急回転・急発進する円柱まわりの低レイノルズ数流れの漸近解析 : 流体工学,流体機械

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This paper describes the two-dimensional unsteady low-Reynolds-number flow past an impulslvely started rotating and translating circular cylinder. Invoking the vorticity equation, we first derive a system of two coupled integral equations that govern the stream function and a modified vorticity function. This system, singular in the low-Reynolds-number, is then asymptotically solved by using a singular perturbation method and introducing five regions in the space-time domain. The first-order solutions are found to linearly depend on the translating and rotating motions within each region. Because of its importance for applications, a special attention is paid to the lift coefficient C_L which results here from intricate interactions between rotation and translation. The obtained initial asymptotic behavior of C_L actually exhibits a t^<-1/2> singularity and thereby differs from the prediction of Badr & Dennis^<(1)> at moderate Reynolds numbers.
社団法人日本機械学会の論文
2001-07-25