直角分岐管内振動流の流量分配特性に関する研究(流体工学,流体機械)  [in Japanese] Flow Distribution in a Right Angle Branch During Oscillatory Flow  [in Japanese]

The distribution of flow in a right angle branch during oscillatory flow was studied to clarify the flow phenomena in avian lung. Temporal variation of flow rate was measured by a laser-Doppler velocimeter, and differential pressure between the main and the side branch by a pressure transducer. Flow patterns at the bifurcation were visualized with a tracer method. The results show that the direction-dependent flow separation at the bifurcation affects the flow distribution and causes a net flow from the side branch to the main branch. The net flow magnitudes increase with an increase in the Reynolds number, defined using the cross-sectional average velocity amplitude and the tube diameter in the primary tube. The results also show that the net flow is enhanced by the constriction installed at the entrance of the bifurcation.