円孔を通る周期変動粘性流 : はく離を伴う場合

概要

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The N-S equations formulated with the orthogonal curvilinear coordinate system have been solved numerically for periodic viscous flows through a circular hole driven by fluctuating far field pressure. The flow patterns and acoustic impedance of the circular hole are investigated for various combinations of pressure/viscous force ratio, fluctuating frequency and hole edge thickness. For the high frequency and low pressure range, there is no laminar separation, and the resistance is independent of the periodic pressure amplitude. For the intermediate frequency and pressure range, an attached separation bubble is generated near the downstream side of the hole edge, and the resistance is larger for smaller hole edge thickness and smaller force ratio. For the low frequency and high pressure range, the separation bubble grows to a detached vortex ring and the resistance is proportional to the square root of the pressure amplitude but independent of the viscousity of the fluid and almost invariant with the frequency.
一般社団法人日本機械学会の論文
1990-07-25