Journal of Flow Visualization and Image Processing

ISSN for PRINT: 1065-3090

For Online Access

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2006, Volume13

Issue 2

110 pages

DOI: 10.1615/JFlowVisImageProc.v13.i2

Issue price - $154.00

Eiji Sakai
Department of Aeronautics and Astronautics, University of Tokyo

Toshinori Watanabe
Department of Aeronautics and Astronautics, University of Tokyo, Tokyo 113-8656, Japan

Takehiro Himeno
Department of Aeronautics and Astronautics, University of Tokyo

It is widely known that a unidirectional flow is generated in the avian lung during a breathing process. Though the unidirectional flow should be caused by a kind of an aerodynamic valve, its generation mechanism is not fully understood. In the present study, therefore, the oscillatory flow field in a right-angle branched tube, that was a bifurcation model of the avian trachea, was visualized and analyzed both experimentally and numerically to reveal the mechanisms of the unidirectional flow. The experimental results showed that a separation vortex observed at the entrance of a side-daughter tube played an important role for generation of the unidirectional net flow. The convective inertia was also suggested to be important in the process. From the numerical simulation, the details of the flow mechanism were revealed. The inertia force was found to drive the unidirectional flow during the whole period of oscillation. A good correlation was found between the pressure drop in the branched tube due to the separation vortex and the induced velocity of the unidirectional flow.

DOI: 10.1615/JFlowVisImageProc.v13.i2.20 Download article, 113-132 pages

Article price - $35.00

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