A SEPARATED-FLOW MODEL FOR COLLAPSIBLE-TUBE OSCILLATIONS
A SEPARATED-FLOW MODEL FOR COLLAPSIBLE-TUBE OSCILLATIONS
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DOI：
10.1017/s0022112085002427
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发表时间：
1985-01-01
影响因子：
3.7
通讯作者：
PEDLEY, TJ
中科院分区：
文献类型：
--
作者：
CANCELLI, C;PEDLEY, TJ
提出了一种新的可折叠管流动模型，用于描述安装在两根刚性管之间并被加压容器包围的可折叠管段内的流动。该模型的新特征包括(a)纵向壁张力和(b)坍塌管中随时间收缩的分离流下游的能量损失，其方式与一维运动方程一致。在精确模拟稳态坍缩的同时，该模型还预测了自激振荡，其振幅足够大，只有当可坍缩管中的流动在某处达到超临界（流体速度超过长波传播速度）时才能观察到。振荡的动力学是由流动分离点的纵向运动决定的，这是对逆压力梯度的响应，逆压力梯度与在收缩的（移动的）最窄点和管道出口之间向后和向前传播的波有关。
A new model is presented to describe flow in segments of collapsible tube mounted between two rigid tubes and surrounded by a pressurized container. The new features of the model are the inclusion of (a) longitudinal wall tension and (b) energy loss in the separated flow downstream of the time-dependent constriction in a collapsing tube, in a manner which is consistent with the one-dimensional equations of motion. As well as accurately simulating steady-state collapse, the model predicts self-excited oscillations whose amplitude is large enough to be observable only if the flow in the collapsible tube becomes supercritical somewhere (fluid speed exceeding long-wave propagation speed). The dynamics of the oscillations is dominated by longitudinal movement of the point of flow separation, in response to the adverse pressure gradient associated with waves propagating backwards and forwards between the (moving) narrowest point of the constriction and the tube outlet.