2002 年 22 巻 1Supplement 号 p. 107-110
Two type methods for identifying vortex structure have been applied to a complex internal flow field in engineering application. One defines the vortex core by the pressure minimum in the flow field. The other identifies the vortex axis by a semi-analytic method based on the critical-point theory. The latter is found to capture the vortex core sharply in spite of the large pressure gradient in the main stream. The distribution of normalized helicity along the vortex core identified is very useful in investigating the nature of the vortex quantitatively.