大きい貯水槽に接続した円管内で振動する流れの管端近傍の挙動 : 流体工学,流体機械

概要

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The characteristics of unsteady flow generated by sinusoidal motion of fluid in a circular pipe connected perpendicularly with the wall of a large vessel have been investigated experimentally. The time-dependent velocity fields near the opening of the pipe are obtained systematically by the visualization method for a wide range of the Womersley number a and the Reynolds number Re, and also measured minutely by a laser Doppler velocimeter for flows at Re=1 000 and a=10〜25. The results show that the flow Patterns are classified Into three types judged from the behavior of fluid particles passing through the pipe opening. For low Womersley numbers of a^<2.1>/Re < 0.25, the flow out of the pipe produces vortex rings in the vessel and fluid different from that discharged into the vessel comes into the pipe along the vessel wall. For sufficiently high Womersley numbers of a^<1.8>/Re > 0.29, on the other hand, the flow consists of a circulation around the pipe edge and axially reciprocating motion through the central part of the pipe opening. An explanation is provided for the formation and the flow behavior of the vortex rings, the features of which are dependent on a and Re.
2001-09-25