| Summary: | 碩士 === 逢甲大學 === 水利工程所 === 94 === This study set up a numerical simulation that used to discuss the effect of the flow field of a transversely oscillating cylinder. There are three non-dimensional parameters, i.e. the Reynolds number, the oscillating frequency of the cylinder, and the oscillating amplitude of the cylinder. There have been few cases in numerical simulation, and for the buffer region (between lock-on and unlock-on). So this study use a large number of cases to describe the influence of a oscillating cylinder, especially the influence of the time series of the drag and the lift, and the influence of the buffering region, in addition to the influences of Reynolds number and the oscillating amplitude of the cylinder. The characteristic of flow field includes vortex shedding frequency, effect of lock-on, time-average of the drag coefficient, root mean square of the lift coefficient, and so on. Energy spectrum analysis was used to study the time series of the drag and the lift. Then, the frequency and energy of vortex shedding could be found. The lowest lift and drag, which can be found in the buffer region, were decreasing with increasing Reynolds number. In lock-on region, the lift and drag increased with increasing amplitude of cylinder vibration.
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