, the Same Frequency Whirl (SFW) and Different Frequency Whirl (DFW) have been identified and illustrated. The corresponding SFW and DFW areas are divided. The Root Mean Square (RMS) values of the generated force coefficient dramatically increase in the defined ranges of Resonance I and Resonance II. For the rotating cylinders in flow, the hydrodynamics, SFW and DFW are illustrated. The hydrodynamic, SFW and DFW areas are divided. The RMS values of the generated forces in the range of Resonance II are much smaller than those in still water due to the generated lift forces. The discussion suggests that the frequency of the DFW may equal multiple times or one-multiple times that of the rotating frequency: the whirl direction of the DFW with multiple times the frequency of the rotating frequency is the same as the rotating direction. The whirl direction of the DFW with one-multiple times frequency of the rotating frequency is opposite to the rotating direction.

实验研究了放置在静止水中和流动中的不同直径旋转圆柱体的涡流和产生力。对于静止水中的旋转气缸，已经确定并说明了相同频率旋转（SFW）和不同频率旋转（DFW）。划分了相应的SFW和DFW区域。产生的力系数的均方根（RMS）值在共振I和共振II的定义范围内急剧增加。对于流动中的旋转气缸，显示了流体动力学，SFW和DFW。流体动力，SFW和DFW区域被划分。由于产生的升力，在共振II范围内产生的力的RMS值比静止水中的RMS值小得多。讨论表明，DFW的频率可以等于旋转频率的倍数或一倍：DFW的旋转方向是旋转频率的倍数，与旋转方向相同。旋转频率的一倍频的DFW的旋转方向与旋转方向相反。