| Popis: |
Vortex breakdowns are organized structures that usually lead to turbulent flow in vortices. They are among the many kinds of large amplitude disturbances that are possible in concentrated vortices having a streaming component of velocity along the vortex axis. While there is no universal agreement on a definition of “vortex breakdown”, most observers associate the term with a condition in which there is a rapid axial deceleration of the fluid leading to a stagnation point and region of reversed axial flow. By rapid, I mean that the fluid on the vortex axis is brought to rest in distances comparable to the vortex core diameter. Since this distance is small compared to the length scales of interactions generally taking place in concentrated vortices, the occurrence of vortex breakdown appears as a dramatic event. |
