Published 4 issues per year
ISSN Print: 1065-3090
ISSN Online: 1940-4336
Indexed in
VISUALIZATION OF OSCILLATORY FLOW IN A BRANCHED TUBE
ABSTRACT
Oscillatory water flows in a branched tube were visualized by tracer methods to obtain a fundamental view of the flow phenomena effective for the enhancement of gas exchange in the human lung system. From the results, longitudinal vortices were found in the branched region, which were well known as the secondary flow vortices in a curved flow channel. The longitudinal vortices were observed to interact with the flow separation at the branch position, and to cause strong mixing. The effect of the longitudinal vortices on mass transport in the flow was studied from the measurement of the local concentration of the mingled ink in water in a curved tube where a pair of longitudinal secondary vortex was generated. The results revealed that the effective diffusion coefficient in the curved tube was about 3.2 times larger than that in a straight tube for the studied case.