旋转弯曲管道内脉冲流动的二次流动

对旋转弯曲管道中的脉冲流动进行了数值模拟，系统地分析了单脉冲和周期性脉冲流动在科氏力和离心力共同作用下的主流速度、二次流动变化情况，研究结果表明：旋转弯曲管道内脉冲流的流动特性主要由Dean数、曲率、周期内的最大科氏力与离心力之比、间歇频率参数和Womersley数来决定；间歇期内，流动并不立即消失，管道内出现反向流动；对于周期性脉冲流动，周期末的残余速度对整个周期的流动结构有着重要影响，间歇频率越大，残余速度的影响就越明显，旋转的作用有削弱残余速度作用的效果，当管道高速旋转时，残余速度的影响几乎可以忽略不计。

Numerical analysis on unsteady intermittent flow in a rotating curved pipe

A numerical study was performed to study the characteristics of unsteady intermittent flow in a rotating curved pipe. Due to the rotation,both the Coriolis force and the centrifugal force could contribute to the unsteady intermittent flow and some complicated phenomena can occur. The results reveal that the unsteady intermittent flow is mainly characterized by the following parameters: the Dean numbers,the curvature,the maximal force ratio in a cycle (the maximal ratio of Coriolis force to centrifugal forces in the cycle),the intermittent frequency parameter (the ratio of non- flux time to the cycle period), and the Womersley number. The effects of rotation and intermittent frequency parameter on the flow transition of secondary flow,and main flow are examined in detail. Certain hitherto unknown flow patterns were found. The present work revealed the nature of the unsteady intermittent flow in a rotating curved pipe.