A bubble-type vortex breakdown is known as a topological change of streamlines. Topological approaches from the aspect of the dynamical system theory are promising to elucidate the fundamental structure of the vortex breakdown and classify the geometrical features into various classes. In this paper, in order to clarify a relation between a bifurcation process of the topology of streamlines and tensor invariants of the velocity gradient tensor, a bubble-type vortex breakdown was numerically simulated and the invariants of the velocity gradient tensor were examined. Our result showed that the structure of a longitudinal vortex was highlighted by the negative discriminant of the velocity gradient tensor and a minimum velocity inside the bubble-type vortex breakdown was on a surface where its determinant was zero.
内容記述
形態: カラー図版あり
内容記述（英）
Physical characteristics: Original contains color illustrations
バブル型渦崩壊現象の軌道構造とテンソル不変量に関する考察
AA1830029025.pdf
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