Instability of the Shear Layer Separating from a Circular Cylinder
Abstract
The instability of the shear layer separating from a circular cylinder has been investigated using large eddy simulation at two different Reynolds numbers of 1600 and 3900 based on the free-stream velocity and cylinder diameter. Two distinct types of the shear layer instability are found in this study: one is a completely three-dimensional type and the other is a quasi-two-dimensional type. The instability of three-dimensional type is generated by a strong counter-rotating streamwise vortex pair underneath the separating shear layer and thus occurs locally in the spanwise direction. On the other hand, the instability of quasi-two-dimensional type is associated with the breakdown of the Karinan vortex shedding process and thus occurs globally across the cross-stream direction as well as the spanwise direction, resulting in the in-phase shear layer instability. It is also conjectured that at high Reynolds number, the instability of quasi-two-dimensional type should be more frequent than the instability of three-dimensional type.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2001
- Accession Number
- ADP013694
Entities
People
- Haecheon Choi
- Jin-Sung Kim
Organizations
- Seoul National University